PACIFIC COOPERATIVE STUDIES UNIT UNIVERSITY OF HAWAII AT MANOA. Department of Botany Maile Way Honolulu, HI Technical Report 129

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1 PACIFIC COOPERATIVE STUDIES UNIT UNIVERSITY OF HAWAII AT MANOA Department of Botany Maile Way Honolulu, HI Technical Report 129 PROCEEDINGS OF WORKSHOP ON BIOLOGICAL CONTROL OF NATIVE ECOSYSTEMS IN HAWAI'I JUNE 2000 Edited by: Clifford W. Smith, Julie Denslow, and Stephen Hight September 2002

2 TABLE OF CONTENTS PREFACE ENHANCING SUCCESSFUL BIOLOGICAL CONTROL OF WEEDS BY EXPANDING AND IMPROVING OVERSEAS RESEARCH. Joe Balciunas. BIOLOGICAL CONTROL OF IVY GOURD, COCClNlA GRANDIS (CUCURBITACEAE), IN HAWAI'I. Marianne E. Chun.. CLASSICAL BIOLOGICAL CONTROL OF CLlDEMlA HlRTA (MELASTOMATACEAE) IN HAWAI'I USING MULTIPLE STRATEGIES. Patrick Conant... HOST SPECIFICITY TESTING OF BIOCONTROL AGENTS OF WEEDS. Tim A. Heard.. HOST SPECIFICITY AND RlSK ASSESSMENT OF HETEROPERREYIA HUBRICHI, A POTENTIAL CLASSICAL BIOLOGICAL CONTROL AGENT OF CHRISTMASBERRY (SCHINUS TEREBINTHIFOLIUS) IN HAWAI'I. Stephen D. Hight.. BIOLOGICAL CONTROL POTENTIAL OF MlCONlA CALVESCENS USING THREE FUNGAL PATHOGENS. Eloise M. Killgore. BlOLOGlCAL CONTROL OF GORSE IN HAWAI'I: A PROGRAM REVIEW. George P. Markin, Patrick Conant, Eloise Killgore, and Ernest Yoshioka.. SETTING PRIORITIES FOR THE BlOLOGlCAL CONTROL OF WEEDS: WHAT TO DO AND HOW TO DO IT. Judith H. Myers and Jessica Ware.. HOST SPECIFICITY TESTING FOR ENCARSIA SPP., PARASlTOlDS OF THE SILVERLEAF WHITEFLY, BEMlSlA ARGENTlFOLll BELLOWS & PERRING, IN HAWAI'I. Walter T. Nagamine and Mohsen M. Ramadan. PREDICTABLE RISK TO NATIVE PLANTS IN BlOLOGlCAL CONTROL OF WEEDS IN HAWAI'I. Robert W. Pemberton. REVIEW AND PERMIT PROCESS FOR BIOLOGICAL CONTROL RELEASES IN HAWAI'I. Neil J. Reimer.. FOREST PEST BIOLOGICAL CONTROL PROGRAM IN HAWAI'I. Clifford W. Smith.. A RESOURCE MANAGER'S PERSPECTIVE ON THE ROLE OF BIOCONTROL IN CONSERVATION AREAS IN HAWAI'I. J.T. Tunison.. STRAWBERRY GUAVA (Psidium catfleianum): PROSPECTS FOR BIOLOGICAL CONTROL. Charles Wikler and Clifford W. Smith.. SYNTHESIS AND CONCLUSIONS; HAWAII BIOCONTROL WORKSHOP.

3 BIOLOGICAL CONTROL OF INVASIVE PLANTS IN NATIVE HAWAIIAN ECOSYSTEMS PREFACE The importation of alien insects and pathogens to control invasive alien weeds raises justifiable concern among land managers and conservationists. Do we risk compounding the problem by introducing yet another alien species for which we have only an imperfect assessment of its risk of becoming invasive itself? What is the likelihood that an imported control agent will affect non-target species or expand beyond expected habitats and host species? For the Hawaiian archipelago the dangers are particularly acute. Hawai'i has many endemic species, a substantial percentage of which are at risk of extinction. The Hawaiian vascular plant flora includes about 1302 taxa (including subspecies and varieties) of which 1158 are endemic (Wagner et a/. 1990). Some 37% of these taxa are endangered or at risk of becoming extinct, representing 38% of all federally listed endangered species in the United States (Loope 1998). Islands, moreover, appear to be particularly vulnerable to invasive species. Over 900 nonindigenous plant species have become naturalized in Hawai'i, more than 90 of which constitute substantial problems for conservation because they compete with native species or so alter ecosystem processes that whole communities are changed (Vitousek and Walker 1989). In spite of the magnitude of the invasive weed problem in Hawai'i, we are unable to predict with any confidence which new plant introductions are likely to become problems in future years. Beyond those species whose invasive tendencies have been demonstrated elsewhere, our understanding of what combination of species traits and ecosystem characteristics produce explosive, habitat-altering population growth is rudimentary. There are good reasons for caution in the use of alien insects and pathogens as control agents for invasive weeds. Nevertheless biological control offers one of the most cost-effective and enduring mechanisms for the control of persistent weeds that have become widely invasive in natural habitats. Chemical and mechanical approaches to the control of weed populations require perpetual maintenance, may inflict unwanted side effects on nontarget species and communities and are of limited use in large diverse ecosystems. Extensive infestations in poorly accessible terrain require considerable long-term investment in personnel and resources, expenditures that may be difficult to justify when short-term economic returns are not apparent. Biological control offers the possibility for ~mi~ra~elyeradication]~sme-eds4v~mive~ieterrain in perpetuity. Yet the technique is far from a panacea. Many years of exploration and host-range testing are necessary before a potential control agent can be brought to the point of release. Limitations of quarantine space and personnel mean that only a handful of agents can be under investigation at any one time. While the numbers of releases resulting in unpredicted impacts on non-target hosts have been low in recent times (J. Balciunas this volume, R. Pemberton this volume), many releases have been less than successful because the agent either fails to establish viable populations andlor is ineffective in limiting populations of the target plant over part or all of its range. Financial constraints frequently inhibit our ability to conduct the necessary studies on the biology of a species in its native environment. Clearly the challenge to the community of scientists and managers seeking to use biological control agents in Hawaii is to make the most efficient use of limited space, personnel, and financial resources in bringing the safest yet most effective insect and

4 pathogen agents on line. The most productive research strategies for meeting that goal was the topic of the 2000 Conservation Forum of the Hawai'i Secretartiat for Conservation Biology: Biological Control of lnvasive Plants in Native Hawaiian Ecosystems. Presenters and discussants were invited to provide both breadth of international experience in a diversity of plant-herbivore-predator systems and depth of understanding of the particular idiosyncracies of island ecosystems. They were charged to take from the theory and patterns of evolutionary and population biology and from the experience gained in Hawai'i to recommend a framework of research priorities and strategies. Such strategies should not only improve the efficiency with which we bring new control agents to the point of release, but also Increase the likelihood that released agents are both effective at reducing population sizes of target species and unlikely to threaten non-target plants. This volume is a compendium of historical syntheses, examples of effective research strategies, and detailed case studies from the Hawaiian experience in biological control. It is capped by a synthesis that arose from discussions of strategies for exploration and country-of-origin studies, of lessons from Hawaiian releases, of protocols for host-range testing, and of appropriate pre-and post-release assessments of impact. It was our hope that the forum would be not only a stimulus for discussion and information exchange, but also a source of renewed energy, direction, and cooperation among the diverse community of scientists and managers concerned for the future of native Hawaiian ecosystems. We are thus grateful for the participation of representatives from many state and federal agencies, of land managers, and of community groups and for the contributions of scientists from the US mainland and abroad who contributed enthusiastically in all aspects of the proceedings. All these components were brought together in a smoothly-run meeting through the efforts of the late Nancy Glover, Director of the Secretariat for Conservation Biology, and her assistant, Moani Pai, who oversaw the conference logistics, and through the excellent management of Audrey Haraguchi and her assistant Olivia Rivera of the Institute of Pacific Islands Forestry, who arranged travel for international and mainland participants. The productivity and quality of the meeting would have been much diminished without their dedicated efforts. We are grateful for financial support from US Department of Agriculture Forest Service International Programs and the lnstitute for Pacific Islands Forestry, from the Secretariat for Conservation Biology, and from the US Geological Service-Biological Resources Division Pacific Cooperative Studies Unit, University of Hawai'i. LITERATURE CITED Loope, L.L Hawall and Pacific Islands. pp , In: M.J. Mac, P.A. Opler, C.E. Puckett Haecker, and P.D. Doran (eds), Status and trends of the nation's biological resources, Volume 2. U.S. Department of the Interior, U.S. Geological Survey, Reston, VA. Vitousek, P.M., and L.R. Walker Biological invasion by Myrica faya in Hawai'i: plant demography, nitrogen fixation, ecosystem effects. Ecological Monogmphs 59: Wagner, W. L., D. R. Herbst, and S. H. Sohmer Manual of the Flowering Plants of Hawai'i. Honolulu, University of Hawaii and Bishop Museum Presses.

5 STRATEGIES FOR EXPANDING AND IMPROVING OVERSEAS RESEARCH FOR BIOLOGICAL CONTROL OF WEEDS Joe Balciunas USDA Agricultural Research Service, Exotic & lnvasive Weed Research Unit, Western Regional Research Center, 800 Buchanan St., Albany, CA Abstract The follomng recommendabons are made to Improve overseas research on blologlcal control agents Conduct more long-term overseas evaluations Place much greater emphasls on field host range studles Carry out more research on Impact and efficacy of potential agents Perform more ecological research overseas on target weed Adhere to lnternatlonal standards for biolog~cal~ontrol studies Document all fin6ngs including failures Key words: pre-release impact assessment, code of best practices, field host range NEED FOR MORE OVERSEAS RESEARCH For many, but not all, invasive exotic pests, classical biological control is a management option that should be considered. For pests that are widespread or established in remote areas, classical biological control may be the only viable control technology. The introduction, release, and establishment of the natural enemies of exotic weeds obviously require research in the region where the pest is native. I began conducting evaluations of potentlal weed b~ocontrol agents in their native range shortly after receiving my Ph.D. in entomology at the end of 1977 (Balciunas and Center 1981). Most of my career has been spent in international exploration, and I've been fortunate to meet and work with many other entomological explorers from many countries, whose task has been to identify potential biocontrol agents in the native range of the host plant. I've also worked closely with quarantine scientists in USA and Australia. Through this experience, I have gained a personal appreciation not only for what types of overseas research works and what doesn't, but also for which approaches are most likely to be effective. The dramatic increase in international travel and commerce regrettably has been accompanied by an increase in the introduction of new weeds. Development of biological control agents for some of these new weeds has been a high priority, but the increase in numbers of targets has required the expansion of investment in international research. In some cases, this has been as simple as choosing a location and cooperator and making arrangements for shipment of potential agents. In other cases, extensive and intenswe research on the potential agent in its native range is not only desirable, but necessary. Practitioners of the biological control of weeds, unlike those involved in the biological control of insect pests, have long sought to minimize impacts on non-target species. Evaluations of host-specificity have been routine for almost four decades. Initially, the concern was primarily non-target impacts on commercial crops, but today, potential nontarget impacts on native plant species receive the most attention. Host specificity with respect to native plant species usually must be evaluated in quarantine where the release is proposed. This has exacerbated a bottleneck to the expeditious evaluation of potential biological control agents because quarantine space and resources are limited and expensive. Moreover, adequate testing to secure approval for release of a new agent usually will require many years of evaluation in quarantine. In contrast, a single weeklong visit to the native host range could easily reveal a dozen species feeding on the target plant. It is more efficient to screen these potential agents for host specificity in

6 their native range, than to tie up scarce quarantine resources in initial evaluations for polyphagy or in nurturing small, non-viable laboratory colonies. OVERCOMING RESTRICTIONS TO EXPANDED INTERNATIONAL RESEARCH Although international research on new targets, as well as expanded research on current targets, is highly desirable, a number of factors restrict an expansion in intemational research. I briefly review two of these restrictions and offer some suggestions to overcome them. Insufficient Funding for International Research. Current funding for international research to develop biological control agents for invasive weeds is not only far from optimal; it is below critical levels. We lack the financial resources both to launch projects on newweeds and to suc~ssfully address current targets. Significant new funding is seldom available, and current funding is stretched thin. A string of successes in weed biocontrol would stimulate development of further funding; however, few funds are currently available to ensure such future success. The best near-term solution would be to reallocate current resources to increase the likelihood of success for key projects. Fewer, better-funded projects more likely would generate such successes. However, this would mean terminating or delaying projects that appear to offer little chance for success. A weed that has many closely related species native to the area where an agent would be released will require far more effort and funds, and will most likely have fewer acceptable agents, than a weed with few or no close relat~ves In the region of release. Weed targets for which other countries already have developed successful biological control agents should be a high priority for support, because much of the intemational research w~ll have been completed. In 1996, we launched a project targeting Scotch thistle (Onopordum acanthium L. - Asterales, Asteraceae). While this was a new target for North America, the Australians had been conducting international research on Scotch thistle for many years, and, by 1996, had cleared and released several promising species. For the U.S. we could concentrate on evaluation of the most promising of these (Balciunas et a/. 1998). Unfortunately, the first two potential agents evaluated, the weevils Lixus cardui Olivier (Coleoptera, Curculionidae) and Trichosimcalus sp. nov., were unsu~table for release in the US because they readily attacked native American thistles (Balciunas, unpublished data). Thus, the use of transfer agents developed for release in other countries is not a panacea; significant additional testing will likely be necessary, especially if the agents had received only cursory initial screening. For instance, the moth, Cactoblastis cactomm (Berg) (Lepidoptera: Pyralidae), provided spectacular control of Opuntia cactus in Australia, but in the Caribbean, it was found to attack endangered native Opuntia cactus in Florida (Pemberton 1995). Scarcity of Suitable Overseas Laboratories or Collaborators While ecological theory and the successes of biocontrol research suggest that effective biocontrol agents are most likely to be found in the native range of the target weed, few overseas laboratories specialize in biological control research, and they seldom are located near appropriate areas for survey. War, civil unrest, and natural catastrophes, such as a massive earthquake, flood, or volcanic eruption may restrict access to appropriate areas. If sufficient funds are available, stationing an American scientist in the appropriate region is often the most efficient strategy. Research and exploration can be focused on the priorities of the home laboratory and the scientist easily can be relocated when the project is completed or the location proves unrewarding or inhospitable. Since it is difficult to persuade mid- or late-career scientists to commit to a lengthy overseas

7 assignment, young scientists are frequently assigned such projects. Domestic surveys of natural enemies already present for the weed in its new range will familiarize the scientist with the target host and appropriate collecting techniques, and will help himlher to discr~minate among types of damage to the target before helshe goes overseas. It will also allow a supervisor to assess the capabilities of the scientist before assignment to a distant, foreign location. When lack of funds or staffing constraints prevent assignment of a staff scientist, local scientists may be contracted to conduct the desired research Although salaries and research costs are likely less, more supervision and communication are required to assure successful completion of the project. The supervisor should plan annual slte vislts and the local sclentlst should vlslt the US laboratory to better understand the status of the pest and its biology where it is invasive and to interact with U.S. cooperators. When local biological control experts are available, their collaboration can facilitate a successful project considerably to the benefit of both cooperatinglaboratories.7for example, Stefan Neser, at South Africa's Plant Protection Institute, has contributed substantially to the search for potential biological controls for Cape Ivy (also known as German ivy, (Delairea odorata Lemaire, synonym Senecio mikanioides - Asterales, Asterales)) in its native home. With his guidance this project quickly compiled a complete list of herbivores and began evaluations of some of the most promising (Balciunas 2000a) If local scientists are unavailable, trained scientists from a third country may be hired to conduct the research in the desired region. USDA-ARS maintains biological control laboratories in Australia, Argentina, and France and their staff regularly conduct surveys in areas far distant from their laboratories. Likewise, biological control specialists from CAB1 Bioscience, based in London and Switzerland, can be contracted to conduct research almost anywhere. However, those organizations may require reimbursement for all costs, including salaries and overhead. Some projects rely on short exploration trips by staff scientists to the native range of the target host to produce likely candidates for quarantine research. I do not recommend this approach because it is not an efficient use of scarce quarantine resources and because it is less likely to produce effective biological control agents. RECOMMENDATIONS FOR IMPROVING OVERSEAS BIOCONTROL RESEARCH Growing concern about the safety of biological control, coupled with the need for more biocontrol successes mandate that international research be appropriate and efficient. Since research funds are scarce, it is also important that international research not only be productive in the development of new biocontrol agents, but also that agents are successful at limiting the spread or impact of the target plant. The following recommendations are made for conducting overseas biological control research that is both efficient and effective. Invest in long-term research. Overseas research can be divided into two categories: 1) opportunistic, short-term forays, and 2) long-term research. While I sometimes dismiss short-term forays as "grab-andrun", there will always be a role for quick studies. Frequently, the best sites for intensive surveys and long-term research cannot be determined from the literature making personal inspection of potential long-term study sites necessary. For example, because the native range of hydrilla is broad comprising the tropical parts of Asia, Australia, and Africa, I made three, 6-month trips between , repeatedly collecting natural enemies in these regions (Balciunas 1985). Northern Australia was selected as the best location for long-term research on several potential agents.

8 However, projects that rely solely on short trips to the native range of the target plant to supply potential agents and preliminary data are (in my view) 'penny-wise and pound foolish ' When untested agents are only sporadically available, their evaluation in quarantine will proceed slowly. Only the most easily collected and reared are likely to receive sufficient evaluation to support a release request. This approach gambles that a suitable agent w~ll be found before funds and interest in the project fall below critical levels. By contrast, long-term projects can complete the extensive surveys necessary to document completely the natural enemies of the target host. A short list of potential agents can then be prepared and methodically evaluated, both in the field and in quarantine. For example, a 5-year survey of melaleuca (Melaleuca quinquenewia (Cav.) Blake - Myrtales, Myrtaceae) trees in Australia yielded over 400 herb~vores (Balc~unas et a/. 1995), we were able to recommend nearly 30 as deserving further study. Once an overseas laboratory is established, host-specificity testing-can usiualy be conducted far more easily in the native host range than under the restricted, containment conditions of a quarantine facility. Extensive host range tests overseas eliminate inappropriate agents, and speed up the quarantine testing for good agents. Emphasize Field Research Overseas. While laboratory host-range tests conducted in the native host range are desirable, field evaluations of the host range are even more valuable. In Australia, we routinely not only tested the host range of a potential agent under laboratory conditions, but also regularly conducted field surveys of related species and other potential hosts for these same insects (Balciunas et a/. 1994, 1995, 1996). These field data were critical clarifying ambiguous laboratory tests (such as a low reproduction rate on a non-target host) and eventually in gaining release approval for agents that would have been eliminated otherwise. Conduct lwore Research on the Efficacy of Potential Agents. Most practitioners of weed biocontrol feel that an agent is safe if it has a negligible impact on non-target species. However, ecologists are now finding that some of these presumably safe agents can have deleterious ecological impacts. For example, gall flies (Urophora spp. - Diptera, Tephritidae) released to control some knapweeds have become extremely abundant on the knapweed target, but have failed to reduce the knapweed populations. Fortunately, there has been no evidence of a direct impact on non-target plants. However, there is now good evidence that field mice (Pemmyscus sp. Rodentia, Rattidae) are using the abundant overwintering Urophora pupae as their primary winter food, and that this has led to markedly higher populations of field mice (Pearson et a/. 2000). To me this confirms the need to emphasize an agent's efficacy as much as we do its safety. An ineffective agent not only can cause unpredictable changes to the food web and the environment, but its development also wastes scarce biocontrol resources that could have been devoted to better agents. Determination of probable impact is difficult to do in the lab, but sometimes possible under field conditions overseas. In Australia, we demonstrated that Insects at natural, ambient levels, qulckly inhibit growth of Melaleuca saplings by comparing the growth rates of saplings that had been sprayed with insecticides, with those that had not been sprayed (Balciunas and Burrows 1993). Conduct More Research on the Biology and Ecology of Target Weed in its Native Range. In its native range, the target weed is frequently innocuous and sometimes uncommon; almost always little known about its biology and ecology. Research in the native range of

9 the weed could reveal the weak points in its life cycle and allow us to choose more effective agents. Better knowledge of the weed's distribution and environmental requirements in its native range can help us predict additional localities that are susceptible to invasion (Balciunas and Chen 1993). Adhere to International Standards for Research in Host Countries Overseas researchers must familiarize themselves with the rules and regulations for collecting, testing, and shipping specimens in each of the countries that they vislt. Failure to do so may lead to unpleasant outcomes, not only for them and their project, but to scientists who follow. Recently, I helped to formulate a Code of Best Practices for workers in the field of biological control of weeds. In July 1999, delegates attending the Xth lnternational Symposium-for Biological Control of Weeds ratified this Code (Balciunas 2000b). Like other practitioners, overseas researchers should adhere to the principles outlined in the Code (Table 1). We are receiving increased scrutiny from ecologists and the general public. Adherence to the Code not only will make our subdlsclpllne safer, but will assure its greater acceptance by the public. Document Findings and Failures. Each weed biocontrol project may require decades of research and turnover of staff is inevitable. Likewise, old targets may receive new attention, especially when they invade new regions. Thus old research is valuable to new scientists. While all scientists have an obligation to document their research, this is especially critical in our discipline. Much research may be repeated because the original findings, including failures, were not documented adequately in accessible literature. While refereed journals are preferred. symposium and conference proceedings are a good outlet for data and observations that are of local interest. ACKNOWLEDGEMENTS I thank the organizers for allowing me to share these personal observations. LITERATURE CITED Balciunas, J. K Insects and other macroinvertebrates associated with Eurasian watermilfoil in the United States. Technical Report A U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS. 87 pp. Balciunas, J. K Final report on the overseas surveys ( ) for insects to control hydrilla. Technical Report A U.S. Army Engineer Wateways Experiment Station, Vicksburg, MS. 60 pp. Balciunas, J. K. 2000a. Biological control of Cape ivy project reaches milestone. CalEPPC News. pp Balciunas, J. K. 2000b. A proposed Code of Best Practices for classical biological control of weeds. pp , In: N. R. Spencer (ed.), Proc. X Int. Symp. Biol. Control of Weeds, 5-9 July 1999, Bozeman, MT. Montana State University, Bozeman, MT.

10 Balciunas, J. K, and D. W. Burrows The rapid suppression of the growth of Melaleuca quinquenentia saplings in Australia by insects. Journal, Aquatic Plant Management 31 : Balciunas, J. K., D. W. Burrows, and M. F. Purcell Field and laboratory hostranges of the Australian weevil, Oxyops vitiosa (Coleoptera: Curculionidae), a potential biological control agent for the paperbark tree, Melaleuca quinquenervia. Biological Control 4: Balciunas, J. K., D. W. Burrows, and M. F. Purcell Australian insects for the biological control of the paperbark tree, Melaleuca quinquenervia, a serious pest of Florida, u.s.a., wetlands. pp , ~n: E. ~ S. Delfosse and R. R. scott (eds.) ~~~ Proc. Vlll Int. Symp. Biol. Control of Weeds, 2-7 February 1992, Lincoln University, New Zealand. CSlRO Publishing, Melbourne, Australia Balciunas, J. K., D. W. Burrows, and M. F. Purcell Comparison of the physiological and realized host-ranges of a biological control agent from Australia for the control of the aquatic weed, Hydrila verficillata. Biological Control 7: Balciunas, J. K. and T. D. Center Preliminasy host specificity tests of a Panamanian Parapoynx as a potential biological control agent for hydrilla. Environmental Entomology 10: Balciunas, J. K., K. Chan, K. Do, M. Pitcairn, and D. Isaacson Host specificity testing of Lixus spp. for biological control of Scotch thistle. pp , In: (D. Woods ed.), Biological Control Program Annual Summary, California Dept. Food & Agriculture, Plant Health and Pest Prevention Services, Sacramento, CA. Balciunas, J. K. and P.P. Chen Distribution of hydrilla in northern China: implications on future spread in North America. Journal, Aquatic Plant Management 31: Balciunas, J. K. and M. C. Minno Quantitative survey of the insects and other macrofauna associated with hydrilla. Miscellaneous Paper A U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS. pp Balciunas, J. K. and M. C. Minno Insects damaging hydrilla in the USA. Journal, Aquatic Plant Management 23: Pearson, D. E., K. S. McKelvey, and L. F. Ruggiero Non-target effects of an introduced biological control agent on deer mouse ecology. Oecologia 122: Pemberton, R. W Cactoblastis cactorum (Lepidoptera: Pyralidae) in the United States: An immigrant biological control agent or an introduction of the nursery industry? American Entomology 4:

11 Table I. Code of Best Practices for Classical Biological Control of Weeds (as approved July 9'" 1999, by the delegates to the X International Symposium on Biological Control of Weeds, Bozeman, Montana) Ensure that the target weed's potential impact justifies release of nonendemic agents Obtain multi-agency approval for target Select agents with potential to control target Release only safe and approved agents Ensure only the intended agent is released Use appropriate protocols for release and documentation Monitor impact on target Stop releases of ineffective agents, or when control is achieved Monitor impacts on potential non-targets. Encourage assessment of changes in plant and animal communities Monitor interaction among agents Communicate results to public

12 BIOLOGICAL CONTROL OF IW GOURD, COCCINIA GRANDIS (CUCURBITACEAE), IN HAWAI'I Marianne E. Chun Hawai'i Department of Agriculture, 1428 S. King St., Honolulu, HI 96814, U.S.A. corn Abstract. Three insect blologlcal control agents collected in Kenya have beer1 iritruduced ir~tu Hawai'i to combat the exotic weed ivy gourd (Coccinia grandis). The clearwing moth, Melittia oedipus, was released in The larvae of this moth bore into the mature vines and roots of ivy gourd. It is now established in Hawai'i. Two additional agents, which belong to a group known as the African melon weevils, were released in The first, Acylhopeus burkhartorum, forms galls on young shoots. The second, A. cocciniae, mines ivy gourd leaves. Aspects of the project, including host range testing are discussed. Key words: Acythopeus burkhartorum, Acythopeus cocciniae, Coccinia grandis, Cucurbitaceae, Curculionidae, Meliftia oedipus, Sesiidae INTRODUCTION Ivy gourd, Coccinia grandis (L.) Voigt (Violales, Cucurbitaceae), is an aggressive vine that has become a serious weed in lowland areas of Hawai'i, particularly on the island of O'ahu and on the Kona coast of the island of Hawai'i. It is native to Africa and has been present in the Indo-Malayan region of Asia for many centuries (Burkhart 1993, Singh 1990). It is also naturalized in parts of Australia, the Caribbean, the southern United States and several Pacific islands (Linney 1986, Telford 1990). Ivy gourd was first collected on the slopes of Punchbowl, Honolulu, In 1968 and Its presence in the state can probably be attributed to several independent introductions by immigrants from Southeast Asia where ivy gourd is used for food and medicinal purposes (Nagata 1988). Though probably still used to some extent by Southeast Asian immigrants, the general public in Hawai'i has not adopted it as a common food item. Ivy gourd is a dioecious perennial herb with tuberous roots and thick stems, which can grow to several meters in length and up to 12 cm in diameter. These succulent stems allow ivy gourd to survive defoliation caused by occasional outbreaks of powdery mildew and by the recent drought experienced in Hawai'i. It has white flowers and small cucumber-like fruits which turn red when ripe, making them attractive to birds who distribute the seeds to new locations. During the 1970's and 80's, ivy gourd spread rapidly and began to blanket trees and other vegetation. Unlike weeds which flourish at higher elevations and escape widespread notice, the rampant growth of ivy gourd in residential neighborhoods and agricultural' areas prompted many complaints from the general public and the Outdoor Circle, a volunteer organization devoted to maintaining the natural beauty of Hawai'i. The heavy vines hanging from telephone and electrical wires became a problem for utility companies. In addition, ivy gourd fruits were found to be an excellent host of the melon fly, Bactrocem cucurbitae (Coquillet) - (Diptera, Tephritidae). There was particular interest at the time in reducing or eliminating fruit flies to facilitate the export of Hawaiian agricultural crops. Proliferation of ivy gourd increased the melon fly population. In response to the above, there was legislative interest in finding a way to

13 control ivy gourd, and the Hawai'i Department of Agriculture (HDOA) began work on the project. EXPLORATION The vines and tuberous roots of ivy gourd were unresponsive to widespread application of herbicides, and mechanical management was prohibitively expensive. Consequently, the decision was made to look for biological control agents In 1990, exploration had been planned for Southeast Asia to look for natural enemies of the insect pests Thrips palmi Karny (Thysanoptera, Thripidae) and the banana aph~d Pentalonia nigronervosa Coquerel (Homoptera, Aphidae). Ivy gourd was added to the list of target species based on literature that considered Asia to be part of its native range and on consultations with Asian scientists who believed effective control agents were present in the region. However, all of the insects and diseases collected during subsequent work in Thailand, Malaysia, and Indonesia were known to attack other cucurbits and therefore were not considered for use in Hawai'i. Two years later, exploration for natural enemies of ivy gourd shifted to Africa, the center of diversity for the genus Coccinia (Singh 1990). New information suggested that C. grandis is native to north central East Africa and perhaps Arabia (C. Jeffrey, pers. comm. to R. Burkhart). It likely moved into Asia in trade centuries ago. The other 29 species of Coccinia are confined to tropical Africa (Singh 1990). A list of collection localities for ivy gourd was obtalned from the Kew Herbarium, London. During the summer of 1992, Burkhart, HDOA exploratory entomologist, collected over 30 species of insects and several pathogens of ivy gourd in Kenya and Tanzania. Other cucurbits were examined and preliminary host range tests were conducted on promising species. Based on these tests and field observations, five insect species and three pathogens were selected as potential biological control agents and sent to Hawai'i for further testing. HOST RANGE TESTING All cucurbits found in Hawai'i were included in host specificity tests on the eight potential biological control agents. These included commercially grown cucurbit crops, naturalized weedy cucurbits, and representative species of the endemic genus Sicyos as listed by Telford (1990). Additional test plants included species in the Order Violales, several plant species of economic importance, and key endemic species that are major components of native Hawaiian ecosystems. Plants other than cucurbits that contain cucurbitacins, secondary plant compounds characteristic of the family Cucurbitaceae (Metcalf and Rhodes 1990), were not tested, since none of the listed species are known to occur in Hawai'i. Early attempts to identify candidate insects met with failure, a problem common to many biological control projects when agents are collected In parts of the world w~th poorly known faunas. Eichlin (1995) identified the sesiid moth just as host range testing was completed. The identity of the two weevils was delayed until a systematist willing to help was located. An inltlal mlsldentlflcation incorrectly placed them in the wrong genus resulting in our selecting the wrong plants for host screening. Eventually, they were described by O'Brien and Pakaluk (1998), and with the names provided, it was possible to apply for release. Further delays were due to the time required for input and approval from multiple state and federal agencies. The length of time required for the process is unpredictable and may vary due to changing procedures and problems within the approving agencies. In the case of this project, it contributed to a three-year gap between the release of the

14 first agent and the last. The possibility of delays due to this unpredictability should be considered during the planning stage of a project, as they may add greatly to the cost and can tie up personnel and quarantine space for long periods of time. RELEASEPHASE Three of the eight African insect species that underwent host range testing were found to be host specific and were released in Hawai'i. The biology of the three insects and release information is presented below. Melittia oedipus Oberthiir (Lepidoptera: Sesiidae). Larvae of this clearwing moth feed inside mature stems and tuberous roots of ivy gourd. Adults are dlurnal, emerging in the mornlng --- and - mating soon thereafter Females lay eggs soon after mating is completed and are most actrve in full sunlight Eggsarelaid singly on all parts of the ivy gourd plant, from ground level to vines covering the tops of trees. Newly hatched larvae bore immediately into the stems and are exposed only briefly. Larval development and pupation all take place within the vine, and adults emerge in two to four months. Other females are attracted to sites w~th previous infestations, and larvae of different sizes are commonly found in close proximity. Repeated attacks cause vines to break and decay. Other insects attracted to the decaying vines, such as the banana moth, Opogona sacchari (Bojer)- (Lep~doptera, Pyralidae), appear to increase the damage. Meljff~a oedipus was first released on the slopes of Punchbowl, O'ahu, in August From that date to August 1999, approximately 21,600 adults and 16,000 larvae were released on O'ahu. The moth is now well established and vines have thinned out substantially Acythopeus burkhartorurn O'Brien (Coleoptera: Curculionidae) This small black beetle is part of a group known as the African melon weevils. Adult females lay their eggs in meristematic tissue at the tips of young shoots. As the shoot elongates, galls form at the juncture of the stem with leaves and tendrils. When mature, the larva excises the proximal end of the gall, causing it to fall from the plant. The larva seals this cut end with plant fibers obtained from the gall lining. It then turns and excises the other end, forming a smooth cylinder, mm in length. Pupation takes place within this protective case, and the adult emerges three to four months later. Burkhart (1993) surmised that the long pupal stage is probably an adaptation for the long dry season in East Africa when suitable host plants are lacking. The adult weevils feed on young ivy gourd leaves but cause only minimal damage. While this species is not capable of killing ivy gourd, the galls are an energy sink and may slow down growth of young vines. It was first released in August 1999 in Waimanalo on the island of Oahu and in December 1999 in Kailua-Kona on the island of Hawai'i. Acythopeus cocciniae O'Brien (Coleoptera: Curculionidae). This weevil is similar in appearance to A. burkhartonrm but is smaller, being only 2 to 2.5 mm in length, versus 5 to 6 mm for A. burkhartorum. A. cocciniae develops as a leafminer in ivy gourd leaves. Developmental time is approximately 33 days from oviposition to adult emergence. The adults also feed on the leaves. Combined damage from larval and adult feeding can be quite severe. Acyfhopeus cocciniae was first released on O'ahu in November 1999 and in Kona one month later. It has been recovered at all release sites on both islands.

15 BIOTIC INTERFERENCE One of the concerns with any potential biological control agent is the likelihood that natural enemies will attack the agent itself. In the case of Meliffia oedipus, there was concern that a moth might not be effective, as lepidopterans in Hawai'i are often heavily attacked by parasitoids. However, a reference to sesiid pest species in North America noted that they are not well controlled by natural enemies (Solomon 1995). In particular, there was no mention of attack by Trichogramma spp., egg parasitoids that have been a limiting factor for many Lepidoptera in Hawai'i. This may be due to the ~lnusually thick chorion of sesiid eggs. In Africa, parasitism of specimens collected by Burkhart was light and only a few specimens of a large braconid, Hyrtanommatium crassum Enderlein (Hymenoptera, Braconidae), emerged from several pupae (Burkhart 1993). Neither this speeies-nofany-congener-s-oscur-inmawai'i and,so-facnone-of--the-field-sollested--~ larvae, or pupae has shown any signs of attack by parasitoids. However, in 2001, a few male eupelmids (Eupelmus sp. - Hymenoptera, Eupelmidae) were reared from fieldcollected eggs. Ants were anticipated predators of immature stages of the moth. Some fieldcollected eggs show signs of predation, and it is probable that ants kill neonate larvae as they emerge from the egg. However, once larvae bore into the stem, they are relatively well protected, as entrance holes are blocked by frass. A factor not considered prior to release was the high rat population present in the Hawaiian Islands. Since the laboratory rearing of M. oedipus is labor intensive and HDOA personnel and laboratory space are limited, initially it was thought that larval releases would be the most efficient means of getting large numbers of moths into the field. Concentrated numbers were placed in close proximity to increase the probability of emerging adults finding mates. This technique was effective at first. However, rats soon discovered this new food source and tore open vines to extract the larvae. The moth, however, became established, but the high rate of predation impeded a rapid population buildup. We therefore switched to releasing adults instead of larvae since female moths can scatter eggs over a wide area and the rats find a lower percentage of the immatures. It is still too early to determine how detrimental natural enemies will be to populations of the two Acythopeus weevils. In Kenya, both weevils were commonly found early in the wet season in May. However, by the beginning of the dry season in September 40-50% of the leafminers, and almost 100% of the gall-formers, were parasitized (Burkhart 1993). A eurytomid (Eurytoma sp. - Hymenoptera, Eurytomidae) and a eupelmid (Neanastatus sp. prob. rufatus Feniere - Hymenoptera, Eupelmidae) were collected from parasitized galls. Neither of these two parasitoid species occurs in Hawai'i. However, Eupelmus cushmani (Crawford) (Hymenoptera, Eupelmidae), has been reared from A. cocciniae on both O'ahu and Hawai'i, and birds appear to be opening A. burkhartorum galls. In addition, there is a likelihood that the melon fly will oviposit in these galls (M. Ramadan, pers. comm.). LITERATURE CITED Burkhart, R. M., Unpublished report on out-of-state travel to Chairperson, Board of Agriculture, Hawaii Department of Agriculture files. March 24, Eichlin, T. D., New data and a redescription for Melittia oedipus, an African vine borer (Lepidoptera: Sesiidae). Tropical Lepidopterist 6:

16 Linney, G., Coccinia grandis (L.) Voigt: A new cucurbitaceous weed in Hawaii. Hawaii Botanical Society Newsletter 25: 3-5. Metcalf, R. L. and A. M. Rhodes Coevolution of the Cucurbitaceae and Luperini (Coleoptera: Chrysomelidae): basic and applied aspects. In: D.M. Bates, R.W. Robinson and C. Jeffrey (eds), Biology and Utilization of the Cucurbitaceae. Cornell Univ. Press, lthaca & London. Nagata, K. M., Notes on some introduced flora in Hawaii. Bishop Museum Occasional Papers 28: O'Brien, C. W. and J. Pakaluk, Two new species of Acythopeus Pascoe (Coleoptera: Curculionidae: Baridinae) from Coccinia grandis (L.) Voight (CuTuiitaceae) 3TKenya. -Pmceedings o~f the~entomol0g5~a~i~s0~iety, Waxhing ton.- 100: Singh, A. K., Cytogenetics and evolution in the Cucurbitaceae. In: D.M. Bates, R. W. Robinson and C. Jeffrey (eds), Biology and utilization of the Cucurbitaceae. Cornell Univ. Press, lthaca & London. Solomon, J. D., Guide to Insect Borers of North American Broadleaf Trees and Shrubs. Agriculture Handbook 706. U.S. Department of Agriculture, Forest Service. Washington, DC. 735 p. Telford, I. R. H., Cucurbitaceae. pp , In: W. L. Wagner, D. R. Herbst and S. H. Sohmer (eds), Manual of the flowering plants of Hawaii, University of Hawai'i and Bishop Museum Presses, Honolulu.

17 CLASSICAL BIOLOGICAL CONTROL OF CLIDEMIA HIRTA (MELASTOMATACEAE) IN HAWAI'I USING MULTIPLE STRATEGIES Patrick Conant Hawai'i Department of Agriculture, 16 E. Lanikaula St., Hilo HI 96720, U.S.A. . net Abstract. Biological control of Clidemia hirfa in Hawai'i has been episodical in its application over the last 50 years driven more by economics than by biology. Four phases (mid 1950s, late 19'0~~!at e_1981)s, mid- J1'9QsS) -_aredes_cri bed. _AllbSuttonneewasthe res-u llt_oflobb_y ing-by concerned interests. A number of strategies have been tried over the years and their contribution to the control of C. hirta is examined. Six different insect natural enemies and one pathogen have been released up to the present. Evaluation of effectiveness has been completed for only one of the insects and no study has been made of the combined effects of the agents on the growth or reproduction of the plant. Although better control is still needed in infested natural areas, the two most recently released moths that attack reproductive parts may have good impact potential. Key words: biocontrol, Antiblemma acclinalis, Ategumia matutinalis, Buprestidae, Carposinidae, Cerposina bullata, Colletotrichum gloeosporioides f. s. clidemiae, Liothrips urichi, Lius poseidon, Melastomataceae, Momphidae, Mompha trithalama, Noctuidae, Phlaeothripidae, Pyralidae. INTRODUCTION Biological control of Clidemia hida D. Don (Myrtales, Melastomataceae) in Hawai'i began almost 50 years ago and has had a complex history of periodically active work. A variety of approaches have been employed, ranging from lobbying for funds to employing different release methods for the biocontrol agents. Over the decades, and as support has waxed and waned, time has allowed the testing of a wide variety of strategies. By examining the successes and failures, we can plan future weed biocontrol projects that are better tuned to unique problems inherent in Hawaiian ecosystems and in implementation of biocontrol programs. Nakahara etal. (1992) summarized the history of the classical biological control program against C. hirta, commonly known in Hawai'i as clidemia or Koster's curse. Smith (1992) reported on the spread and ecosystem-altering capacity of this weed. These authors made recommendations regarding biological control of clidemia. l will review these recommendations later, but I especially want to emphasize what we have learned along the way in our efforts to control a well-established invasive forest weed in Hawai'i. A chronological account of the clidemia biocontrol effort shows that this program changed course several times as interest and funding came and went over the years. My purpose here is to show the various strategies tried and how they contributed to the classical biocontrol program for this weed.

18 BIOLOGICAL CONTROL First Phase. Clidem~a was first reported as established in Wahiawa, O'ahu, (Krauss 1954) at a meeting of the Hawaiian Entomological Society. However, at the same meeting, a forester of the Board of Agriculture and Forestry, Mr. Karl Korte, reported seeing it there in Also reported in the meeting were personal observations by C. E Pemberton of a noticeable reduction in clidemia between his visits to Fiji in 1920 and 1937 that he attributed to control by the thrips, Liothrips urichi Kamy (Thysanoptera, Phlaeothripidae). Importation and release of the clidemia thrips in 1953 began the biological control program for clidemia that is still ongoing (Table 1). Importation of the clidemia thrips is an example of what I will call "mail order classical biocontrol". It is a fast-and generallycheap-way to import natural enemies. For obvious reasons, there are some prerequisites to being able to "place the order", such as: 1. A known natural enemy that has somehow shown some potential for biocontrol; and, 2. A reliable, affordable, cooperator where the weed and natural enemy occur. Fulfilling item two is not as easy as it might sound. It is usually not difficult to find cooperators in foreign countries, but it can be very difficult to find one that is both affordable and reliable. The thrips had given good results in Fiji (Simmons 1933) and a cooperator was available. It was not until 1982, however, that Reimer and Beardsley (1989) conducted an evaluation of the effectiveness of the thrips. The insect only occurred in sunny or partly sunny areas and did not affect production of flowers or berries. However, it stunted vegetative plants, causing significant terminal leaf abscission, even killing some plants. Once the thr~ps was released, interest in further biocontrol work waned (perhaps because it was no longer considered a significant weed of pastures and plantations). This is a typical scenario for long-term biocontrol projects in Hawai'i and probably elsewhere. Secand phase. It is unclear what spurred Davis to collect a pyralid leaf roller, Ategumia matutinalis (Guenee) (Lepidoptera, Pyralidae) on clidemia in Puerto Rico and Trinidad, West lndies but it was released in Hawai'i in 1969 (Davis 1972). Perhaps the growing publicity about invasive forest weeds that came with early 1970's environmental consciousness and determined lobbying efforts at the state legislature by the Sierra Club, the Conservation Council for Hawai'i and others gained popular support for control of invasive forest weeds during the mid 70's. The continued spread of clidemia in recent decades (Wester and Wood 1977) has made ~t a hlgh pr~or~ty target. Newspaper articles appeared and chronicled the releases of clidemia natural enemies by members of the Sierra Club and its High School Hikers. Without the determined lobbying efforts ot several people (e.g., Betsy Gagne, Lorrln GIII, Dana Peterson), the dormant clldemia biocontrol program might not have been revitalized. Keeping the broad conservation community informed and involved in natural area weed biocontrol can make a big difference In fundlng allocations. Funding obtained by the lobbying effort and the publicity generated led the governor to issue a mandate requiring the use of available departmental funds to find effective methods of control, including biocontrol. By 1978, the University of Hawai'i

19 and the Department of Land and Natural Resources (DLNR) were involved in clidemia research and control and the Hawai'i Department of Agriculture (HDOA, formerly the Board of Commissioners of Agriculture and Forestry) was designated the lead agency (Nakahara et a/. 1992). Third phase. A classical biocontrol exploration program was proposed by HDOA and implemented in Robert Burkhart conducted a typical exploratory trip of three months duration in South America. A number of natural enemies were sent back but could not be kept alive in quarantine. Dead specimens of each species were retained in the HDOA collection. Insects attacking reproductive parts could not be cultured due to the poor amb~ent light in the 1960's vintage quarantine building. Clidemia plants did not thrive, --- flowers aborted-and fruit dropped. -The-inadequacy of the-quarantinefacilityfor growing certain target weeds through their life cycle led to another change in the approach to clidemia control. Virtually all classical biocontrol exploration done by the HDOA previously was based typically on a 3-month or less collecting trip. In contrast, the 1980 exploratory trip was a 6-month trip to Trinidad jointly funded by DLNR and HDOA. A local technician was hired there and trained to ship insects to Hawai'i after Burkhart left. Unfortunately, for the second time, none survived in quarantine in Hawai'i. Then in 1982, Burkhart set up house-keeping in Trinidad at the Commonwealth Institute of Biological Control (CIBC) for a longer stay to collect, rear and test the specificity of the natural enemies of clidemia. Burkhart was a welcome guest because he had taken natural enemies of crop pests to Trinidad for exchange. On this trip, a new, almost revolutionary approach for HDOA was tried: The host specificity tests were performed outdoors under natural conditions to avoid all the problems associated with the dark and highly artificial quarantine environment. Was this "country of origin" method of exploration effective in this case? Was it worth the cost? To answer the first question, yes it was indeed effective. Regarding cost, this trip was a somewhat special case in that the costs were minimized by exchanging natural enemies for services and by combining funding from other exploratory biocontrol projects he performed simultaneously. This same country-of-origin work today can be quite expensive. In his clidemia work at CIBC Burkhart used two basic approaches: 1) choice and no choice tests in outdoor cages; and, 2) exhaustive sampling of representative taxa of sympatric non-target plants to delineate the natural host range of the more promising natural enemies. His studies identified 14 species that appeared to have potential for Hawai'i (Nakahara et a/. 1992). Two of these, Eurytoma sp. "black" (Hymenoptera: Eurytomidae) and Penestes sp. (Coleoptera: Curculionidae), were found to be of no value (Burkhart 1986, 1988). His tests led to the eventual release of four more species. Within this small complex of insects lie more lessons to be learned from this project. Among the myriad dilemmas facing an exploratory entomologist working alone in a foreign country is "the quick fix vs. the long slow, difficult, but presumably more effective fix" dilemma. The two approaches are not mutually exclusive but the quick fix does tend to favor species that are easy to handle in quarantine and which have not been evaluated as the most effective of the suite of species available. However, an experienced biological control specialist can often choose effective agents after a short visit to the native country of a target weed. The evaluation of all host-specific species for impact and then working out their biology and conduct~ng host screening

20 experiments prior to their introduction into quarantine can be extremely expensive and time-consuming. Administrative pressure to justify spending money out of state as well as the need for success in order to justify the foreign travel are never far from one's thoughts. Lius poseidon Napp (Coleoptera: Buprestidae) and Antiblemma acclinalis Hubner (Lepidoptera- Noctuidae) are examples of the "quick fix". Lius poseidon is a buprestid beetle that mines the leaves in the immature stage while adults are defoliators. Antiblemma acclinalis larvae roll up leaves and feed within. Unfortunately both species are attacked by parasitoids already present in Hawai'~. Mompha trithalama Meyrick (Lepidoptera: Momphidae) and Carposina bullata Meyrick (Lepidoptera: Carposinidae) are examples of the long, slow method. Mompha trithalama larvae feed primarily on the seeds within berries and C. bullata larvae feed primarily-on-flowers,(these rolesoverlap-somewhat). The-formeris-established in Hawai'i but it is too early to determine any impact. The latter has not been established. B~otic interference is a significant problem in biological control programs, particularly in Hawai'i. Its effects have been studied in the Hawaiian program against clidemia. Reimer and Beardsley (1986) found that larvae of the leaf roller (A. matutinalis) were parasitized by 4 species of hymenoptera. Their sampling methods did not include egg or pupal parasitiods, although they did rear out one species of Trichogramma from an egg. Percent parasitization of the larvae was consistently high suggesting that "These high levels of parasitization by parasitoids may be a major and at the very least an important factor contributing to low (A. matutinalis) field populations" (Reimer and Beardsley 1986). Effectiveness of the leaf roller has never been evaluated, but its rarity in the field suggests that it has little impact on the plant. Damage in the field is readily recognized by the rolled up sub-terminal leaves in which the larvae feed. Reimer (1988) found that ants and an anthocorid bug preyed on the thrips and caused significant mortality. The two control agents released and evaluated for biocontrol of clidemia both suffer from biotic interference. Antiblemma acclinalis Hubner (Lepidoptera, Noctuidae), first released in 1995, may be suffering a similar fate since the moth and its damage are rarely seen, even at former release sites. Young larvae feed on leaves at night, and rest under leaves during the day. Third instar and older larvae migrate down to the ground during the day and climb back up to feed on foliage at night (Burkhart 1987). My collections of Lius poseidon larvae produced adults of Chrysocharis parksi Crawford (Hymenoptera: Eulophidae), a purposefully introduced parasitoid of Liriomyza (Diptera, Agromyzidae) leaf miners on vegetable crops. It is possible that other leaf miner parasitoids are attacking this beetle and they may be attacking a Gracillariid moth that has been released to control Myrica faya Aiton (Myricales, Myricaceae). How much biotic interference occurs with other natural enemies released for biocontrol of weeds in Hawai'i? More field collections of immature stages of biological control agents are needed to assess this problem. In fact, it is a significant need in the evaluation of all Hawaiian biocontrol introductions. In 1985, the Hawai'i State Legislature adopted another tactic, the use of a plant pathogen. A leaf spot fungus (Colletotrichum gloeosporioides f. sp. clidemiae Trujillo (Deuteromycotina, Melanconiaceae) from Panama appeared to have good potential (Trujillo, Latterell and Rossi 1986). It was only the second time a pathogen had been used in classical weed biocontrol in Hawai'i, and the first one against a natural-area weed. There always had been considerable resistance to the use of pathogens but the demonstrated potential of the fungus overcame opposition. The fungus is now

21 established on most islands infested with clidemia. Defoliation can be extensive over contiguous areas when weather conditions are favorable (cool, windy and rainy). Its effects on the weed have not been quantitatively evaluated as yet so it is difficult to assess its long-term impact, but it does appear to defoliate and stress the plant at least seasonally. Lius poseidon was approved for release by the Board of Agriculture in early Specimens from each shipment were first sent to Dr. Minoru Tamashiro, University of Hawai'i, to check for pathogen infection of the agents prior to their release. The insect is now established on Maui, O'ahu, Kaua'i and Hawai'i. The effectiveness of neither the leaf feeding adults nor leaf-mining larvae has been quantified. Damage to young plants appears to be greater than to mature plants, particularly in combination with thrips damage. Fourth phase. The clidemia project became dormant again after the release of L. poseidon. The fourth attempt to use biological control began in the mid 1990s. Hurricane lniki (1992) caused extensive damage to forested areas on Kaua'i, which became vulnerable to weed invasion. U.S. Forest Service (USFS) funds became available in 1995 for forest restoration with control of invasive forest weeds a high priority. Since clidemia already infested the wetter low to mid elevation forests there, some of these funds were used to import another natural enemy for clidemia. Anfiblemma acclinalis had been approved for release years earlier but no funds had been available to import it. It was first released in 1995 but remains uncommon, probably due to parasitism. Rearing and release of A. acclinalis was still ongoing in 1998 when USFS Special Technology Development Program funds were obtained to import C. bullata and M. trifhalama. Burkhart had finished all the host specificity tests in Trinidad many years earlier, but the results and petition to release had never been prepared because funding had lapsed. State and Federal approval was obtained for release of both species in 1995 and releases began that year. However, releases were very small and establishment was doubtful. Funding from the U.S. Army coincidentally became available in 1997 for Burkhart to rear both species in Tobago, West lndies and ship them to the HDOA in Honolulu as pupae. Samples were sent to Dr. Gerard Thomas in Berkeley for pathogen diagnosis prior to release. Releases of M. trithalama were made at Schofield Barracks East Range (Schofield-Waikane Trailhead), Lyon Arboretum and Kahana Valley on O'ahu, and at Pohoiki and Waiakea Forest Reserve on the island of Hawai'i. M. trithalama now appears to be established at Kahana Valley and Pohoiki. C. bullata has yet to be recovered, but surveys will continue at all release sites. Redistribution will be made to other islands and other clidemia infestations within islands once either moth is firmly established. FUTURE PROSPECTS The consensus among environmentalists and land managers appears to be that clidemia is still not under adequate control. It is too early to know the effects of the two most recently released lepidoptera (Table 1). No formal impact evaluation studies are underway other than checking for establishment. Importation and release of new agents in the future may warrant consideration. Nakahara et a/. (1992) mention five species (among others) of clidemia natural enemies in Trinidad identified by Burkhart as having potential for biocontrol in Hawai'i. Two of these are lepidoptera that attack

22 both clidemia and Miconia sp. (Melastomataceae) flowers. The remaining three are a eurytomid gall-forming wasp that attacks the berries, an unidentified cecidomyiid midge that attacks flowers and an unidentified stem-boring cerambycid beetle, which proved difficult to work with. All three of these might be at low risk of biotic interference and the former two could be useful additions to the complex of natural enemies now established. However, the use of plant pathogens should be reconsidered now that HDOA has a quarantine facility with a plant pathologist on staff. Pathogens have some advantages over insects: they can be tested more quickly than insects, take up less space and are, in general, easier to propagate. Table 1. Natural enemies of Clidemia hirta (Melastomataceae) released in Hawai'i. Species Liothrips urichi Ategumia matutinalis Colletotrichum gloeosporioides f. s. clidemiae Lius poseidon Antiblernma acclinalis Mompha trithalama Carposina bullate Part of plant attacked TERMINALS LEAVES LEAVES LEAVES LEAVES FLOWERSIFRUIT FRUITIFLOWERS Year Released Using biological control against any plant in the family Melastomataceae in Hawai'i could also be beneficial to the control of clidemia. Since virtually all of these species are known to be weeds in Hawai'i, host specificity of a biocontrol agent needs only to be limited to the family of the host plant. The biocontrol program for Miconia calvescens could conceivably aid in control of clidemia as well as other melastornataceous weeds in Hawai'i. SUMMARY OF STRATEGIES USED AND LESSONS LEARNED IN CLlDEMlA BIOCONTROL 1) Education and publicity can lead to popular support and funding of individual programs. 2) "Mail order" natural enemies (biocontrol agents readily available from a foreign cooperator) can be a quick method of importing agents, if a reliable cooperator at a reasonable cost can be found. 3) Traditional short-term (three months or less) classical biocontrol exploration can be useful if natural enemies that can be reared easily in quarantine are found. 4) Long-term work in country of origin by a Hawai'i-based explorer can be effective but may be expensive. This strategy allows host-range and specificity tests to be done under natural conditions. 5) The advantages and disadvantages of "Fast-tracking" easy-to-rear foliar feeders vs longer-term efforts for harder-to-rear flowerlfruit feeders should be evaluated 6) The likely impact of biotic interference should be evaluated. Leaf feeding lepidoptera with exposed diurnal larvae may have lower

23 probability of success due to biotic interference by parasitoids. Leaf mining larvae may also be at risk from parasitoids. 7) Plant pathogens should be considered seriously in any biological control program against weeds. LITERATURE CITED Burkhart, R. M Progress report on exploratory studies on Clidemia hirta in Trinidad, West Indies. June 1984-June Hawai'i Department of Agriculture files, Honolulu. 52 pp. Burkhart, R. M Supplemental report on the host range and life history of Antiblemma acclinalis Hubner (Lepidoptera: Noctuidae). Hawai'i Department of Agriculture files, Honolulu, Hawai'i. 13 pp. Burkhart, R. M Supplemental report (Part II) of investigations in Trinidad of insects feeding on the flowers and berries of Clidemia hirta. June 1985-June Hawaii Department of Agriculture files, Honolulu. 51 pp. Davis, C. H Recent introductions for biological control in Hawaii. Proceedings, Hawaiian Entomological Society 21 : Krauss, N. H Notes and Exhibitions. Proceedings, Hawaiian Entomological Society 1 5: Nakahara, L. M., R. M. Burkhart and G. Y. Funasaki. (1992). Review and status of biological control of clidemia in Hawai'i. pp , In: C.P. Stone, C.W Smith and J.T. Tunison (eds.), Alien plant invasions in native ecosystems of Hawai'i: management and research. University of Hawai'i, Department of Botany, Cooperative National Park Resources Studies Unit, Honolulu. Reimer, N. J Predation on Liothrips urichi Karny (Thysanoptera: Phlaeothripidae): a case of biotic interference. Environmental Entomology 17: Reimer,N-J-and J7W,-Bea~dsley~l 986.-Some-notes-on-parasitizationd--- - Blephatomastix ebulealis (Guenee) (Lepidoptera: Pyralidae) in Oahu Forests. Proceedings, Hawaiian Entomological Society 27: Reimer, N. J. and J. W. Beardsley Effectiveness of Liothrips urichi (Thysanoptera: Phlaeothripidae) introduced for biological control of Clidemia hirta in Hawaii. Environmental Entomology 18: Simmons, H. W The biological control of the weed Clidemia hirta D. Don in Fiji. Bulletin of Entomological Research 24: Smith, C. W Distribution, status, phenlology, rate of spread, and management of clidemia in Hawai'i. pp , In: C.P. Stone, C.W Smith and J.T. Tunison (eds.), Alien plant invasions in native ecosystems of Hawai'i: management and

24 research. University of Hawai'i, Department of Botany, Cooperative National Park Resources Studies Unit, Honolulu. Trujillo, E. E., F. M. Latterell and A. E. Rossi Colletotrichum gloeosporioides, a possible biological control agent for Clidemia hirta in Hawaiian forests. Plant Disease 70: 974. Wester, L. and H. 6. Wood Koster's Curse (Clidemia hirta), a weed pest in Hawaiian Forests, Environmental Conservation. 4:

25 HOST SPECIFICITY TESTING OF BIOCONTROL AGENTS OF WEEDS Tim A. Heard CSlRO Entomology, Long Pocket Laboratories, 120 Meiers Rd, lndooroopilly 4068, Brisbane, Australia Abstract. A range of test designs is available to biocontrol practitioners. Their suitability depends on the biology of the potential agent being tested. Tests are conducted on many aspects of the biology of agents including oviposition, adult feeding, larval feeding, larval development, adult longevity and fecundity, and field utilization under natural conditions. Commonly used designs are choice, no-choioe and choice-minus-target, in parallel or in sequence. Many behavioral factors affect the results of host specificity testing. These factors can be divided into 1. the sequential behavioral responses to host plant cues, 2. learning and 3. the effects of time-dependent factors. These behavioral effects can be complex, can be caused by a variety of mecnanlsms and can produce opposlng effects. Biocontrol workers should be familiar with the behaviors that affect the results of these tests and apply their knowledge of them appropriately. That is, biocontrol workers responsible for host specificity testing should recognize that they are applied behavioural biologists as well as applied ecologists. Keywords: host range testing, risk assessment, applied behavioral theory. INTRODUCTION Host specificity testing is a critically important step in the process of introducing natural enemies for classical biological control. Most direct non-target effects can be predicted if a sound understanding of the host specificity of potential biocontrol agents is gained. Host specificity testing provides the basic information upon which the safety of a proposed biocontrol agent can be assessed. Sound host specificity testing also prevents another problem-the rejection of safe and potentially effective agents because of an inability to prove their high level of specificity. Hence in host-specificity testing, we are trying to avoid false results, both false positive results and false negat&-cm=.-ealse positives refer to the attack of a plant in the test when there is no potential for attack on that plant in nature. That is, the host range is over-estimated. False negative results indicate no attack in the test where there is potential for attack in the field; the host range is thereby under-estimated (Marohasy 1998). In this paper, I review experimental designs used in host-specificity testing of potential biological control agents. I then list some of the more important behavioral and biological factors that affect the validity of tests and discuss the strengths and limitations of the various tests used in light of these behavioral and biological factors. I do not cover the topic of the selection of plants for the host test list as this is well covered in the literature. This talk focuses on arthropod agents of weeds but the results and analysis are applicable to host specificity testing of predators and parasitoids of arthropod pests. Host specificity testing of pathogens will continue to rely on inoculation of test plants because spore dispersal of most potential weed control agents is passive. However, where insects are the vectors of pathogens, appropriate testing must account for insect behavior.

26 REVIEW OF METHODS USED IN HOST-SPECIFICITY TESTING Aspects of biology examined Many experimental approaches to determination of the host range are used. Various experiments examine aspects of host selection and use by agents as indicated by oviposition, adult feeding, larval feeding, larval development, adult longevity and fecundity. Some tests are conducted in the field and determine which hosts are used under natural conditions (Heard & van Klinken 1998). Test designs Tests are traditionally divided into two designs-- choice and no-choice--depending on whether the organism can select from a range of species or is restricted to a single species. In a no-choice test, groups of insects are placed on each plant species in separate arenas such as cages, jars, petri dishes, etc (Figure 1). In choice tests, insects are located in arenas in the presence of a choice of plant species including the target weed (the control). A separate category of design is the choice-minus-target (or choice-minus-control) test that includes a choice of test plant species excluding the target. The results of no-choice tests allow us to predict the realized field host range in the absence of the target weed. Choice tests do the same in the presence of the weed. Both of these scenarios are possible in nature so both types of tests have a [.ole. No-choice and choice-minus-target tests are subdivided into sequential or simultaneous depending on whether the target species and the test species are offered in sequence to the same insects or at the same time to different insects. If done simultaneously, separate groups are placed on test plants at the same time. Sequential tests differ in that the same group of adults is moved from plant to plant. In the sequential tests, the insects are not naive but have experience of other plants. The significance of this will be discussed in the section on learning below. Choice-minus-target tests are useful and perhaps under-used designs. A powerful, efficient test with few behavioral shortcomings is one in which the target weed is offered as no-choice and done simultaneously with the choice of test plants. We can gain a clearer picture of the suitability of different host specificity tests by viewing tests as a combination of biological responses measured under different experimental designs (Table 1). The test design used depends on the biological Table 1. Frequency of occurrence of test designs versus biological response rneasure~sdetefntinedfr0ma-literatu~viewof38 paperspublishe&avecthepast 20 years (Heard 8 van Klinken 1998). No- Choice Choice- Total choice minus-target Oviposition ~dult feeding Larval feeding Larval development Adult longevity 9 9 Adult fecundity 7 7 Field utilisation (from surveys) 5 5 Field utilisation (from open-jield tests) 4 4 Total

27 response under investigation. Tests on larval development, adult longevity and fecundity can be only of the no-choice design, while field-survey and open field tests are necessarily choice tests under natural or semi-natural conditions. Other responses (oviposition, adult feeding and larval feeding) may be addressed in any of the test designs. From the final column, we see that tests commonly examine oviposition and larval development. In many studies these two tests are done together for a particular agent to assess the behavioral preferences of adults (acceptability) and the suitability of the plant for larval development and production of viable adults. If both responses are measured together, results may be confounded. If, for example, the eggs are laid internally in the plant and not easily scored, larval presence or damage or adult emergence are the only indications of oviposition In this case, one cannot discern whether a negative score is the result of unacceptability of the host for oviposition, or unsuitability for larval development, or both. When these two responses are measured separately, some practitioners subject all test plants to both tests. Others only subject species accepted in oviposition tests to larval development tests. A third option is to assess larval development on all plant species and to assess suitability for oviposition only on those species that support larval development. Because most immature insects have limited dispersal ability, larval development trials are most important for plant species on which oviposition occurs. Withers (1999) recommends that all test plants be subjected to both tests to fully assess risk. Larval development tests are prone to false positive results, because the developmental host range is often wider than the range of plants used in nature. Hence by themselves, larval development tests can result in the rejection of safe agents. Sometimes, when tests assessing oviposition behavior are difficult (e.g. in many Lepidoptera and Hemiptera), larval development tests cannot be done in conjunction with oviposition tests. Larval development tests are still routinely used in the USA where they often are called starvation tests. Where standardized testing procedures are required, it is the only test that can be applied to nearly all agents. Adult feeding tests are commonly investigated. These trials are restricted to species that feed destructively and so are not used with those species that do not feed (e.g., Cecidomyiidae) or that feed non-destructively (e.g., most Lepidoptera, Bruchidae, Tephritidae). Adult feeding may not be important per se, in that only minimal damage can be done to plants if larvae cannot develop on them. However, even cosmetic damagecanaffect publicperception-otbiocon~rol-results.~i~dia,asmall_f~ feeding on sunflower by Zygogramma bicolomta Pallister (Coleoptera: Chrysomelidae) a biocontrol agent of Parthenium hysterophorus L. (Asterales, Asteraceae) has almost shut down the use of biocontrol agents to control weeds in that country. Adult fecundity tests (also known as oogenesis tests) examine the ability of a plant to support egg production. Their use is restricted to insects that depend on adult feeding for continued egg production (Schwarzlaender et a/. 1996). They differ from adult feeding or oviposition tests that test the acceptability of a host. Adult fecundity tests examine both the acceptability of the food (behavior) and its suitability for egg maturation (physiology). These tests are relevant only for plant species that adults accept for feeding. Adult longevity tests often are performed also with adult fecundity tests. Field surveys and open-field tests are being used only occasionally but increasingly. In open-field tests, the test plants are placed In the field In the nat~ve

28 range of the agent. Sometimes the local abundance of agents is increased. The absence of a cage in these tests allows the assessment of all aspects of the host selection process, so the results are more likely to predict the realized host range when the agent is introduced into a new geographic range. Field surveys are fundamentally the same as open-field tests, but in the latter plant spatial arrangements and agent densities are not manipulated. A STRATEGY FOR HOST-SPECIFICITY TESTING This array of test combinations must be integrated into an overall experimental strategy. More than one test usually is needed to determine host specificity. The sequence in which tests are employed may vary; field tests can be done early, for preliminary screening, or late, for clarification of equivocal lab results. Several tests may be applied to all plant species on a list or one type of test can be used to eliminate plants from further testing before a second test is applied to the reduced set of plants. Alternatively a subset of plants may be tested initially to decide whether the agent is sufficiently promising to justify further testing. Some attempts have been made to combine the results of several tests to calculate an index of plant suitability - a bottom line (Wan & Harris 1997). This is a step towards a risk assessment approach, in which the risk to non-target plant species is quantified. For example, the probability that a plant is accepted for oviposition multiplied by probability of larval development estimates the probability of an adult producing a pupa on the host plant. All plants on the test list should be tested for both these components to make comparable calculations. Some practitioners resist this approach because it would not seem necessary to test the suitability of a plant for larval development if it is never accepted for oviposition. (Withers 1999). It may not be desirable to develop a formulaic approach to host specificity testing. The current lack of standardization in the type of test used reflects the unique aspects of the biology of each agent as well as associated practical considerations. BIOLOGICAL FACTORS AFFECTING TESTING STRATEGIES Insect behavior involved in host selection is expressed during the conduct of tests and can influence the results. Understanding the host selection behavior of potential agents is the key to more effective host specificity testing. Sequential behavioral responses to host plant cues There is a long held and widely accepted recognition that insects use a sequence of behavioral responses to cues in host selection. The sequence of steps in host selection includes habitat location, host location, host acceptance, and host utilisation (Keller 1 999). Consideration of the sequential behavioral steps to host selection raises a number of issues that have consequences for host specificity testing. Possibly the most important point is inability to express the early steps of the host selection sequence in many experimental arenas If each step eliminates a certain number of potential hosts, then the removal of that step from a host test may generate false positive results. This process has been demonstrated with Drosophila magnaquinaria (Diptera, Drosophilidae) (Kibota & Courtney 1991). In nature, this insect first selects its habitat (low lying areas); within that habitat it then selects its only natural host (skunk

29 cabbage). If the insect is confined to a cage, it selects many more plant species for oviposition than it does in nature, producing false positive results. Testing for host range in insects such as this should incorporate this early step in the host selection behavior. Use of larger, more natural arenas, field surveys and open-field testing may alleviate this problem. Less well-known methods to minimize the false positives in lab tests include the use of wind tunnels or olfactometers, or simply provision of good airflow through cages. Long-distance cues used in host location often rely heavily on olfaction and the still air in cages does not allow for the upwind response of insects to olfactory cues. If a potential agent gives a negative response to a plant species in an olfactometer, that plant species may be eliminated as a potential host. That plant species may have been accepted when the insect was confined to it in a cage. Increased airflow through cages may provide a simple solution to allow some insects to include olfactory cues in the host selection process (Keller 1999). It is thus important to understand the critical steps in the host selection process for the insect being tested; and include these steps in the test design. Some insects are very specific in their habitat choice, e.g. the Drosophila on skunk cabbage. Others, such as many Lepidoptera, use distant, pre-alighting host plant cues. Still other insects, such as Aphis fabae Scop. (Homoptera, Aphididae), passively locate plants, but show high specificity for chemo-tactile cues such as surface chemicals. Insects that depend on pre-alighting host plant cues probably will not be tested accurately in small arenas, but insects that passively locate hosts can be. Learning Learning can be defined as the modification of behavior due to the effects of prior experience. The effects of experience (learning, memory and forgetting) are important behavioral components of the host-selection process. Hymenopterous parasitoids are well known for their abilities to learn. A smaller proportion of phytophages are known to learn; they include Lepidoptera (adults and larvae), tephritid flies, Orthoptera and Coleoptera (Papaj & Lewis 1993). A number of mechanisms are involved in learning; I will examine two-- habituation and induction of preference. Habituation is the decrease in response to a stimulus with repeated exposure to that stimulus. Habituation to feeding deterrents is a common phenomenon in which an insect initially is deterred but, after more exposure, begins to accept a plant. Habituation can have consequences for host specificity testing. For example, insects -mayhabituateto-deterre~ts-~h~~~~stfhtr~~g~peated-sonta&-while~onfine~withthem in cages resulting in eventual acceptance of those plants. False positive results are produced in such cage tests. In nature, the insects are likely to leave the plant before habituation occurs. lnduced preference is the effect of experience on changes in food or oviposition preferences. For example, in many species, newly hatched larvae will only accept plants they first experience for further feeding. lnduced oviposition and adult feeding preferences are influenced by early experience in many insects. For example, an adult may respond to cues she learned when she emerged from her pupa to show oviposition or feeding preference for the same species of plant on which she emerged. lnduced larval feeding preferences can lead to false negative results, if insects begin their feeding on the target weed and are then transferred to test species. Other mechanisms of experience and learning can affect the results of host specificity tests (Marohasy 1998, Heard, 2000). In general several tactics help avoid

30 unwanted consequences. First, whenever possible use naive insects that have no experience of any plants. Second, be aware of the false results certain tests can generate and incorporate this information into their interpretation. Third, use different test designs and compare results to assess which mechanisms may be operating. Time-dependent effects Time-dependent effects are reversible changes in the responsiveness of an organism to a potential host resulting from food or oviposition site deprivation. As an insect becomes more deprived it may become more likely to accept lower ranked hosts. A hungry insect may feed on a wider range of hosts than a satiated one. An insect that has recently laid an egg may reject a lower ranked host for a considerable period (Withers et a/. 2000). The main consequence of this effect is a false negative result in choice tests. For example, Bruchidius villosus (F.) (Coleptera, Bruchidae), a seed feeder introduced into New Zealand and Australia against broom, is attacking tagasaste (Chamaecytisus palmensis), a non-target plant in New Zealand. This attack on tagasaste does not represent a host range expansion, but a failure of host specificity testing to predict field host range (Fowler eta/. 2000). Testing relied on choice tests alone and under the conditions of this test, tagasaste was not attacked. Choice tests can generate false negative results due to time-dependent effects. Insects may never reach a sufficiently deprived state in the presence of the host plant to accept lower ranked hosts. However, when in a no-choice situation, as happens in the field because tagasaste fruits are available before broom, the insect may oviposit and feed on non-target species A recent review of open-field testing has shown that this effect can take place under natural conditions (Briese 1999). The results of open-field tests vary depending on the experimental design. For example when the density of test plants is too low, false negatives results are obtained because the insects never reach a sufficiently deprived state. To minimize these consequences, temporal patterns of feeding and oviposition should be understood for each insect. This information should be incorporated into the design of the host specificity tests. Second, no-choice trials should be continued for the whole of the insect life to ensure that the insects become sufficiently deprived to accept lower ranked hosts. Third, in open-field tests and field surveys, the target plant should be removed to achieve a deprived state in insects. I thank Stephen Hight and Julie Denslow of the USDA Forest Service, for providing the opportunity to visit Hawai'i to present this paper. The useful comments of Lindsay Barton Browne, Mic Julien and an anonymous reviewer improved the manuscript. LITERATURE CITED Briese, D Open field host-specificity tests: Is "natural" good enough for risk assessment? pp , In: Host Specificity Testing in Australasia: Towards Improved Assays for Biological Control. T. M. Withers, L. Barton Browne and J. Stanley (eds), Scientific Publishing Queensland Department of Natural Resources, Brisbane.

31 Fowler, S. V., P. Syrett, and P. Jarvis Will the Environmental Risk Management Authority, together with some expected and unexpected effects, cause biological control of broom to fail in New Zealand? pp , In: Proceedings of the ldh International Symposium on Biological Control of Weeds. Bozeman, Montana, USA, July 4-14, N. Spencer and R. Nowierski (eds). Montana State University, Bozeman? Heard, T. A., Concepts in insect host-plant selection behavior and their application to host specificity testing pp 1-10, In Host-specificity testing of exotic arthropod b~ological control agents: the biological basis for improvement in safety. R. G. Van Driesche, T. A. Heard and A. McClay (eds), Forest Health Technology Enterprise Team, USDA Forest Service, Morgantown, West Virginia Heard, T. A. and R. D. Klinken van An analysis of designs for host range tests of insects for biological control of weeds. pp , In: Pest Management - Futuns Challenges, Sixth Australasian Applied Entomology Research Conference, Vol 7. M. P. Zalucki, R. A. I. Drew, and G. G. White (eds), The University of Queensland Printery. Brisbane. Keller, M. A Understanding host selection behaviour: the key to more effective host specificity testing. pp In: Host Specificity Testing in Australasia: Towards lmproved Assays for Biological Control. T. M. Withers, L. Barton Browne and J. Stanley (eds). Scientific Publishing Queensland Department of Natural Resources, Brisbane. Kibota, T. T. and S. P. Courtney Jack of one trade, master of none: host choice by Drosophila magnaquinaria. Oecologia 86: Marohasy, J The design and interpretation of host-specificity tests for weed biological control with particular reference to insect behaviour. Biocontrol News and Information 19: 13N-20N. D. R. Papaj and A. C. Lewis Insect Learning: Ecology and Evolutionary Perspectives. Chapman and Hall, New York. Schwarzlaender M, H. L. Hinz, and R. Wittenberg Oogenesis requirements and weed biocontrol: an essential part in host-range evaluation of insect agents or just wasted time? pp , In: Proceedings of the 9th international symposium on biological control of weeds, January V. C. Moran and J. H. Hoffmann (eds). University of Cape Town, Rondebosch. Wan F. H. and P. Hanis Use of risk analysis for screening weed biocontrol agents: AMca carduomm Guer. (Coleoptera: Chrysomelidae) from China as a biocontrol agent of Cirsium arvense (L.) Scop. in North America. Biocontrol Science and Technology 7: Withers, T. M. (1999) Towards an integrated approach to predicting risk to non-target species. pp , In: Host Specificity Testing in Austmlasia: Towards lmproved Assays for Biological Control. T. M. Withers, L. Barton Browne and J. Stanley

32 (eds), Scientific Publishing Queensland Department of Natural Resources, Brisbane. Withers, T. M., L. Barton Browne and J. Stanley How time-dependent processes can effect the outcome of assays used in host specificity testing. pp. 41, In: Hostspecificity testing of exotic arthropod biological control agents: the biological basis for improvement in safety. R. G. Van Driesche, T. A. Heard and A. McClay (eds), Forest Health Technology Enterprise Team, USDA Forest Service, Morgantown, West Virginia.

33 Figure 1. Some test designs used in host specificity testing of biocontrol agents. Circles represent plants, squares represent cage, and arrows represent the addition of a group of insects. No-choice sequential Choice No-choice simultaneous Choice-minus-target simultaneous b 0 plant 2

34 HOST SPECIFICITY AND RISK ASSESSMENT OF HETEROPERREYIA HUBRICHI, A POTENTIAL CLASSICAL BIOLOGICAL CONTROL AGENT OF CHRISTMASBERRY (SCHINUS TEREBINTHIFOLIUS) IN HAWAI'I Stephen D. Hight U.S. Forest Service, Pacific Southwest Research Station, Institute of Pacific Islands Forestry and University of Hawai'i, Hawai'i Volcanoes National Park Quarantine Facility, P.O. Box 236, Volcano, HI , U.S.A. ~~i~f~t~~~~emaiiv.com Current Address: U.S.D.A., Agricultural Research Service & Center for Biological Control, Room3~OrPerry-PaigeBl;lildi~g~S~1;1th~FI~rid~&M~niver-sity~allahasse~FL42807T U.S.A. Abstract. Heteroperreyia hubrichi, a foliage feeding sawfly of Schinus terebinthifolius, was studied to assess its suitabilrty as a classical biological control agent of this invasive weed in Hawai'i. No-choice host-specificity tests were conducted in Hawaiian quarantine on 20 plant species in 10 families. Adult females oviposled on four test species. Females accepted the Hawaiian native Rhi~sandwicensis as an oviposition host equally as well as the target species. The other three species received dramatically fewer eggs. Neonate larvae transferred onb test plants successfully developed to pupae on S. terebinthifolius (70% survival) and R, sandwicensis (1% survival). All other 18 test plant speciesfailed to sumort larval development. A risk assessment was conducted to quantify the suitabilityof non-target plant's'as a host to H. hubrichion the basis of the insects' ~erformance at va;ious stages h its life cycle. Risk to all plant species tested was insignificant except R. sandwicensis. Risk to this native plant relative to S. terebinthifolius was estimated at 1%. Currently this is too high a risk to request introduction of this insect into the Hawaiian environment. Detailed impact studies in the name range of S. rerebinrhrfolius are needed to identfy the potential benefit that this insect offers. Also, field studies in South America with potted R. sandwicensis would give more reliable analysis of this plants risk from natural populations of H. hubrichi. Key Words: Schinus tembinthifolius, Heteroperreyia hubrichi, Rhus sandwicensis, Brazilian peppertree, Christmasberry, classical biological control, host specificity, risk assessment, non-target impacts. INTRODUCTION Schinus terebinthifolius Raddi (Sapindales, Anacardiaceae), locally known as Christmasberry in Hawai'i, or Brazilian peppertree in Florida, is an introduced perennial plant established throughout the Hawaiian Islands (Yoshioka and Markin 1991). This species is native to Argentina, Brazil, and Paraguay (Barkley 1944, 1957) and was brought to Hawai'i as an ornamental before 1900 (Neal 1965). As early as 1928, state foresters began planting this tree in reforestation efforts on state forest reserves throughout four of the main Hawaiian Islands (Skolmen 1979). The plant is a dioecious, evergreen large shrub to small tree that has compound shiny leaves. Flowers of both male and female trees are white and the female plant is a prolific producer of bright red fruits. The green foliage and bright red fruits have been popular in Hawai'i for Christmas wreaths and decorations (Wagner et a/. 1990). A less common Hawaiian name for this plant is "wile-laiki", named for Willie Rice, a politician who often wore a hat lei made of the fruits (Neal 1965). In Hawai'i, S. terebinthifolius has become an aggressive, rapidly spreading weed that displaces native vegetation (Bennett et a/. 1990, Guddihy and Stone 1990). The plant

35 occurs from near sea level to about 920 m (Wagner et al. 1990). As early as the 1940's, S. terebinthifolius was recognized as an important invader of dry slopes on Oahu (Egler 1942). Hawai'i Department of Agriculture recognizes the plant as a noxious weed (Morton 1978). Conservation organizations consider Christmasberry a high priority target in Hawai'i because it is already widespread and has great potential to increase its range even farther (Randall 1993). The U.S. Fish and Wildlife Service (1998) identified S. terebinthifolius as one of the most significant non-indigenous species currently threatening federally listed threatened and endangered native plants throughout the Hawaiian Islands. Naturalization of S. terebinthifolius has occurred In over 20 countries worldwide throughout subtropical (15-30") areas (Ewel et al. 1982). Attributes of the plant that contribute to its invasiveness include a large number of fruits produced per female plant, an effective mechanism of dispersal by birds (Panetta and McKee 1997), tolerance to shade (Ewel 1978), fire (Doren et al. 1991), and droughtmsen and Mi3%Fl-9-8-O),andT apparent allelochemical effect on neighboring plants (Medal eta/. 1999). As a member of the Anacardiaceae, S. te~binthifoliushares its allergen causing properties with other members of the family. While not affecting as many people as some of the more notable members of the Anacardiaceae (poison ivy, poison oak, and poison sumac), the plant sap can cause dermatitis and edema to sensitive people (Morton 1978). Resin in the bark, leaves, and fruit have been toxic to humans, mammals, and birds (Ferriter 1997, Morton 1978). The lumber industry has deemed this plant of little value due to its relatively low quality, its poor form due to the multiple, low stems, and the poisonous, resin byproducts (Morton 1978). The sawdust and smoke are particularly dangerous to sensitized people. No control method is currently available against large, dense populations of S. terebinthifolius. Mechanical removal with heavy equipment or chainsaws can be acceptable along accessible areas, such as ditch banks, utility rights-of-ways, or other disturbed areas (Ferriter 1997). Several herbicides and application methods are available that ald in the control of S. ferebinthifolius (Ewel et al. 1982, Gioeli and Langeland 1997, Laroche and Baker 1994, Woodall 1982). However, these non-biological methods are labor intensive, expensive, and provide only temporary control due to the plant's regenerative capability (Medal et el. 1999). In addition, mechanical and chemical controls are unsuitable over a large scale and in most natural settings because they are detrimental to non-target organisms. The plant is intolerant of heavy shading and has been know to die out under some plants, e.g., Schefflera actinophylla (Endl.) Harms (Apiales, Araliaceae) (C. Smith, personal communication). Classical biological control against Christmasberry was initiated in Hawai'i in the mid- 1900's (Yoshioka and Markin 1991). Surveys were conducted in South America (primarily Brazil) for potential biological control agents (Krauss 1962, 1963). Three insect species native to Brazil were released into Hawai'i: a seed-feeding beetle, Lithmeus (=Bmchus) atmnotatus Pic (Coleoptera, Bruchidae), in 1960 (Davis 1961, Krauss 1963); a leaf-rolling moth, Episimus utilis Zimmerman (Lepidoptera, Olethreutidae), in (Beardsley 1959, Davis 1959, Krauss 1963); and a stem-galling moth, Cwsimorpha infuscata Hodges (Lepidoptera, Gelechiidae), in (Davis and Krauss 1962, Krauss 1963). The first two species became established but were reported to cause only minor damage (Clausen 1978, Yoshioka and Markin 1991). A seed-feeding wasp, Megastigmus tmnsvaalensis (Hussey) (Hymenoptera, Torymidae), accidentally introduced from South Africa, has been found attacking seeds of Chrlstmasberry in Hawai'i since early 1970's (Beardsley 1971, Yoshioka and Markin 1991). Recent classical biological control efforts against S. terebinthifolius have been focused in Florida since the late 1980's. This plant is listed as a Florida noxious weed (FDACS 1994); it is displacing native vegetation in parks and natural areas (Bennett and

36 Habeck, 1991) and is estimated to infest over 4050 kmz (Habeck 1995). Exploratory surveys for natural enemies in Brazil identified at least 200 species of arthropods associated with S. terebinthifolius (Bennett et al. 1990, Bennett and Habeck 1991, Medal et a/. 1999). Based on f~eld observations of thew damage and lack of records that indicate an association with cultivated plants in Brazil, several insects were selected as biological control candidates for further study in Florida. Host specificity studies were conducted on the sawfly Heteroperreyia hubrichi Malaise (Hymenoptera. Pergidae) in Brazil and at a Florida quarantine facility (Medal et a/. 1999). Larval development and female oviposition tests of H. hubrichi were conducted on 36 plant species in 15 families. The insect was determined to be host specific to S. terebinthifolius and a request for release of this insect into the Florida environment is currently under evaluation by Animal and Plant Health Inspection Service, USDA (Medal etal. 1999). Capitalizing on biological studies and host specificity tests conducted in Brazil and Flomara-biological-controIpr0ject wasirritiated to-evaluatethepotentiai-offwhubrichfas a control agent of S. terebinthifolius in Hawai'i (Hight et a/. in press). This paper presents a synopsis of the investigation on the host range of H. hubrichi in Hawaiian quarantine and a risk assessment for non-target plants. MATERIALS AND METHODS Twenty plant species underwent host specificity testing in the Volcano Quarantine Facility. The selected plants belonged to one of three groupings: taxonomically associated plants, habitat associated native plants, and habitat associated agricultural plants (Table 1). Plant relatedness is based on the phylogenetic system of Cronquist (1981). The order Sapindales has 15 families and four of these families (Anacardiaceae, Rutaceae, Sapindaceae, and Zygophyllaceae) have native as well as introduced members in Hawai'i. The single, native, Hawaiian species of Zygophyllaceae, Tribulus cistoides L., was not tested because it occurs only in coastal habitats below 50 m elevation (Wagner et el. 1990). Of the remaining 11 families, only members of the family Meliaceae have been introduced into Hawai'i. Plants that make up the second group are native plants that occur in the same habitat and are therefore likely to be exposed to any introduced biological control agent. The second group is not as closely related to S. terehinthifolius, although members in three families (Araliaceae/Apiales, MyrtaceaelMyrtales, and FabaceaetFabales) are in the same subclass (Rosidae). The third group contains two important, woody, crops that are found associated with S. terebinthifolius habitat. These two species are in the same subclass as S. terebinthifolius. Insect Material. Two shipments of H. hubrichi were imported from Brazil into the Hawai'i Volcanoes National Park Quarantine Facility. The first shipment was received 19 November 1998 and consisted of 236 neonate larvae, which eclosed from four egg masses, and 192 late instar larvae. The second shipment arrived 22 March 1999 and contained 101 late instar larvae. Individuals of both shipments were collected in southern Brazil around the city of Curitiba, Parani! State. Quarantlne host speclflclty tests were conducted from subsequent generations reared in captivity. Both male and female adults can fly, although the male is a stronger flyer. Neither the male or female adult H. hubrichi feed. However, both sexes were observed drinking from small water droplets.

37 Adult Oviposition Tests. No-choice oviposition tests were conducted in the quarantine facility on cut shoots for each of the 20 test plant species. Tests were conducted in plastic containers holding a single stem of a test plant (with 2 to 4 leaves). A mated female H. hubrichi was placed on the test plant and if she oviposited, she remained inside the container with her eggs. If a female did not oviposit on the test plant within 48 to 60 hr, she was removed and placed in a new oviposition arena with a stem of S. terebinthifolius to evaluate her fecundity. Number of eggs laid and viability of eggs were recorded. For all plant species, tests were replicated at least four times. Citnrs sinensis (L.) Osbeck (Sapindales, Rutaceae) was not tested because of lack of plant material. Tests on this plant in Florida and Brazil found this to be an unacceptable host plant. Oviposition tests were conducted on potted plants of five test species on which oviposition has occurred andlor on whlch larvae had developed on cut shoots. A mated female was placed on the caged test plant until she died. The number of eggs laid and viability of eggs was recorded. Each plant species was replicated at least six times. No-Choice Larval Development Tests. All test plants were evaluated as to their ability to support larval development under nochoice conditions. Unfed, neonate larvae less than two hours old were transferred to small cut shoots of the test plant stuck into moistened florist-foam-filled vials and reared in 480 ml plastic containers. Since larvae feed gregariously, 15 larvae were transferred into each container with a fine tip brush. Each test plant was replicated at least six times. For each family of larvae used in the tests, 2-3 replicates of larvae were reared on S. terebinthifolius to insure the vitality of each egg mass. Containers were cleaned, larvae were fed, and mortality was assessed on the third day after transfer and then every fourth day. Containers were evaluated every day after larvae became sixth instars. Larval development tests were also conducted on potted plants of five test species because of oviposition activity andlor larval development on cut shoots. Each plant had an egg mass of H. hubricni either naturally oviposlted on the stem or tied onto a stem from a successful oviposition on S. terebinthifolius. The number of larvae that successfully developed on each test plant was recorded. The test was replicated on each plant species at least three times. Relative Host Suitability In an attempt to quantify potential suitability of non-target plant species for agent development, Wan and Harris (1997) developed a scoring system that compares the suitability of non-target species to that of the target species. I have followed their approach to obtain estimate host suitability. The index of suitability of a non-target host plant for H. hubrichi use is R1 r R2 x... R,,, where R is the performance of the insect at various life stages on the test plant relative to that on S. terebinthifolius. Suitability parameters estimated for each test plant species included the proportion of females that oviposited on the plant, number of eggs oviposited, proportion of larvae that survived, and development time of larvae fram eggs to pupae (Table 2). For purposes of calculation, zero values for any parameter (complete rejection or failure) were taken to be RESULTS Insect Biology. The adults of H. hubrichi are generally black with yellow legs. A female and male H. hubrichi mate on the surface of soil or plants, although females do not need to mate for oviposition to occur. Each female oviposits her eggs in a single mass just into the surface of non-woody stems. Eggs in a mass are arranged in rows and the female

38 "guards" her eggs until she dies, just before the eggs hatch. Eggs hatch in 14 days. Neonate larvae feed gregariously on both surfaces of young leaflets at the tip of shoots. As they grow they move as a group onto new leaflets and larger leaves until the third to fourth instar when they disperse throughout the plant and feed individually. A larva is green with red spots and black legs. After reaching the seventh instar, the larva moves into soil and pupates. Insects reared on S. terebinthifolius took days from egg natcn to pupation. Pupation lasted two months for 80% of pupae and the longest successful pupation occurred in seven months. Adult Oviposition Tests. Female H. hubrichi oviposited on cut shoots of five different test plant species (Table 1). All females that were placed on S. terebinthifolius and R, sandwicensis oviposited on their test plant. Less than half of the females placed on the other four test species s uccess~lly~osi t E t successfully oviposited once they were moved onto S. terebinthifolius after the hr test period. This indicated that the females were capable of ovipositing on the test plant but rejected that plant species as an oviposition host. Mean number of eggs oviposited by females on each test plant species is presented in Table 1. There was no significant difference in the number of eggs deposited on R. sandwicensis and on S. terebinthifolius (t-test; p> 0.05; t(43) = 1.762). Oviposition on the h~ir-te~t-ptdnt-~ta1,1e-2)~0~e'~~r~ali-n~n=0vip~0~itin~emale~~ three Sapindaceae test plant species was highly variable with most tests receivii;~ ;~c, eggs. In those plants receiving eggs, the average number deposited was high: Dodonaea viscosa - 57 eggs; Litchi chinensis - 78 eggs; and Euphoria longan - 56 eggs. Oviposition was more restricted on potted plants than on cut shoots. Mated H, hubrichi females oviposited on only three of the five species of potted test plants (S. terebinthifolius, R, sandwicensis, and E. longan). Females did not oviposit on potted D. viscosa or L. chinensis, even though oviposition did occur on cut shoots of D. viscosa and L. chinensis. No-Choice Larval Transfer Tests. Neonate larvae successfully developed on cut shoots of only two test plant species, S. terebinthifolius and R. sandwicensis. Larvae on most of the other test plant species were deac! within seven days (Table 1). Although cut shoots of two additional plant species supported some larval development for more than two weeks, (Mangifera indica (Sapindales, Anacardiaceae), 23 d and E, longan (order, family) 19 d), no larvae survived to pupation. Successful larval development on the five potted plant species was similar to development on cut shoots. Larvae developed only on potted S. te~binthifolius and R. sandwicensis. The proportion of larvae successfully developing on S. terebinthifolius and R. sandwicensis potted plants was slightly higher to the proportion on cut shoots of those two test plant species (78% and 4Oh, respectively). Relative Host Suitability The relative host suitability of the test plant species is shown in Table 3. Suitability estimates are calculated only for the five plant species that received eggs from ovipositing females. Scores for all four non-target plants were lower than for S. terebinthifolius, measured at 1.O. All other 15 tested species were unacceptable host for both oviposition and larval development and are not at risk by the release of H. hubrichi into Hawai'i.

39 DISCUSSION Field observations in Brazil and laboratory feeding tests in Florida indicated that H. hubrichi was highly host specific and safe to release into the Florida environment (Medal et a/. 1999). Additional host specificity studies in quarantine primarily on native Hawaiian plants confirmed a highly limited host range for H. hubrichi Tests at all locations showed that S. terebinthifolius was the preferred, if not the only host plant of H. hubrichi. However, the potential host range in Hawai'i appears to be slightly broader than that ~dent~f~ed in Florida and Brazil. Tests in Florida evaluated two North American species of sumac (R. copallina and R. michauxio and found them unsuitable for H. hubrichi oviposition and incapable of supporting larval development (Medal et.al 1999, J. Cuda, personal communication). Hawaiian tests indicated that the Hawaiian sumac (R. sandwicensis) dld support larval development and was hlgllly attfactlve to the female for _ oviposition. Chemicals still present in ancestral, continental species that deter herbivorous insects may have been lost over time in the Hawaiian sumac. Of the five varieties of S. terebinthifolius recognized in South America (Barkley 1944), H. hubrichi prefers the most pubescent variety (M. Vitorino, personal communication). The dense pubescent nature of R. sandwicensis may stimulate female oviposition regardless of the quality of the plant for larval development. Both S. terebinthifolius and R. sandwicensis were comparable in their acceptance by ovipositing females as measured by proportion of females that oviposited on the test plant and the number of eggs that a female laid. But R. sandwicensis was a dramatically poor host for H hubrichi larvae in both performance characteristics of larval survival and development time. To identify the potential non-target effect that native R. sandwicensis might be exposed to because of the introduction and release of H. hubrichi into Hawai'i a host suitability assessment was conducted. To arrive at realistic estimates of host suitability, both physiological and behavioral processes must be estimated (McEvoy 1996). Estimates of host suitability were determined by quantifying crucial stages in the sawflies sequence to locate, accept, and develop on the host, i.e., oviposition by the female, larval development time, and larvae survival rate from egg to pupa in no-choice tests. Relative host suitability of non-target species was evaluated for the five test plant specres that exper~enced any establishment andlor damage from H. hubrlchi in the host specificity tests. Four plant species had extremely low levels of suitability (Table 3). In fact, since all four of these plants completely failed to support larval development it may be argued that their suitability for H. hubrichi development is zero. The life cycle of H. hubrichi would be interrupted if the insects were to colonize any one of these plants and a population of H. hubrichi would fail to establish. A low suitability level was measured for R. sandwicensis (approximately 1%). Introduction of H. hubrichi into Hawai'i will not be requested at this time because of the apparent risk to R. sandwicensis. However, additional information is being sought which may reverse this decision. Field experiments in Brazil with potted R. sandwicensis are being proposed to evaluate the risk of this non-target plant under more natural settings. The observed host range of herbivorous insects is often wider under laboratorybased tests than open-field tests (Cullen Briese 1999). In addition. the risk inherent in introducing a biological control agent may be outweighed by its benefit. Therefore, detailed impact studies are needed in Brazil to evaluate the effect H. hubrichi has on S. terebinthifolius fitness. Neither of these types of tests is currently funded. Additional surveys for phytophagous insects of S. terebinthifolius should be conducted in northern Argentina, the most likely center of origin of this species (Barkley 1944). Virtually all previous South American explorations by scientists from Hawai'i (Krauss 1962, 1963) and Florida (Bennett et a/. 1990, Bennett and Habeck 1991) have

40 taken place in southern Brazil. Although this work has identified several promising biological control candidates, additional surveys may be more successful in Argentina. For example, on a 10-day survey in January 2000 of S. terebinthifolius natural enemies in the state of Missiones, Argentina, two specles of stem boring Cerernbicidae and a bark girdling Buprestidae were collected (S. Hight, unpublished data). Identifications of these insect species are pending. No stem boring or bark girdling insects were identified from Brazilian surveys. ACKNOWLEDGMENTS I thank Clifford Smith and Julie Denslow for comments on earlier drafts of this manuscript. I am grateful to Jonathan Chase, Donovan Goo, Baron Horiuchi, Brian Kiyabu, Patti Moriatsu. Roddy Nagata, Wendell Sato, and Alan Urakami for collecting, propagating, and/efdon&ingtestpia~tsuse&in-this-r~.ma~~lo-vitorinoanddhendque---- Pedrosa-Macedo are acknowledged for their assistance in collecting H. hubrichi in Brazil. The National Park Service is acknowledged for their support and use of the Hawaii Volcanoes National Park Quarantine Facility. A special thanks to Ivan Horiuchi for technical assistance throughout this study and to Clifford Smith for his sustained help and guidance. LITERATURE CITED Barkley, F. A Schinus L. Brittonia 5: Barkley, F. A A study of Schinus L. Lilloa Revista do Botanica. Tomo 28. Universidad Nacional del Tucumen, Argentina. Beardsley, J. W Episimus sp. Pmceedings, Hawaiian Entomological Society 17: 28. Beardsley, J. W Megastigmus sp. Proceedings, Hawaiian Entomological Society 21: 28. Bennett, F. D., L. Crestana, D. H. Habeck, and E. Berti-Filho Brazilian peppertree - prospects for biological control. pp , In: Proceedings of the VII International Symposium on Biological Control of Weeds, March 1988, Rome, Italy. E.S. Delfosse (ed), lstituto Sperimentale per la Patologia Vegetale (MAF), Rome, Italy. Bennett, F. D. and D. H. Habeck Brazilian peppertree - prospects for biological control in Florida. pp , In: Proceedings of the Symposium of Exotic Pest Plants, 2-4 November 1988, Miami, FL. T. D. Center, R. F. Dorcn, R. L. Hofstetter, R. L. Myers, and L. D. Whiteaker (eds), U.S. Department Interior, National Park Service, Washington, DC. Briese, D. T Open field host-specificity tests: Is "natural" good enough for risk assessment? pp ! In: Host Specificity Testing in Australasia: Towards Impmved Assays for Biological Control. T. M. Withers, L. Barton-Browne, and J. Stanley (eds), CRC for Tropical Pest Management, Brisbane, Australia.

41 Clausen, C. P. (ed) Introduced Parasites and Predators of Arthropod Pests and Weeds: A World View. Agriculture Handbook 480. Agricultural Research Service, USDA, Washington, DC. Cronquist, A An Integrated System of Classification of Flowering Plants. Columbia University Press. New York. Cuddihy, L. D. and C. P. Stone Alteration of Native Hawaiian Vegetation: Effects on Humans, Their Activities and Introductions. University of Hawai'i Press, Honolulu, HI. Cullen, J. W Current problems in host-specificity screening. pp , In: Proceedings of the VII lntemational Symposium on the Biological Control of Weeds, March E. Delfosse (ed), lstituto Sperimentale per la Patologia Vegetale, Rome, Italy. Davis, C. J Recent introductions for biological control in Hawaii - IV. Proceedings, Hawaiian Entomological Society 17: Davis, C. J Recent introductions for biological control in Hawaii - VI. Proceedings, Hawaiian Entomological Society 17: Davis, C. J. and N. L. H. Krauss Recent introductions for biological control in Hawaii - VI I. Proceedings, Hawaiian Entomological Society 1 8: Doren, R. F., L. D. Whiteaker, and A. M. LaRosa Evaluation of fire as a management tool for controlling Schinus terebinthifolius as secondary successional growth on abandoned agricultural land. Environmental Management 15: Egler, F. E Indigene versus alien in the development of arid Hawaiian vegetation. ECO~O~Y 23: Ewel, J. J Ecology of Schinus. pp. 7-21, In: Schinus: Technical Proceedings of Techniques for Control of Schinus in South Florida: A Workshop for Natural Area Managers, December 2, The Sanibel Captiva Conservation Foundation, Inc., Sanibel, FL. Ewel, J. J., D. S. Ojirna, K. A. Karl, and W. F. DeBusk Schinus in Successional Ecosystems of Everglades National Park. South Florida Research Center Report T USDI, National Park Service, Washington, DC. FDACS - Florida Department of Agriculture and Consumer Services Biological Control Agents: Introduction or Release of Plant Pests, Noxious Weeds, Arthropods, and Biological Control Agents. FDACS, Gainesville, FL Ferriter, A. (ed), Brazilian Pepper Management Plan for Florida: Recammendafions from the Brazilian Pepper Task Force, Florida Exotic Pest Plant Council. The Florida Exotic Pest Plant Council, Florida. Gioeli, K. and K. Langeland Brazilian Pepper-tree Control, SS-AGR-17 University of Florida, Cooperative Extension Service, Gainesville, FL.

42 Habeck, D. H Biological control of Brazilian peppertree. Florida Nature 68: Hight, S. D., I. Horiuchi, M.D. Vitorino, C.Wikler, and J.H. Pedrosa-Macedo Biology, host specificity, and risk assessment of the sawfly Heteropemyia hubrichi, a potential biological control agent of Schinus terebinthifolius in Hawaii. Biological Control. Accepted. Krauss, N.L.H Biological control investigations on insect, snail and weed pests in tropical America, Pmceedings, Hawaiien Entomological Society 18: Krauss, N. L. H Biological control investigations on Christmas berry (Schinus tembinthifolius) and emex (Emex spp.). Pmceedings, Hawaiian Entomological SocletyT8:r Laroche, F. B. and G. E. Baker Evaluation of several herbicides and application techniques for the control of Brazilian pepper. Aquatics 16: McEvoy, P. B Host specificity and biological pest control. BioScience 46: Medal, J. C., M. D. Vitorino, D. H. Habeck, J. L. Gillmore, J. H. Pedrosa, and L. D. De Sousa Host specificity of Heteropemyia hubrichi Malaise (Hymenoptera: Pergidae), a potential biological control agent of Brazilian Peppertree (Schinus te~binthifolius Raddi). Biological Control 14: Morton, J. F Brazilian pepper - its impact on.people, animals and the environment. Economic Botany 32: Neal, M. C In Gardens of Hawaii. B.P. Bishop Museum Special Publication 50. Bishop Museum Press, Honolulu, HI. Nilsen, E. T. and W. H. Muller A comparison of the relative naturalization ability of two Schinus species in southern California. I. Seed germination. Bulletin Torrey Botanical Club 107: Panetta, F. D. and J. McKee Recruitment of the invasive ornamental, Schinus tembinthifolius, is dependent upon frugivores. Australian Journal Ecology 22: Randall, J. M Exotic weeds in North American and Hawaiian natural areas: The Nature Conservancy's plan of attack. pp , In: Biological Pollution: The Contml and Impact of lnvasive Exotic Species. B.N. McKnight (ed). Indiana Acad. Sciences, Indianapolis, IN. Skolmen, R. G Plantings on the Fomst Reserves of Hawaii, U.S. Forest Service, Institute of Pacific Islands Forestry, Honolulu, HI. U.S. Fish and Wildlife Service Draft Recovery Plan for Multi-Island Plants. U.S. Fish and Wildlife Service, Portland, OR.

43 Wagner, W. L., D. R. Herbst, and S. H. Sohmer Manual of the Flowering Plants of Hawai'i. University of Hawai'i Press, Honolulu, HI. Wan, F. and P. Harris Use of risk analysis for screening weed biocontrol agents: Altica carduorum Guer. (Coleoptera: Chrysomelidae) from China as a biocontrol agent of Cirsium antense (L.) Scop. in North America. Biocontrol Science and Technology 7: Woodall, S. L Herbicide Tests for Control of Brazilian-pepper and Melaleuca in Florida. USDA Forest Service Research Note SE 314. Southeastern Forest Experiment Station, Asheville, NC. Yo s hiaka,-e-r.-anclggp_marki n _199~1_I:ff~d~~o_fbi~I_0g~alcantolofChristmasber~~~~ (Schinus terebinthifolius) in Hawaii. pp , In: Proceedings of the Symposium of Exotic Pest Plants, 2-4 November 1988, Miami, FL. T. D. Center, R. F. Doren, R. L. Hofstetter, R. L. Myers, and L. D. Whiteaker (eds), U.S. Department Interior, National Park Service, Washington, DC.

44

45

46 Convolvulaceae lpomoea indica* 6 6 : Dicksoniaceae C. Habitat Associated Agricultural Plants Proteaceae Rubiaceae Cibotium glaucum* Macadamia integnrolia Coma arabica : 90 6 : 90 6 : 90 Y = Species native to Hawai'i Number of individuals tested for oviposition is same as number of oviposition tests, but n mber of individu development varied with test indicates normal larval feeding; + + indicates moderate larval feeding; + indicates sl'ght larval feedin occasional nibbling by larvae; and - indicates that no larval feeding occurred I l

47

48 Table 3. Relative host suitability analysis for Heteropeneyia hubrichi performance on various host plant test species in Hawaiian quarantine. Performance ~easure' Plant Species Relative Suitability S. ferebinthifolius OOO 1.OOO R sandwicensis I D. viscosa x la9 L. chinensis x E. longan x lo-' ' Performance measure estimates are relative to S. terebinthifolius. 1 = proportion of females that oviposit; 2 = mean number of eggs oviposited; 3 = mean development time of larvae; 4 = proponion of eggs that survive to pupae.

49 BIOLOGICAL CONTROL POTENTIAL OF MICONIA CALVESCENS USING THREE FUNGAL PATHOGENS Eloise M. Killgore Biological Control Section, Hawai'i Department of Agriculture, P. 0. Box 22159, Honolulu, Hawai'i , U.S.A. Em ail: corn Abstract. Biological control of miconia (Mimnia calvescens) became a management option as soon as the severity of its threat to Hawaiian ecosystems was recognized. No weed in Hawai'i has received as much publicity, attention, and funding for control. Three fungal pathogens have been considered as potential agents. Colletotrichum gloesoporioides f. sp. miconiae was assessed within six months, the petition for release approved within eight months and the fungus released on the islands of Hawai'i and Maui in It is established on Hawai'i and has spread to other areas. Its effectiveness is under evaluatlon. Pseudocercospora tamonae causes extensive damage to leaves, attacks other melastomes and the seedlings of some Myrtaceae but only fruits on miconia. It is very uncertain whether this species will be approved for release. Coccodiella myconae produces large wart-like growths that deform leaves considerably. It appears to be an obligate parasite of miconia but hyperparasitized by another species tentatively identified as Sagenomella alba. It has proven difficult to transfer from one plant to another where it does not sporulate. Further work on this species is in progress. Key words: Biological control of weeds, Coccodiella myconae, Colletotrichum gloeosporioides f. sp. miconiae, invasive species, Melastomataceae, Miconia calvescens, Pseudocercospora tamonae, Sagenomella alba. THE TARGET WEED, MICONIA CALVESCENS Early Considerations Davis (1978) first expressed concern about the threat of Miconia calvescens DC (Myrtales, Melastomataceae) in Hawai'i. In January 1991, a miconia tree with seedlings was discovered in a plant nursery near Hana, Maui. By midyear, surveys revealed additional populations in the surrounding area including mature flowering trees (Gagne et a/. 1992). The threat from this plant generated considerable publicity (Altonn 1991, Eager 1995, Tanji 1996a,b, Yohay & Fukutomi 1997). The resilience, dominance of emergent~1;conia~ants~7atio~~pi~stm~their-fecndtty;-widesprea~ dissemination by frugivorous birds, the erosion associated with the shallow-rooted miconia trees and its deleterious impact on native forests of Tahiti and Moorea were described by Meyer (Meyer 1994,1996). Medeiros eta1 (1997) noted that the similarity in stature, composition, and requirements of climate of Hawaiian and Tahitian forests strongly suggested similar vulnerab~l~ty. The publicity stimulated many private and public agencies to support control activities Melastome Action Committees The miconia problem generated considerable support but it lacked leadership. Maui Land and Pineapple Company had similar concerns with another weed Tibouchina hehacea (DC) Cogn. (Myrtales, Melastomataceae). The combined interest led to the organization of the Melastome Action Committee (MAC) committee by Tri-Isle Resource Conservation and Development Office, U.S. Department of Agriculture (Medeiros

50 1998). Many private and government agencies participated: Biological Resources Division U.S. Geological Survey; U.S. Fish and Wildlife Service; U.S.D.A. Forest Service; National Park Service; Hawai'i Army National Guard; Hawai'i Department of Agriculture (HDOA); Hawai'i Department of Land and Natural Resources; University of Hawai'i; Maui County's Office of Economic Development; and, The Nature Conservancy (Conant 1996). This proactive committee furthered public awareness and planned a broad control strategy against miconia principally on the island of Maui. MAC focused primarily on the containment of miconia using chemical and mechanical eradication because the bulk of the funds were dedicated for local use only. Other funding was obtained for initial exploratory work on biological control. A somewhat similar committee was established later on Hawai'i with funding again focused on local control efforts. Different control strategies were taken because the principal infestations on Hawai'i were on small parcels of private property whereas those on Maui were on large areas of primarily state lands. Within a few years MAC became the Maui lnvasive Species Committee. The Hawai'i committee was later integrated with the Big Island lnvasive Species Committee. The focus on the management of melastomes diminished in light of other problems resulting in a much less focused effort against miconia. Funds for biological control were decreased significantly and would have ceased but for the persistence of one or two people. Their efforts have established new funding for renewed exploratory and biological studies for potential invertebrate agents in Costa Rica and Brazil. BIOLOGICAL CONTROL The search for natural enemies of miconia initially was the responsibility of HDOA. Their staff included an experienced exploratory entomologist and many biological control researchers as well as limited insect and pathogen quarantine facilities. Exploration The initial exploratory studies between July 1993 and September 1995 were conducted in Costa Rica, Brazil, Paraguay, and Trinidad and Tobago. Many insect feeders and several diseases were collected and sent into quarantine in Hawai'i (Burkhart 1996). Burkhart recommended that biological control studies focus on the pathogens because, apart from some processionary caterpillars (Lepidoptera, Riodinidae), the insects did -not~e~ave~pact-o~-the~~~-werepr~bab~-~okhost~spe~ific In 1996, Barreto began exploration for diseases of miconia in Brazil. He shipped many fungi that were isolated from miconia plants into quarantine in Hawai'i. He also traveled to the Dominican Republic and Costa Rica to relocate three of the fungi mentioned by Burkhart. He later collected the same fungi in Brazil and recommended all three pathogens for further screening. Further exploration was conducted in 1996 and 1998 in Guatemala where plants closer to the Hawaiian biotype were thought to exist (Killgore 1996, Ramadan 1998). Very sparse populations of miconia were found throughout the country. Failure to establish collaboration with Guatemalan scientists dimmed prospects for further research on several prospective biological control insects, particularly a Margardisa sp. (Coleoptera, Chrysomelidae), found in the Peten and Coban areas of the country. No new pathogens were found.

51 Barreto (2000) explored several regions of Ecuador for diseases of miconia but found nothing new. With little hope for new diseases the search for other collaborators to reconsider insects in Central America resulted in the establishment of a cooperative agreement with the University of Costa Rica. A psyllid has already been recommended and interest in at least one species in the Riodinidae rekindled. Host Range Testing The widely accepted protocol for selecting host range test plants follows the centrifugal phylogenetic method first proposed by Wapshere (1974). Members of the family Melastomataceae were challenged first, followed by species in other families within the Order Myrtales. All members of the Melastomataceae in Hawai'i are naturalized alien species IAhrrecla-t990).ostarewedy andnoxious;andinchd-idernia-hirt*l+d;80~-- Tibouchina herbacea (DC) Cogn., T. longifolia (Vahl) Baill. ex Cogn., T. uwilleana (DC) Cogn., Adhrostema ciljafum Pav. ex D. Don, Oxsypora paniculata (D. Don) DC, Medinilla venosa (Blume) Blume, Dissotis rotundifolia (Sm.) Trian, Heterocentron subtriplinen~ium (Link & Otto) A. Braun & C. Muell., Melastoma candidum D. Don, M. sanguineum Sims, Pterolepis glomerata (Tottb.) Miq. Tetrazygia bicolor (Mill.) Cog n., and Trembleya phlogiformis DC. Because none of these plants is endemic, indigenous, or economically important in Hawai'i except as ornamentals, a pathogen of M. calvescens capable of infecting these melastomes could still remain a candidate for biological control. A pathogen, that did not infect any other melastome, was not expected to infect any plant species outside of the family and was deemed highly specific and desirable for biological control purposes. The need for careful, thorough screening (Watson 1985) was confirmed by results with Pseudocercospofa tamonae (see below). Other than the family Melastomataceae, there are only 19 genera within the Order Myrtales that occur in Hawai'i (Wagner et a/. 1990). Some are endemic, indigenous or have economic importance including Terminalia L. (Combretaceae), Cuphea P. Br. (Lythraceae), Lythrum L. (Lythraceae), Eucalyptus L' Her. (M yrtaceae), Eugenia L. (Myrtaceae), Metrosideros Banks ex Gaertn. (Myrtaceae), Psidium L. (Myrtaceae). Syzygium Gaertn. (Myrtaceae), and Wikstroemia Endl. (Thymelaceae). Susceptibility of any of the plant species belonging to these genera would necessitate further evaluation. Host range tests are typically performed under the most advantageous conditions for the pathogen. For fungi, these conditions would normally include a very high concentration of spores of 1 x lo5 per ml or higher, and a relative humidity of 100% for 16 to 48 hours. Host range testing under these conditions often indicates a broader host range than is found under field conditions (Watson 1991), and may distort the evaluation of maximum risk posed by a biological control candidate resulting in the rejection of agents that are really safe and useful. The pathogens Colletotrichum qloeos~orioides (Penz.) Sacc. f. sp. miconiae (Phvllachorales, Phllachoraceae).-This fungus causes leaf spots on miconia resulting in leaf yellowing and premature defoliation. It reproduces by asexual spores, or conidia, produced in acervuli that arise on the abaxial leaf surface. Setae are sometimes observed in these structures. The conidia are pm long and pm wide, straight, cylindrical, with rounded ends. Conidia of Colletotrichum fungi are produced under high humidity conditions and are disseminated by "wind-driven rain" (Trujillo, pers. com.). All

52 test plants were inoculated using a spore concentration of 1 x 1 o5 conidialml in sterile water and incubated for 48 hours in an enclosed chamber at 100% relative humidity. Host range testing, concluded in November 1996, showed that this fungus was restricted in pathogenicity at least to the genus Miconia. The most closely related species, Clidemia hirta, was not susceptible. This form of the fungus did not infect any other species in the Melastomataceae, which occur in Hawai'i, or any member of the other families in the order Myrtales. Based on the host specificity tests, the fungus was subsequently described as f.sp. miconiae of Colletotrichum gloeosponoides (Killgore et al. 1999). The request to release C. g, miconiae from the containment facility was submitted in December 1996 to HDOA for state approval, which was granted on March 3, 1997, and forwarded to USDA APHIS PPQ. The Federal permit was signed on July 11,1997 (Killgoreeta1,1998),~nd-thefungusl.eleasebontUand~fWawili~h~rtlyf heteafter~ and on Maui later that year. Attempts to establish the disease on Maui have failed so far. The fungus requires rain and wind for spore dissemination and recent drought conditions may have limited its spread. Studies on the impact of the fungus are ongoing. Under aseptic laboratory conditions the fungal pathogen attacked germinating miconia seeds and also kills newly emergent seedlings (Su Que Leong, pers. corn.). If these observations are confirmed in the field they suggest that C. g. miconiae could play an even more important role as a biological control agent for M. calvescens. Pseudocercos~ora tamonae (Chupp) Braun (Deuteromvcotina, Dernatiaceae1.-This fungus was isolated and identified by Barreto from leaves of Miconia phanerostila Auth. (Myrtales, Melastomataceae) and also from M. calvescens from Rio de Janeiro, Brazil. The minute leaf spots did not appear to be damaging, but when pathogenicity tests on miconia were completed, the pathogen proved to be more aggressive than C. g. miconiae. Besides causing numerous leaf spots, infected leaves became deformed and defoliation occurred three weeks after inoculation. The conidia are pale brown, cylindrical, tapering towards the apices, x 3-5 pm with septa. They are produced on conidiophores, which emerge from diseased leaf tissue. High humidity favors spore production and spores are easily disseminated by air currents. Unlike the C. g. miconiae, however, Pseudocercospora tamonae was not as host specific. It infected other species within the Melastomataceae including Clidemia hirta, Arfhtustema ciliata, Dissotis rotundifolia, Tibouchina urvilleana and T. herbacea. It also infected members of the Myrtaceae, including Metrosideros polymorpha Gaud., Psidium cattleianum Sabine and Syzygium malaccense (L.) Merr. & Perry. More leaf spots developed on M. calvescens leaves than on any other susceptible plant species, and sporulation of P. tamonae was only observed on miconia. Leaf yellowing and premature defoliation occurred only on those susceptible genera of the Melastomataceae. Only immature leaves of M. polymorpha, P. cattleianum and S. malaccense became infected, and there was no defoliation. The request to release this pathogen has been submitted. It is expected that the wider host range suggested by the host range test conducted for this fungus will be accepted as representing an aberration due to unnatural experimental conditions. Infections are obtained in the test only when leaves are exposed under very high humidity. The pathology is not ecologically significant as the fungus was unable to complete its life cycle from spore to spore on the non-target plants.

53 Coccodiella myconae (Dubv) Hino & Katuamoto (Phvllacorales, Phvllacoraceae).- Coccodiella myconae was collected in Costa Rica and Brazil Barreto, who noted that it should be transferred to Coccodiella. It is extremely common in Brazil but always associated with the hyperparasite provisionally identified as Sagenomella alba W. Gams & Soederstrom (Eurotiales, Trichocomaceae). Infection produces wart like growths on the adaxial leaf surface with a corresponding concavity on the abaxial side resulting in the infected leaf becoming deformed and falling prematurely. Dark brown to black stromata line the concavities in a somewhat circular pattern. Perithecia develop within the stromata and produce asci ( x 6-9 pm) with unicelluar ascospores (6-9 pm). Diseased samples were sent on numerous occasions to the HDOA pathogen -qt;la~antine-fasilit~n-monddu-b~t-thefunguscould-n~h~ultuce~c~sposes~~~ collected from diseased leaves were inoculated onto Hawaiian miconia plants, but the transfer was successful in only three of seven attempts. In each case, however, the fungus failed to develop mature fruiting structures and the fungus was never recovered. C. myconae is almost certainly an obligate parasite and since most obligates are host-specific, the outlook for this fungus as a biological control agent is extremely favorable. Research into the susceptibility of the Hawaiian miconia biotype, the conditions for infection and disease development, and the life cycle of the fungus are underway in Brazil. DISCUSSION Concurrent research on the biological control of a weed at the same time as conventional control measures are being developed is unusual. The history of this species in Tahiti and its behavior in Hawai'i clearly illustrated its threat to Hawaiian forests (Gagne et al. 1992). Conventional control technologies were viewed as a containment strategy awaiting the development of biological control agents. Funding for each approach had to be sought from different agencies because of differing jurisdictions and constraints. Some weed control specialists believed that miconia had become too well established in Hawai'i and the eradication projects would require too many years of dedicated funding and leadership (Conant, pers. com.). Others felt that miconia could be eradicated in Hawai'i in part from a general opposition to biological control but also from a lack of appreciation of the difficulty of eradicating a species using conventional technologies. The lack of consensus delayed an aggressive approach to biological control. Although C. g. miconiae can slow the growth of established miconia plants, and also cause dieback of young seedlings, it alone will not control this weed. Preliminary observations of field-release plots have shown that the pathogen may decrease population densities. The lack of host specificity in tests with the miconia pathogen, Pseudocercospora tamonae, may be cause for its exclusion as a biological control agent. However, under laboratory conditions, this fungus is a more devastating pathogen than C. g. miconiae and it is not dependent on wind-driven rain for dissemination. Observations of disease development on all susceptible test plants showed that P. tamonae was a primary pathogen of miconia and other melastomes but not other families in the Myrtales where it causes minor disease symptoms. Since one of these hosts is Metrosideros polymorpha, an endemic dominant of most montane forests In Hawai'i, support for

54 releasing P. tamonae will be difficult to obtain. The validity of the concern should be evaluated, Infection only occurred under conditions of maximum humidity and very high spore densities over several hours' exposure, an improbable situation in the field. However, if infection occurred under normal field conditions then the pathogen might, through time, adapt to Metrosideros. Research on the miconia pathogen Coccodiella myconae has not progressed due to difficulties in disease transmission. The potential of this fungus, however, precludes abandonment of this agent at this stage. Ongoing research into the life cycle and mechanism of infection of this fungus may lead to solutions to the transmission problems. Isolation of the fungus from its hyperparasite can be achieved. Total eradication of miconia is and always will be the primary goal of environmentalists in Hawai'i (Conant et a/. 1996). Biological control is basically a con trok-nodeand-vvili-nd-byitdf~rdicatemi~ia--a-t-best,it-wili-resluce-tb~g~ovvthand spread of this weed to the extent that the conventional control means will be successful in critical areas. Meanwhile the search for additional biological control agents continues. ACKNOWLEDGEMENTS Thanks to Dr. C. W. Smith for continuous encouragement on biological control as the only viable long-term solution to miconia. The financial support of the following agencies is acknowledged: Government of French Polynesia, U.S. Geological Service Biological Resources Division, State of Hawai'i, Maui Water Board. Logistical support and other cooperation from the following has assisted the program enormously: U.S. Forest Service, National Park Service, U.S. Geological Service Biological Resources Division, Hawai'i Department of Agriculture, The Nature Conservancy Hawai'i. LITERATURE CITED Almeda, R., Melastomataceae. pp , In: Manual of Flowering Plants of Hawai'i. W. L. Wagner, D. R. Herbst, and S. H. Sohmer (eds.). University of Hawai'i Press and Bishop Museum Press, Honolulu. Altonn, H., Isle forest periled by evil weed's explosive growth. Honolulu Star Bulletin. May 31 : A-8. Barreto, R. W Fungal Pathogens and Natural Enemies of Miconia calvescens and Tibouchina herbacea: Report of a survey made in the Dominican Republic and Cost Rica during December 1998 and January File report, Pacific Cooperative Studies Unit, University of Hawai'i, Honolulu. 7 pp. Barreto, R. W Fungal Pathogens, Natural Enemies of Miconia calvescens: Report of a survey made in Ecuador during May File report, Pacific Cooperative Studies Unit, University of Hawai'i, Honolulu. 10 pp. Burkhart, R The Search For Biological Control Of Miconia calvescens: Photographic Documentation of Natural Enemies of Miconia calvescens (Melastomataceae) found in Central and South America between July 1993 and

55 September smithlmc control.htm Conant, P., A. C. Medeiros and L. L. Loope, A multiagency containment program for miconia (Miconia calvescens), an invasive tree in Hawaiian rain forests. pp , In: Assessment and Management of Plant Invasions. J.O. Luken and J.W. Thieret (eds). Springer Verlag. New York. Davis, J Miconia calvescens. Newsletter, Hawaiian Botanical Society 17: 63 Eager, H., Council members hear detail of miconia threat. The Maui News. March 31 : A-3. Gagne B., L. L. Loope, A. C. Medeiros and S. J. Anderson, Miconia calvescens: a threat to native forests of the Hawaiian Islands. Pacific Science 46: Gardner, D. E., Role of biological control as a management tool in national parks and other natural area. Technical Report NPSINRUHINRTR United States Department of the Interior. Washington, D.C. 41 pp. Killgore, E. M Trip report, HDOA files. Killgore, E. M., L. S. Sugiyama, and R. W. Barreto, Prospective biological control of Miconia calvescens in Hawaii with a non-indigenous fungus Colletotrichum gloeosporioides (Penz.) Sacc. f. sp. miconiae. pp , In: Proceedings of the First Regional Conference on Miconia control, August 26-29, 1 997, Papeete, Tahiti, French Polynesia. J.-Y. Meyer and C. W. Smith (eds), Gouvernement de Polynesie franpiseiuniversity of Hawai'i at ManoaJCentre ORSTOM de Tahiti. Killgore, E. M., L. S. Sugiyama, R. W. Barreto, and D. E. Gardner, Evaluation of Colletotrichum gloeosporioides for biological control of Miconia calvescens in Hawai'i. Plant Disease 83: 964. Klingman, D. L. and J. R. Coulson, Guidelines for introducing foreign organisms into the U.S. for biological control of weeds. Plant Disease 66: Medeiros, A. C., L. L. Loope, P. Conant and S. McElvaney, Status, ecology, and management of the invasive plant Miconia calvescens DC (Melastomataceae) in the Hawaiian Islands. Bishop Museum Occasional Papers No. 48. Medeiros, A. C., L. L. Loope, and R. W. Hobdy, Interagency efforts to combat Miconia calvescens on the Island of Maui, Hawai'i. pp , In: Proceedings of the First Regional Conference on Miconia control, August 26-29, 1997, Papeete, Tahiti, French Polynesia. J.-Y. Meyer and C.W. Smith (eds). Gouvernement de Polynesie fran$aise/university of Hawai'i at ManoaICentre ORSTOM de Tahiti. Meyer, J.-Y., 1994, Mecanismes d'invasion de Miconia calvescens DC. en Polynesie Franqaise. Ph.D. thesis. Academie de Montpellier - Sciences et Techniques de Languedoc, Universite Montpellier pp.

56 Meyer, J.-Y., Status of Miconia calvescens (Melastomataceae) in the Society Islands (French Polynesia). Pacific Science. 50: Ramadan, M Trip Report, HDOA files. Singh, B. P., High security containment facilities in the United States for fungal plant pathogens of quarantine significance. pp , In: Containment Facilities and Safeguards for Exotic Plant Fathogens and Pests. R.P. Khan and S.B. Mathur (eds.). APS Press, St. Paul. Tanji, E., Governor declaring war on alien tree. Honolulu Advediser. April 8: A-3. Tanji, E., Volunteers tackle foreign invader. Honolulu Adverfiser. April 14: A p~ Wagner, W. L., D. R. Herbst and S. H. Sohmer Manual of flowering plants of Hawai'i. University of Hawai'i Press and Bishop Museum Press. Honolulu. Wapshere, A. J., A strategy for evaluating the safety of organisms for biological weed control. Annals of Applied Biology 77: Watson, A, K., Host specificity of plant pathogens in biological weed control. pp , In: Proceedings of the IV Symposium of the Biological Control of Weeds, August 19-25, E. S. Delfosse (ed). Agriculture Canada, Vancouver, Canada. Watson, A. K., The classical approach with plant pathogens. pp. 3-23, In: Microbial Control of Weeds. D. 0. TeBeest, (ed). Chapman and Hall. New York. Yohay, J. B. and B. Fukutomi, At war with a plant. Honolulu Sfar Bulletin. May 22: A-9.

57 BIOLOGICAL CONTROL OF GORSE IN HAWAI'I: A PROGRAM REVIEW - -4 George P. arki in,' Patrick on ant,^ Eloise ~ ill~ore,~ and Ernest yoshioka4 1 USDA Forest Service, Forestry Sciences Laboratory, Rocky Mountain Research Station, 1648 South 7th Avenue, Bozeman, Montana gmarkinafs. fed. us 2 Hawai'i Department of Agriculture, 16 East Lanikaula Street, Hilo, Hawai'i miconia@aloha. net 3 Hawai'i Department of Agriculture, 1428 King Street, Honolulu, Hawai'i Emall: elolsekillgore@yatioo. corn Hawai'i Department of Agriculture (RZired),?BEaSfLanlltauEStmtIl;rCIo~Hawai'i Abstract. Gorse (Ulex europaeus), a spiny, leguminous shrub, has invaded pasturelands and natural ecosystems on Maui and Hawai'i. An interagency effort to implement long-term control of gorse included support for a biological control effort. Between 1984 and 2000, seven insect natural enemies and one plant pathogen were tested, six of which were eventually released in Hawai'i. This paper reviews the history, organization, and cost of this program and the lessons we learned in an attempt to identify information that might be useful in planning similar, future programs. Keywords: Apion scutellare, A. u/icis, Agonopterix ulicetella, Anisoplaca ptyoptem, Chlorophorus ttifasciatus, Cydia lathyrana, Dictyonota sfrichnocera, Pempelia genistella, Sericothrips staphylinus, Sitona spp., Tetranychus linteanus, Ulex europaeus, Uromyces pisi f. sp. europaei. INTRODUCTION Gorse (Ulex europaeus L.; Fabales, Fabaceae), a spiny, leguminous shrub from Western Europe, was used extensively to form hedges for containing livestock before the invention of barbed wire. Gorse was distributed widely throughout the world for this purpose but in almost all new localities it quickly escaped from cultivation and became a serious weed (Holm et al. 1979). It probably was introduced to Hawai'i around the turn of the century (Degener 1975) and by 1925 was recognized as a serious weed on Maui. At that time, biological control was attempted but none of the introduced agents established (Julien & Griffiths 1998). By the 1950s, the change from sheep- to cattleranching on the island of Hawai'i resulted in the realization of gorse as a major weed and another biological control program was undertaken. Fourteen insects were evaluated; most could not be reared in quarantine or failed specificity testing. Only three were released, all weevils of the genus Apion (Chrysomelidae: Curculionidae). Qnly the seed weevil, A. ulicis (Forster), became established on Maui but with no noticeable impact on the spread of gorse (Markin & Yoshioka, 1989). In the absence of an effective complex of biological control agents, prisoners stationed at the Olinda correctional facility were used to control gorse on Maui by manual removal and by planting pines as shade trees. On the island of Hawai'i, chemical control was undertaken between 1976 and 1978, funded through the federal Comprehensive Employment Training Act. This program was so successful that by

58 1980, gorse was considered controlled and further management efforts dropped on Hawai'i. Unfortunately, no one considered the long-lived seeds in the soil. By 1983, gorse had recolonized the entire original area. In 1984, Department of Hawaiian Home Lands and Parker Ranch attempted to organize a new gorse management program, which included a renewed effort to develop effective biological control agents. By 1996, initial work to find, test, and release a new complex of insect agents had been completed; at least four insect biological control agents were established which attacked different parts of the plant (Markin et el. 1996). A plant pathogen was released in early The program has now shifted to monitoring the impact of these agents on gorse. A description of the agents and their release in Hawai'i has been presented elsewhere (Markin et a/. 1996). The purpose of this paper is to review the history and organizaticuwf-theprogramand-to-identif~thelessons-learneccin-conductinga-- biological control program in Hawaiian natural ecosystems. HISTORY OF PROGRAM: On October 27, 1983, the "Big Island Resource Conservation and Development Committee", a local program of the USDA Soil Conservation Service (SCS), met at Mauna Kea State Park to discuss the spread and management of gorse on the Big Island. The meeting was followed by a field trip to the Humu'ula infestation on the southeast slopes of Mauna Kea (for a map of the gorse infestations in Hawai'i, see Markin etal. 1988). The committee was so impressed by the massive resurgence of a plant everyone believed had been controlled that they formed a gorse-control committee to look into the implementation of a new management program. In recognition of the fact that herbicides would probably be ineffective in limiting the spread of gorse because of the massive seed bank, the committee recommended a renewed biological control effort. The first official meeting of the Hawai'i Steering Committee on Gorse Control was held in The Committee reviewed research results including testing of new herbicides, management through burning and grazing, biological control, and a longtern1 integrated control program. The Committee comprised representatives from Hawaiian Homelands, Parker Ranch, several adjacent ranches infested or threatened by gorse, Hawai'i Department of Agriculture (HDOA), the Hawai'i Division of Lands and Natural Resources, and the U.S. Army Pohakuloa Training Area. The USDA-SCS Resource Conservation and Development (RC&D) Office at Waimea accepted the committee and its program as an official RC&D program, allowing the Committee to solicit funds, write contracts, and submit grant proposals. For the first year, most effort focused on increasing local awareness of the problem with some attempts at dlrect control and containment. A previously released agent, the gorse seed weevil (A. ulicis), previously established on Maui, was introduced to Hawai'i (Markin & Yoshioka 1989). Ernest Yoshioka, HDOA entomologist on Hawai'i with previous gorse experience during the 1950's biological control effort and George Markin, entomologist with the USDA Forest Service Institute of Pacific Island Forestry (IPIF) became involved in the gorse control project at this time. While primarily a weed of pastures, gorse also was invading the lower edge of the pukiawe shrub zone on Mauna Kea and its seeds were carried down watercourses into the lower elevation rain forest. Therefore it was judged a suitable weed for study by IPIF. The National Park Service (NPS) was interested in

59 supporting the program also because gorse was an invasive weed in Haleakala National Park on Maui. Because HDOA had been unable to rear gorse insects in their Honolulu quarantine facility, the gorse biological control agents were evaluated in the new high-elevation quarantine facility at Hawaii Volcanoes National Park. In the 1980's, the most active biological control program on gorse was being conducted in New Zealand (NZ) under the leadership of Dr. Richard Hill, NZ Department of Scientific and Industrial Research (DSIR, presently Landcare Research). From field exploration in England, he had selected ten insects with the most potential as biological control agents of gorse (Hill 1982). NZ was supporting initial evaluation of several agents in England and Agonopterix ulicetella (Stainton) (Lepidoptera, Oecophoridae) was already in quarantine. In 1985, an informal cooperative effort with New Zealand was established and the first shipment of A. ulicetella arrived in Hawai'i in By 1986, the Gorse Steering Committee had increased to 15 active members, mostly local landowners and representatives of state and federal land management agencies, with a mailing list of over 50 interested participants on Maui and Hawai'i. The Committee actively supported biological control. Grants from the County of Hawai'i and U.S. Fish and Wildlife Service [USFWS]) were used to rear, screen, and test A. ulicetella and other potential gorse biological control agents. HDOA directed the program as a continuation of earlier biological control efforts against gorse, and selected test procedures and species for specificity tests. In 1987, another small grant was received from the County of Maui, and the State of Oregon became involved as a partner in Gorse is a major problem along the west coast of Oregon where it hinders forest management (Hermann and Newton1968) and recreation and creates a significant fire danger (Holbrook 1943). By this time, the Gorse Steering Committee had obtained two influential members: Ken Autry from the USDA-SCS office in Waimea provided organization and dynamic leadership and Francis Pacheco, a local consultant for the sugar industry, brought the Committee political contacts within the state. Under the guidance of these two sometimes-conflicting personalities, the Gorse Steering Committee undertook new public education campaign through newspaper releases, public field days, and an aerial tour for legislators. Through this effort, the Committee was able to attract the support of local state legislators who facilitated its 1988 approach to the Governor's Agricultural Coordinating Committee (GACC) and the legislature for funding. With wide public awareness, support of local legislators, and testimony from the Gorse Steering -emmittee;-the-bill-passed-an&wasf ully-f und~kesestatefunds-werem~eed_~rrr exceeded by IPlF and NPS contributions in salaries and facilities. Hawai'i now was able to participate in the development of biological control agents in Europe. Hawai'i and New Zealand established a formal agreement and funded Commonwealth Agricultural Bureau (now CAB1 Bioscience) to conduct the needed studies. By supplementing the research funding from NZ, a member nation of CABI, Hawai'i and Oregon were able to support more research in Europe than would have been possible otherwise. The first new agent, A. ulicetella, was released in the fall of IPIF, in cooperation with New Zealand, coordinated the foreign work, conducted the final host testing in quarantine in Hawai'i, and obtained release permits. HDOA established mass rearing facilities to produce large numbers of insects, which were released throughout gorse infestations in Hawai'i. Permanent study plots were set up to monitor growth of gorse and impact of the biological control agents.

60 The next agent, the gorse thrips, Sericothrips staphylinus Haliday (Thysanoptera, Thripoidae) was released in At about this time, two agents were rejected because they showed some ability to feed on two native trees, koa (Acacia koa Gray - Fabales, Fabaceae) and mamani (Sophora chrysophylla (Salisb.) Seem. - Fabales, Fabaceae) (Table 1). In 1991, the program was delayed when HDOA's Plant Quarantine Branch stopped,celeases of all new weed agents while new regulations were written and implemented. he new regulations, in place by 1994, established the requirement of a federal environmental assessment for all new releases and increased the permit review time from six months to 1-2 years. Under the new review process, the gorse spider mite (Tetranychus lintearius (Dufour) - Acari, Tetranychidae) was released in 1995 and the moth, Pempelia genistella (Duponche) (Lepidoptera, Pyralidae), in Table 1. Summary of insect biological control agents in et a/. (1996). Agents Year Year Status Released Established hsaaesw Apion (Exapion) ulicis Apion (Perapion) scutellare Agonopterix ulicetella - Sericothrips staphylinus Tetranychus lintearius Pempelia genistella) Dictyonota strichnocera Anisoplaca ptyoptera Not 1984* % of pods attacked 1989 Not established Well established Established, spreading Well established 1996 Not established Not released released Uromyces pisi t.sp. europaei 2000 Fate unknown R~rt Cydia lathyrana (root moth from England) -Sitmmsppfi-(foot weevilhrom-england) Chlorophorus trifasclatus (root-feeding beetle from Portugal) Released on island of Hawai'i, already established on Maui. Unfortunately, by the time the new regulatory process was implemented, the state was encountering severe financial problems and in 1993 the legislature stopped funding the program. Several root-feeding insects whose development had been delayed were therefore never tested (Table 1). Loss of funding greatly reduced the HDOA effort toward mass rearing, release, and redistribution of agents in the field and halted a long-term monitoring program. With IPlF end Oregon state funding, the gorse program was able to obtain release permits for the last two agents. In 1995 the mite, T. /inteaflus, was released from quarantine and further work in Hawai'i discontinued. Quarantine work on the last insect, P. genistella, was continued at Bozeman, Montana

61 during and testing of new insects discontinued after the release of this agent in During this period HDOA constructed a new plant pathogen quarantine facility at Honolulu. One of the first pathogens to be brought into it was Uromyces pisi J. Schrot. f.sp. eumpaei (Uredinales, Puccinaceae), a rust fungus obtained from England. This agent was released in the spring of At least four of the agents are now established (Table 1). Superficial observations from entomologists and land managers familiar with the Mauna Kea gorse infestations suggest that the biological control agents may have reduced flower production and annual shoot length. Plants frequently appear sickly and yellowing with numerous dead and dying branches often covered with webbing from the mite. The ultimate impact of these agents probably will not be known for another 5-10 years. CONCLUSIONS While it is too early to determine the success of this program, the original goal of finding, testing, and establishing a complex of at least four biological control agents in Hawai'i was accomplished. We can, however, estimate what a new biological control program might cost, how long it might take, and identify information that might be useful in planning, organizing, and conducting programs in Hawai'i. Cost. Establishing the cost for the insect portion of this program is difficult because of the many different sources of funding that supported it and the contributions in salary, time, and materials made by the different agencies. A rough breakdown over the 11-year period indicates that the insect work required almost $1,500,000 (Table 2). An additional $200,000 was spent over 7.5 years evaluating the insect pathogens, for a total cost of roughly $1,700,000. Cooperation with NZ yielded an additional $1 million benefit, since they paid the cost of all the preliminary work in Europe to find, select, and study the agents that were eventually brought into our quarantine. Also, utilizing the data obtained in NZ's host testing of these agents significantly reduced quarantine studies. Finally, an additional $250,000 would probably have been necessary to run a long-term post-release monitoring study to complete this program. A similar biological control program on a totally new weed of Hawaiian natural ecosystems is expected to cost around $3 million. While this may seem high, it falls -within_the~rangeof_es~i~ates-for-o~e~weed~iolo~~l~~oj~~ogcam~esti costs for a complete weed biological control program 20 years ago were between $1 to 2 million (Andres 1977, Harris 1979). Conclusion: To undertake a totally new weed biological control program in Hawai'i will probably cost around $3 million. Time. The insect component of this program took over 11 years from its conception in 1984 until the release of the last insect in During this period, two years' delay were necessitated while the governing regulations were changed. An additional year's delay occurred due to a request by USFWS for additional testing of endangered species of Hawaiian plants. However, the program was shortened by the fact that NZ had previously spent several years doing the preliminary studies necessary to identify the natural enemies of gorse. Quarantine evaluation of the species proceeded fairly

62 Table 2. Program Costs. Estimates of funding or values of contributed services that supported the insect portion of the Hawai'i Gorse Biological Control Program from U.S. Forest Service, Institute of Pacific Island Forestry (estimated that 80% was for salaries) $ 775,000 National Park Service Contribution (Operation, Electricity, and Maintenance of Hawai'i Volcanoes National Park Quarantine) $ 45,000 Salaries, Hawai'i Department of Agriculture, Plant Pest Control Personnel. Hilo $ 121,000 State of Hawai'i, Legislature-appropriated Funds $ 450,000 Oregon Department of Agriculture $ 50,000 Use of Montana State University Insect Quarantine Facility to study and ship two agents to Hawai'i $2aMQ Outside Grant $ 35,000 TOTAL $1,496,000 smoothly, each taking 2-3 years. Initially, approval for their release could be obtained in as little as 6 months. However, with the need now to do an environmental assessment and with the new regulations that allow outside agencies such as the USFWS to request re-testing or additional testing, it is expected that each insect would now require 3 to 5 years. While the scientific work and review process for each agent proceeded reasonably smoothly, this long time span (11 years) had several major undesirable effects. The program was totally dependent on the gorse steering committee to provide the political --suppoat~raisemo~ay~~~~9~19~o~tbete~wa~~excellent support from this - committee, but once money from the state had been obtained and the first agents were in the field, interest and participation in this committee dropped off. When the budget - crisis hit Hawai'i in 1993, the strong local committee needed to see that the program continued was no longer available. The second problem was that the legal regulations under which this work was conducted constantly changed in response to interacting laws and regulations. Conclusion: Future programs (at least the finding, testing, and release of the new agents) should be tightly organized and conducted within as short a timeframe as possible. Drawing out the timeframe will allow burnout and loss of your local outside supporters and expose the program to changes in regulations, causing delays and increasing costs. Ideally, the testing in quarantine, even if it means rearing and testing a large number of different species of insects simultaneously, and the approval process should be concentrated, if at all posslble, In a 5-year period.

63 Steering Committee. The chance of finding a single, permanent, long-term source of funding for a biological control program for a weed of Hawaiian natural ecosystems is probably impossible Therefore, the need to locate and use multiple sources of funding will probably be the norm. The most effective approach is by means of a local steering committee composed of land managers, landowners, and other interested parties who are already fighting the weed and willing to commit their time and effort to fund raising. Any weed bioloqical control program needs the political support of the local community, therefore, anotner function of the steering committee is education and increasing public awareness. The steering committee can also coordinate the work of different agencies involved. Besides supporting biological control, the gorse steering committee supported testing other management efforts, including testing of new herbicides, shading by reforestation, effectiveness of burning, grazing by goats, and the use of different grazing regimes. The long-term solution to the gorse problem in Hawai'i will probably require a combination of several management approaches. Conclusion: Local land managers and private landowners should be recruited into a steering committee during conceptual discussions of a new biological control program to solicit the necessary funding and provide support to the scientists. Leadership. Researchers should not be expected to provide leadership for multi-agency, politically driven programs such as the gorse program. They are too involved in day-to-day work with insects and the research involved. There is also a potential conflict of interest. The outside leadership contributed substantially to the success of the scientific program providing political support, obtaining funding, maintaining a focus in the research and demanding results and reports. The success was largely the result of the commitment of the steering committee, particularly the chairman. Conclusion: A successful program needs leadership provided by well-informed, politically savvy outsiders (non-researchers) committed to seeing the program succeed. Outside Cooperators. The complexity of the scientific research that identified, evaluated, and tested the complex of insects required the involvement of many cooperators in other countries. Previous work in NZ and England and cost sharing considerably benefited this project by saving time and research. Finding another country that was interested in gorse -contcol~r~nz~nccrunninga-closely-~~~~dina~ed,hi~y_(1~~~cati~e-p~o~r them is probably one of the major factors that contributed to our success. Conclusion: Look for outside cooperators. Lead Scientist. The studies necessary to progress from locating a natural enemy in its homeland to its release as a biological control agent in the field in Hawai'i have become so complicated, time-consuming, and costly that conducting a program for a single weed can demand the full time and attention of the responsible scientist. The majority of the time involved in a new biological control program will be spent in interaction with other people such as members of the local steering committee, foreign scientists, and the administrative bureaucracy that must be navigated to obtain permission to ultimately release the new agents. Finally, the scientist in charge must be able to train and supervise the technicians who will do most of the routine handling of the Insects, from

64 their arrival in quarantine to their release. Conclusion: Each weed targeted for biological control needs a single, full-time scientist responsible not only for the necessary entomological studies, but for coordinating and guiding all stages of the program. Since overall administration and coordination will be more time-consuming and critical than any single, scientific study that might be conducted, the lead scientist should be judged on the number of new biological control agents released, established in the field, and attacking the weed, instead of on the number of peer-reviewed papers published in a scientific journal. Expect outside criticism. While in general the program experienced excellent local support, there was criticism. In conducting biological control, it is common to take the shortsighted view that it is just another management tool. It is difficult to realize that many people outside the field do not understand the goals, and through ignorance, fear, or for personal motivations, will attack it. During this program, Howarth (1983, 1991) published his articles questioning the safety of biological control. He primarily looked at problems with many of the earlier biological control programs aimed at insects and did not address weed biological control, however, several mainland scientists used his findings to question the practice of weed biological control in general, and this program specifically. These outside criticisms were beneficial in that they required a re-examination of the program, testing procedures, and the need to educate another group of people, outside scientists. The second objection came from the USFWS, some members of which felt that under the Endangered Species Act insufficient attention was paid to the potential threat to endangered plants in Hawai'i. Their objections did not significantly harm this program - just necessitated that another group of plants be included in the host range testing - but it did emphasize that the regulations under which biological control is conducted are not fixed in stone but are constantly changing. Conclusion: A continually new audience of people are watching and reviewing the work and will be questioning its values and safety. Future biological control of weeds programs, therefore, must expect some criticism, be flexible enough to identify the basis for the attacks, and be prepared to work to resolve them. LITERATURE CITED Degener, Plants of Hawaii National Park illustrative of plants and customs of the South Seas. Ann Arbor, MI: Braun Broomfield, Inc. 312 pp. Harris, P Cost of biological control of weeds by insects in Canada. Weed Science. 27: Hermann, R. K, and M. M. Newton Tree planting for confml of gorse on the Oregon coast. Research Paper 9. Oregon State University, Forest Research Laboratory, Corvallis, OR. Hill, R. L The phyfophagous fauna of gorse (Ulex eumpaeus L.) and host plant

65 quality, Doctoral dissertation, Imperial College, University of London, Silwood Park, Ascot, U.K. Holbrook, S. H The gorse of Bandon. Chapter 14, In: S. H. Holbrook (ed.), Burning an empire. Macmillan Press, London. Holm, L. G., J. V. Pancho, J. P. Herberger, and D. L. Plucknett A geographic atlas of world weeds. John Wiley and Sons, NY. Howarth, F. G Classical biological control: panacea or Pandora's box. Proceedings, Hawaiian Entomological Society. 24: Howarth, F. G Environmental impacts of classical biological control. Annual Review of Entomology. 36: Julien, M. H., and M. W. Griffiths. eds Biological control of weeds. CAB1 Publishing, Brisbane, Australia. Markin, G. P., L. A. Dekker, J. A., Lapp, and R. F. Nagata Distribution of gorse (Ulex europaeus L.), a noxious weed in Hawaii. Newsletter, Hawaiian Botanical Society. 27: Markin, G. P., and E. R Yoshioka Present status of biological control of the weed gorse. pp , In: E.S. Delfosse (ed.), Proceedings: VII International Symposium on Biological Control of Weeds, March 6-1 1, lstituto Sperimentale per la Patologia Vegetale, MAF, Rome. Markin, G. P., E. R. Yoshioka, and P. Conant Biological control of gorse in Hawaii. pp , In: V.C. Moran, and J.H. Hoffman (eds.), Proceedings: IX International Symposium on Biological Control of Weeds, January 19-26, University of Cape Town, Stellenbosch, South Africa.

66 SETTING PRIORITIES FOR THE BIOLOGICAL CONTROL OF WEEDS: WHAT TO DO AND HOW TO DO IT Judith H. Myers and Jessica Ware Centre for Biodiversity Research, Dept. Zoology and Faculty of Agricultural Sciences, 6270 University Blvd., University of British Columbia, Vancouver, V6T 124, Canada Ernail: ubc.ca Abstract. Three options are available for dealing with non-indigenous plant species that either may become or already have become invasive weeds; keep them out, eradicate introduced populations while they are still small, or finally attempt biological control of established populations. By far the best approach to controlling potentially invasive foreign weeds is to limit the introduction of plants to new areas. Better communication of the consequences and environmental costs of these species may help balance the pressure applied on regulatory agencies by Industries to permit commercial plant imponatlons under lew limitations. Eradication attempts must be bold and fast. Proponents of the program should not make unrealistic promises because eradication is so difficult to achieve. Finally, biological control does have a potential role in the management of non-indigenous weeds. However, finding agents that are capable of reducing the densities of plants is not an easy task. Successful biological control agents are capable of killing or greatly reducing the vigor of their host plants at life stages for which little compensation can occur. Greater focus on efficacy can help reduce the number of non-indigenous species that are introduced in biological control prngrams Keywords: eradication, invasive plants, seed predators, plant introductions, quarantine, noxious weeds INTRODUCTION Over the last 500 years transoceanic travel and commerce has led to a global redistribution of non-native plants (Moody and Mack 1988). Without natural enemies, many alien plants have established, invaded and displaced native vegetation (Mack et a/. 2300). Three options are available for dealing with alien plant species that either may become or already have become invasive weeds; keep them out, eradicate introduced populations while they are still small, or finally attempt biological control of established populations. PRIORITY ONE - KEEP THEM OUT Although exclusion is the most effective way to prevent potentially invasive weeds, regulations to stop the introduction of weeds has been woefully ineffective. In the USA at least 2000 non-native plants are invading managed and natural systems. This includes at least 235 woody plants and 600 herbaceous plants, including grasses and aquatic species (Reichard and Campbell 1996). A majority of non-indigenous weeds were introduced intentionally to areas where they were not native and where they have become serious environmental or agricultural pests. In the USA 85% of the 235 species of woody plant invaders were introduced as ornamentals or for landscaping (Reichard and Campbell 1996). In Australia approximately 46% of noxious weeds have been introduced for ornamental or other purposes (Panetta 1993). In the city of Zurich alone 300 plant species have naturalized, 52% for ornamental purposes, and these are

67 thought to have led to the disappearance of more than 150 native species (Landolt 1993). It is not surprising that the types of plants valued by horticulturists are also those with characteristics that preadapt them to be weeds. Species favored by horticulturalists plants are those that produce many flowers, begin to flower early in the season, are easy to propagate, and that grow well in disturbed sites (White and Schwarz 1998). The prevention of weed introductions therefore creates a tension between agencies regulating plant introductions and the horticultural and agricultural industries. In Australia the government restricts the entry of plants via the Quarantine Act of 1908 that prohibits taxa from 19 genera and 66 species (Panetta 1993). However, plants being introduced by nurseries and the gardening industry are not included on these schedules. Given the pressure by commercial ventures to introduce foreign plants, and the need for quarantine regulations to protect against invasive weeds, a procedure for predicting the potential invasiveness of non-indigenous plants is required. Schemes for assessing plant species prior to introduction have been proposed by Panetta (1993), Reichard and Hamilton (1996), and White and Schwarz (1998). White and Schwarz (1998) compare the traits of plants desired by gardeners and those of invasive weeds. They list the following tra~ts to be in common; rapid growth, early and many flowers, prolific seed production, good seed germination, and no major pests. Adaptations for efficient dispersal and vegetative spread are also likely to apply to both situations. Relchard and Campbell (1996) developed a scheme for predicting the invasiveness of plants by comparing the traits of 235 species of plants known to be invaders to those of 87 noninvasive plants. These comparisons were based on plant growth rates, juvenile penods, germination requirements and the ablllty to reproduce vegetatively. Under this system plants can be categorized into those to be rejected, accepted or held for further examination. White and Schwarz (1998) tested the ability of Reichard's scheme to predict the lnvasiveness of known plant invaders and found that 85% would have been rejected by the scheme, 13% would have been held for further examination and 2% would have been accepted. Panetta (1993) proposed a scheme based on earlier work of (Hazard 1988). He assigned a point value to different characteristics; plants receiving a value of twenty or more points are rejected while those with a value of 12 or less are accepted, and those in-between are further investigated (Table 1). This system rejects outright aquatic plants, potentially causing friction with the major industry selling aquatic plants for aquaria and ponds. Another system for e v a l u a t i n g a n t s IS he Amlian Weed risk assessment scheme proposed by Pheloung (1995 cited in White and Schwatz 1998). This system relies on a number of plant attributes including whether the plant is a known invader, as well as other biological characteristics having to do with climatic requirements, reproduction, dispersal, persistence, noxiousness, and distribution. lnvasiveness elsewhere is also considered. Overall there are 49 questions divided into 8 categories. Nonweedy traits receive a score of 0 or -1, unknown traits a score of 0, and weedy traits a score of 1. Some scores are weighted differently depending on the answer to the question. Plants receiving a score of 0 or less are considered safe for introduction while those with a score greater than 7 are considered to be potentially weedy invasives. This system focuses on vegetative growth and the ability of plants to tolerate a range of conditions and high levels of damage. It also includes characteristics such as the possession of parasites, toxicity and the seed type produced.

68 White and Schwarz (1998) tested the ability of this system to reject plant species already known to be invasive in Australia and of the current invaders, 84% would be rejected by this scheme, 16% fell into the category of requiring future study and none would have been accepted. More recent versions have questions dealing with dispersal attributes. - Criterion Is the species free-floating aquatic or can 20 it survive and reproduce as a free-floating aquatic Is it a weed elsewhere 20 Are there close relatives with a history of 10 invasion to similar habitats Is it spiny 10 Are diaspores spiny 10 Is the species harmful to animals 8 Does the plant produce stolons 5 Does the plant reproduce vegetatively 8 Are diaspores wind-dispersed 8 Are diaspores dispersed by mammals or machinery 8 Are diaspores dispersed by water 5 Are diaspores dispersed by birds 5 Point value Table 1. Evaluation scheme proposed by Panetta (1993) to predict potential invasiveness of plants. These evaluation schemes may not be perfect but they do suggest criteria that could be used effectively to slow the continued introduction of potentially invasive plank.-tbeceis-a-great-needto-apply_politicalpressll[~e~to~~h~n~_egulat~ns~on~tbe~~ purposeful introduction of plants. Currently the interests of the nursery and ornamental plant industry are served with little regard for the environmental impacts of invasive, non-indigenous species. Greater publicity on the cost of these weeds, and better education of landscape architects, plant breeders, home and commercial gardeners, pet store owners and those with aquaria and garden ponds are a necessity. PRIORITY TWO - ERADICATION Following the introduction and establishment of a non-indigenous plant there may be a short time-window in which the species might be eradicated (Myers et a/. 2000). Eradication is particularly difficult for plants that produce many seeds because dispersal can be rapid. Also the establishment of a long-lived seed bank makes total elimination difficult and continued vigilance over many years imperative. Usually the opportunity

69 for eradication is lost by the time the problem is recognized and the project considered or finally put into place. A vivid example of a lost opportunity was the failure to eradicate the tropical marine alga Caulerpa taxifolia (Vahl) (Chlorophyta, Chlorophyceae) from Monaco where it was first recognized in 1984 (Meinesz 1999). Eradication was called for in 1991 but to no avail. This "aquarium" plant is now widespread in the Mediterranean where it forms dense stands. Successful eradications of small populations of recently introduced nonindigenous species may not be recorded in the literature and therefore it is difficult to judge how often this is successful. One such success in southeastern Queensland was the eradication of Eupatorium serotinum Michx. (Asterales, Asteraceae) in the 1950's (R. McFadyen pers. comm.). An on-going project in Australia is the attempt to eradicate Siam weed, Chromolaena odorata (L.) R.M. King and H. Robinson (Asterales, Asteraceae). Although densities have been greatly reduced, and the distribution has been limited to a 50 km radius, total eradication will be a slow process (R. McFadyen, personal communication). In a recent review (Myers et a/. 2000) 6 factors were proposed as necessary for a successful eradication program: 1) Sufficient resources to complete the project; 2) Clear lines of authority for decision making; 3) A target organism for which the biological characteristics are compatible with eradication (easy to find and kill, no seed bank); 4) Easy and effective means to prevent reinvasion; 5) Easy detection of plants at low densities; and, 6) Plans for restoration management if the species has become dominant in the community; there is little value in replacing one weed with another. For widely established weeds, area-wide management may still be possible. This will involve continuous efforts to suppress populations of the plants chemically and mechanically in all locations. Working along the borders of the plant distribution may help to reduce the spread of the invasive weed, but metastatic spread of an invasive species following seed dispersal by animals or movement of plants by human activities works against successful containment. In conclusion, rapid action following the identification of a newly established species may allow successful eradication, but procrastination can cause the window of opportunity to slam shut. For well established non-indigenous species biological, chemical, or mechanical control are the only mechanisms to reduce plant vigor and density. In most instances, chemical and mechanical control are too expensive and damaging to other members of the plant community and to the environment for widespread use. Although biological control usually is better focused on the target weed species than are the other control procedures, it does require the introduction of another species. In addition, in several cases biological control agents have moved onto non-target species of native plants (Louda et a/. 1997, Louda 1999, Pemberton 1995). Therefore, careful consideration must be given to which species of biological control agents are introduced. Each introduction of an insect or plant disease will carry with it some chance that an unwanted non-target impact will result (Cory and Myers 2000, Follett and Duan 1999).

70 Selecting those species of natural enemies w~th the greatest potential for success is a challenge to the biological control practitioner. Biological control, if successful, will reduce the density of the plant to a level at which other control is not required (McFadyen 2000), but it will not eliminate the weed species totally. However, biological control is not always successful. Estimates of how successful biolog~cal control is have varied from 10 to 30% of the weed species for which it has been attempted (Crawley 1989, McFadyen 1998, Myers, et a/. 1988) to 80% success in Australia and South Africa (McFadyen 2000). Some of thrs variation may be Influenced by how success is evaluated. And how much effort has been put into programs. If successful control requires a whole complex of natural enemies to reduce the density of the host plant populations, achieving success may be slower and more difficult than if single agents are able to reduce the densities of the target weeds In an attempt to evaluate the question of whether a complex of agents is necessary for successful biological control, several studies have examined successful biological control programs recorded in the literature to determine whether success was attributed to several agent species or to just one. In the first of these studies (Myers 1984), 81% of successful biological control programs were attributed to one species of agent. In a more recent review (McFayden 2000) 41 % of 41 successful biological control programs of weeds involved only one agent or success was attributed to one agent. Another study, based on data from Julien and Gnffrths (1998), found that 54% of programs involving the introduction of several agents attributed success to a single agent (Denoth et al. in press). These studies are difficult to interpret because most often careful evaluation of the impacts of the various agents is not done. Therefore, attributing success to a particular agent or group of agents may be a bit arbitrary. There may be a tendency for biological control practitioners to attribute some success to every agent that has been introduced. This may explain why of 8 biological control successes recorded for Hawai'i (Opuntia cordobensis, Spegazzini (Caryophyllales, Cactaceae), 0. fiscus-indica (L.) Miller, Ageratina riparia (Regel) R.M. King & H. Robinson (Asterales, Asteraceae), Emex spinosa (L.) Campd. (Polygonales, Polygonaceae), Rubus argutus Link (Rosales. Rosaceae), Tribulus cistoides L. (Zygophyllales, Zygophyllaceae) (native) and T. tenestris L.) only 2 weeds (25%) are thought to have been controlled by a single agent and the other 6 successes, including the control of a native species, are attributed to a combination of agents (information from (Julien and Griffiths 1998)). This contrasts to 8 successful weed control programs in South Africa for which success in 5 programs (62%) is attributed to a single agent (Olckers and Hill 1999). --Histo~i~a~ly-onavgrage-5t~agent~havebeeach biological control program although some weed species such as lantana have been the target for over 20 species of natural enemies (Broughton 2000). Of the thousands of biological control agents introduced globally, only about 10% have had sufficient impact on the host plants to be considered effective. The record of outcomes of agents introduced for biological control of weeds in Hawai'i is shown in Figure I based on data reviewed by Julien and Griffiths (1998). This review of introductions and successes in biological control indicates that a number of non-indigenous agents are being introduced to control other non-indigenous species. Because the introduction of each species is associated with the possibility that it will have non-target impacts, it is important to be parsimonious in choosing agents for introduction. If certain types of potential biological control agents have had a poor record of success in the past, they should probably not be considered for introduction in future programs. We propose that one group of natural enemles that

71 are unlikely to have much impact on host plant density are those that merely reduce seed production. Figure 1. Fate of the 81 species of agents introduced to Hawai'i for the biological control of weeds. Not established Successful Other Seed predators are unlikely to be successful biological control agents because seedling survival is frequently related to the density of the seeds; high densities survive less well than low densities. This principle of "self-thinning" is well known in plant ecology (Silverton and Lovette Doust 1993). The ability of plants to compensate for reduced seed production and lower seedling numbers makes the impacts of biological control programs difficult to predict (Myers ef al. 1988). Most serious weeds have highseed production and therefore are likely to be able to absorb high seedling mortality from effective and/or numerous seed predators. Therefore, it would seem that seed predators have little potential as biological control agents for plants that are able to compensate for the loss of seeds and for those for which seedling establishment is limited by the number of "safe sites" available (Andersen 1989). Although seed predators may not reduce the density of invasive weeds it is a widely held view that they may slow the spread of the target plants. In South Africa biological control practitioners consider seed predators to be useful in programs that use both chemical and mechanical control in addition to biological control (Impson et a/. 1999). However the contribution of seed predators in these programs has not been evaluated. If the spread of plants is by diffusion, reduced seed production is more likely to be translated into a reduced rate of spread than if plants disperse as a metastatic process, with new establishments occuning outside the initial introduction

72 site and serving as new foci for spread of the species (Clark et a/. 1998, Kot et a/. 1996, Moody and Mack 1988). It cannot be assumed that seed predators will have a measurable impact on the rate of spread of plants. However, experimental analysis of this could be very useful for target weed species. One way to evaluate the effectiveness of seed predators as biological control agents is to determine if they ever have been successful. Tephritid flies are seed predators, and they have been introduced in 25 biological of weed programs (Julien and Griffiths 1998). They never have been shown to be successful control agents. A review of South African weed control programs lists seed predators as only being successful when in combination with other agents (Olckers and Hill 1999). In these programs stem borers were the most successful agents followed by sap-suckers. Rees and Paynter (1997) developed a model of scotch broom, Cystisus scoparios (L.) Link (Fabales, Fabaceae), from which they concluded that a reduction in plant fecundity could reduce broom density when the disturbance rate is high, and plant fecundity and seedling survival low. However, these situations do not hold for most introduced populations of broom and Paynter eta/. (1996) concluded that seed predators were unlikely to reduce broom populations in New Zealand. They did suggest that seed predators might slow the spread of the species, but this is contradicted by observations in Oregon where the introduced ~nsect Exapion fuscirostre (F.) (Coleoptera, Curculionidae) reduced seed production by 85% but did not reduce either broom density or spread (Andres and Coombs 1992). A recent matrix model of scotch broom showed that in prairie in Washington State, USA 99.9% of the seed would have to be destroyed to suppress invasion of the plant, but in urban sites with poor soil and disturbance only 70% of the seeds would have to be reduced to slow invasion (Parker 2000). These studies suggest that seed predators are not likely to be effective biological control agents for broom. Several studies of native plants have indicated a relationship between seed predators and plant recruitment and density (LOuda 1982a, 1982b, 1983, 1999, Louda and Potvin 1995). This difference in the impact of seed predators on populations of introduced and native plants may be related to the role of competing plant species in the native plant communities. Serlous weeds often occur at such high densities that intraspecific competition is more important than interspecific competition. The potential relevance of competition to the impact of seed predators is seen in the one example that we know of in which biological control success has been attributed to a seed feeder. This is the control of nodding thistle, Carduus nutans L. (Asterales, Asteraceae), in North America by the weevil Rhinocylus conicus Froelich (Coleoptera, - Curculionidae) (Harris 1984, Kok and Surles 1975), a biological control agent that has also been shown to have an impact on rare, native thistles (Louda 1999, Louda and Potvin 1995). Nodding thistle is an annual plant and depends on disturbance for establishment, but once established it can dominate a site, at least temporarily (Wardle et a/. 1995). A comparison of nodding thistle biology to another weed, diffuse knapweed, Centaurea diffusa Lam. and Frauenfeld (Asterales, Asteraceae), may indicate why a seed feeder is successful for nodding thistle but not for more typical weeds that are longer lived and better competitors. Knapweed is a short-lived (2-5 years) perennial and is able to invade sites that have experienced little disturbance (Berube and Myers 1982). Knapweed has very high summer survival of the rosette stage (90-95%) while rosette survival of nodding thistle can be low (10-30%) (Sheppard et a/. 1994). A simulation model of knapweed population growth indicated that because seedling survival was

73 density dependent, the only way to reduce weed density would be via an agent that killed rosettes (Myers and Risley 2000). Similarly, Kelly and McCallum (1995) found that density-dependent survival from seedling to flowering in nodding thistle plants compensated for seed loss, the higher mortality among rosettes in nodding thistle may mean that reduced seed production is sometimes translated into reduced plant density. Although seed predators may be effective in reducing the density of annual plants that are poor competitors, most invasive weeds are longer-lived and good competitors. Seed predators may be attractive as biological control agents because they are relatively easy to find, particularly if they develop in the seed heads. Also, biological control success is often measured simply by the number of plants attacked rather than impacts on plant density (McFadyen 2000). This also makes seed predators attractive as candidates for biological control programs because they can be readily evaluated. The over-use of seed predators is demonstrated in the biological control program targeted against the yellow star thistle, Centaurea solstitialis L. Six species of seed predators have been introduced to North America against this weed (Pitcairn et a/. 1999). Although at some sites seed and seedling density have been reduced for several years, no reduction of plant density has been reported for this annual plant. Would one species of seed predator have been as effective as 6? Predicting the type of an agent that will be successful in reducing the dens~ty of a target weed is difficult. Study of the biology of the target plant may give some clues to "weak" points in the life cycle. If a plant produces lots of seeds it is unlikely that reduction in seed production will be translated to a reduction of plant density. Experiments in which the ability of plants to compensate for various types of damage may give clues of the type of agents that are likely to be effective. In addition, Force (1972) and Zwolfer (1973) have proposed that the most effective biological control agents are likely to be those that are not very common in the native distribution of the plant. If a species of natural enemy occurs at low density in the native habitat because it is a poor competitor or has a hlgh level of parasitism it may demonstrate a good reproductive response when introduced to a new habitat, free of competitors and parasitoids. Therefore, being rare in the native habitat and having a high reproductive rate when reared In the absence of natural enemies or competitors may be characteristics to look for in potential biological control agents. Because the introduction of non-indigenous species dilutes the native biodiversity of an area, the introduction of new species should be undertaken in a conservative manner. Just because a species has passed the host specificity tests does not necessarily mean it should be introduced. The possibility of non-target impacts should always be a concern. Therefore, efficacy should be another consideration iehoosing potential biological control agents. A study of the biology of the target weed, including its ability to compensate for the loss of various life stages, should be a prerequisite for biological control introductions. A good example of compensation for herbivory is shown by lantana, Lantana camara L. (Lamiales, Verbenaceae), which survived experimental defoliation for 2 years (Broughton 2000). Defoliators are unlikely candidates to successfully control this plant species. Prediction of the impact of natural enemies on host plant density is certainly not easy. One way to evaluate control agents may be to create high-density patches in the native habitat and determine which species of natural enemies move onto the plants. By evaluating the impacts of potential agents in the native habitat, informed decisions can be made prior to introduction in the new habitat. Better evaluation of on going biological control programs could also provide information to allow improved understanding of what

74 things work and why. From current information, seed predators do not appear to be effective agents. Therefore their further introduction in biological control programs is unlikely to be a parsimonious approach to biological weed control. CONCLUSION By far the best approach to limiting potentially invasive weeds is limiting the introduction of plants to new areas. Better communication of the consequences and environmental costs of non-indigenous species may help balance the pressure applied on regulatory agencies by industries involved in commercial plant importations. Eradication attempts must be bold and fast. But because eradication is so difficult to achieve, proponents of the program should not make unrealistic promises. Finally, biological control does have potential for controlling the impact of foreign weeds. However, finding agents that are capable of reducing the densities of plants is not an easy task. Successful biological control is associated with agents that are capable of killing or greatly reducing the vigor of their host plants at a life stage for which little compensation can occur. A greater focus on the efficacy of proposed agents can help reduce the number of nonindigenous species that are introduced in biological control programs. ACKNOWLEDGEMENTS JHM wishes to thank the U.S. Forest Service, USDA for providing support to attend the Hawai'i Conservation Forum on Biological Control of lnvasive Plants in Hawaiian Natural Ecosystems. LITERATURE CITED Andersen, A How important is seed predation to recruitment in stable populations of long-lived perennials? Oecologia 81 : Andres, L., and E. Coombs Scotch Broom Cytisus scoparius (L.) Link (Leg uminosae). pp , In: Biological Control in the U. S. Western Region: Accomplishments and Benefits of Regional Research Project W-84 ( ). J. Nechols, L. Andres, J. Beardsley, R. Goeden and C. Jackson (Eds). Division+f-&6risultur~ftdNat racresourcemive~it-~f-califomia,berkeley, CA. -- Berube, D., and J. Myers Suppression of knapweed invasion by crested wheat grass in the dry interior of British Columbia. Journal of Range Management 35: Broughton, S Review and evaluation of lantana biocontrol programs. Biological Control 17: Clark, J., C., Fastie, G. Hurtt, S. Jackson, C. Johnson, G. L. King, M., and J. Lynch Reid's paradox of rapid plant migration. BioScience 48:

75 ~ - Cory, J., and J. Myers Direct and indirect ecological effects of biological control. Trends Ecology and Evolution 1 5: Crawley, M Insect herbivores and plant population dynamics. Annual Review of Entomology 34: Denoth, M., L. Frid, and J. H. Myers Multiple agents in biological control: Improving the odds? Biological Control (In Press). Follett, P.A. and J.J. Lynch. (eds.) Nontarget Effects of Biological Control. Kluwer Academic Publishers, The Netherlands Force D.C r- and K- strategists in endemic host-parasitoid communities. Bulletin, Entomological Society of America 1 8: Harris, P Carduus nutans L., nodding thistle and C. acanthoides L., plumeless thistle (Compositae). pp , In: Biological Control Programs Against Insects and Weeds in Canada J. Kelleher and M. Hulme (Eds). Commonwealth Agricultural Bureau, Slough, U.K. Hazard, W Introducing crop, pasture and ornamental species into Australia - the risk of introducing new weeds. Australian Plant Introduction Review 19: Impson, F., V. Moran, and J. Hoffman A review of the effectiveness of seedfeeding bruchid beetles in the biological control of mesquite, Prosopis species (Fabaceae), in South Africa. pp , In: Biological Control of Weeds in South Africa ( ). T. Olckers and M. Hill, (Eds). Entomological Society of Southern Africa, Johannesburg, SA. J ulien, M., and M. Griffiths Biological control of weeds: a world catalogue of agents and their target weeds. CAB International: Wallingford, Oxon. Kelly, D., and K. McCallum Evaluating the impact of Rhinocyllus conicus on Carduus nutans in New Zealand. pp , In: Vlll International Symposium ansio/o~e~~1~~fweeds~e;-delfosse-a~m~s~~~ed~si RO, Melbourne, Australia, Canterbury, New Zealand. Kok, L., and W. Surles Successful biological control of musk thistle by an introduced weevil, Rhinocyllus conicus. Environmental Entomology 4: Mot, M., M. Lewis, and P. van den Driessche Dispersal data and the spread of invading organisms. Ecology 77: Landolt, E ~ber Pflanzenarten, die sich in den letzten 150 Jahren in der Stadt Ziirich stark ausgebreitet haben. Phytocoenologia 23: Louda, S. 1982a. Limitation of the recruitment of the shrub Haplopappus squarrosus

76 (Asteraceae) by flower- and seed-feeding insects. Journal of Ecology 70: Louda, S. 1982b. Distribution ecology: variation in plant recruitment over a gradient in relation to insect seed predation. Ecological Monogmphs 52: Louda, S Seed predation and seedling mortality in the recruitment of a shrub, Haplopappus venetus (Asteraceae) along a climatic gradient. Ecology 64: Louda, S Population growth of Rhinocyllus conicus (Coleoptera: Curculionidae) on two species of native thistles in prairie. Environmental Entomology 27: Louda, S. M Negative ecological effects of the musk thistle biocontrol agent, Rhinocyllus conicus Foel. pp , In: Nontarget Effects of Biolo~ical Control. P. A. Follett and J. J. Duan, (Eds). Kluwer Academic Publishers, The Netherlands. Louda, S., and Potvin, M Effect of inflorescence-feeding insects on the demography and lifetime fitness of a native plant. Ecology 76: Louda, S., D. Kendall, J. Connor, and D. Simberloff Ecological effects of an insect introduced for the biological control of weeds. Science 277: Mack, R., D. Simberloff, W. Lonsdale, H. Evans, M. Clout, and F. Bazzaz Biotic invasions: causes, epidemiology, global consequences, and control. Ecological Applications 1 0: McFadyen, R. E Biological control of weeds. Annual Review of Entomology 43: McFadyen, R.E Successes in biological control of weeds. pp. 3-14, In: Proceedings X International Symposium Biological Control of Weeds. N. Spencer, (Ed). Montana State University, Bozeman, MO. Moody, M., and R. Mack Controlling the spread of plant invasions: the importance of nascent foci. Journal of Applied Ecology 25: Myers, J How many insect species are necessary for successful biocontrol of weeds? pp , In: Proceedings VI. International Symposium on Biological Control of Weeds. E. Delfosse, (Eds). Agriculture Canada, Ottawa. Myers, J., and C. Risley Why reduced seed production is not necessarily translated into successful biological weed control. pp , In: Proceedings X International Symposium Biological Control of Weeds. N. Spencer, (ed). Montana State University, Bozeman, MO.

77 Myers, J., C. Risley, and R. Eng The ability of plants to compensate for insect attack: Why biological control of weeds with insects is so difficult. pp , In: VII. International Symposium on Biological Control of Weeds. E. Delfosse (Ed). lnstituto Sperimentale per la Patologia Vegetale, Rome Italy. Myers, J., D. Simberloff, A. Kuris, and J. Carey Eradication Revisited: dealing with exotics. Trends in Ecology and Evolution 15: Olckers, T., and M. Hill Biological Control of Weeds in South Africa ( ). African Entomology Memoir No.1. Entomological Society of Southern Africa: Johannesburg, SA. Panetta, F A system for assessing proposed plant introductions for weed potential. Plant Protection Quarterly 8: Parker, I.M Invasion dynamics of Cystisus scopan'us: a matrix model approach. Ecological Applications 10: Pemberton, R. W Cactoblastis cactorum (Lepidoptera: Pyralidae) in the United States: An immigrant biological control agent or an introduction of the nursery industry? American Entomologist 41 : Pheloung, P Determining weed potential of new plant introductions to Australia. A report on the development of a weed risk assessment system commissioned and endorsed by the Australian Weeds Committee and the Plant Industries Committee. Agricultural Protection Board, Western Australia. Pitcairn, M., D. Woods, D. Joley, C. Turner and J. Balciunas Population buildup and combined impact of introduced insects of yellow starthistle, Centaurea solstitialis, in California. pp , In: X Symposium, Biological Control of Weeds. N. Spencer (ed). Bozeman, MO. Reichard, S., and F. Campbell Invited but unwanted. American Nurseryman 187: Reichard,~.,and-C,HmiIton.~l996.~Predicting-invasionsoffwoOoOdy_plantsintc~duced~_~ into North America. Conservation Biology 11: Sheppard, A., J. Cullen, and J. Aeschlimann Predispersal seed predation on Carduus nutans (Asteraceae) in southern Europe. Acta Oecologica 15: Silverton, J., and J. Lovette-Doust Introduction to pbnt population biology. Blackwell Scientific Publications, Oxford. Wardle, D., K. Nicholson, M. Ahmed, and A. Rahman Influence of pasture forage species on seedling emergence, growth and development of Carduus nutans. Journal of Applied Ecology 32:

78 White, P., and A. Schwarz Where do we go from here: the challenges of risk assessment for invasive plants. Weed Technology 12: Zwolfer, H Competition and coexistence in phytophgagous insects attacking the heads of Carduus nutans L. pp , In: I1 International Symposium, Biological Control of Weeds. P. H. Dunn (ed). Rome, Italy.

79 HOST SPECIFICITY TESTING FOR ENCARSIA SPP., PARASlTOlDS OF THE SILVERLEAF WHITEFLY, BEMISIA ARGENTIFOLII BELLOWS & PERRING, IN HAWAI'I Walter T. Nagamine and Mohsen M. Ramadan Hawai'i Department of Agriculture, Biological Control Section, 1428 South King Street, Honolulu, Hawai'i 96814, U.S.A. Walter- T- Nagamineaexec. state. hi. us ABSTRACT. We describe host specificity studies for four Encarsia spp. (Hymenoptera: Aphelinidae) parasitoids used in the biological control of the silverleaf whitefly, Bomisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae), in Hawai'i. The problems encountered in determining rion-target test species are described with respect to the potential impact on Hawaiian Lepidoptera. The misidentification of an Encarsia sp. in the scientific literature suggested that one of the four Encarsia spp. parasitoids would parasitize lepidopteran eggs. This information created confusion and cast doubt on our test results. An authority on Encarsia parasitoids re-examined the misidentified species and corrected its identity. Key words: Aleyrodidae, Aphelinidae, Bemisia, biological control, Encarsia, host specificity tests, lepidopterous eggs, non-target species, silverleaf whitefly The silverleaf whitefly, Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae), is a major pest of many vegetable crops in Hawai'i. In 1992, the Hawai'i Department of Agriculture began a biological control program for the silverleaf whitefly. Some species of Encarsia (Hymenoptera: Aphelinidae) are well known as biological control agents of whiteflies and other Homoptera and are generally host specific. The department's exploratory entomologist collected four species of Encarsla parasitoids; E. lutea (Masi) and E. mineoi Viggiani from Egypt in 1992, and E. hispida DeSantis and E. pergandiella Howard from Brazil in There is an increasing awareness and concern regarding the potential of biological control agents to attack non-target hosts (Howarth 1991). In Hawai'i, host specificity studies usually require testing of non-target species. Since all whitefly species in Hawai'i are immigrants (there are no natives or beneficial species), testing was not considered necessary as long as the potential agent was known to be specific in host selection. It0~e~~r;-E~~arSia~1u~-h-ad-b8~m~~san~ag~ar~t0id~+thet,~Ifw Heliothis zea (Boddie) (Lepidoptera, Noctuidae) and the cabbage looper, Trichoplusia ni (Hubner) (Lepidoptera, Noctuidae) in Arizona cotton fields (Stoner and Butler 1965). Female parasitoids emerged from whiteflies, while male parasitoids emerged from the moth eggs. Egg parasitism in this genus is not as rare as had been thought. Polaszek (1991) summarized lepidopteran egg hosts of Encarsia and found records of 18 species of Lepidoptera from six different families that were parasitized by Encarsia. Encarsia and other genera in the family Aphelinidae have complex natural histories in which males and females of the same species have different host relationships (Walter 1983). In some Encarsia species, females will develop almost always as primary parasitoids of whitefly hosts. Males, however, can develop in one of three ways:

80 1. as primary parasitoids of whitefly hosts; 2, as hyperparasitoids, developing at the expense of female larvae or pupae of their own species, other primary parasitoid species, or both; and, 3. as primary parasitoids of lepidopteran eggs. The potential non-target host species included exotic, beneficial, and native species. We conducted tests to determine if the presumed E. lutea from Egypt would parasitize lepidopteran eggs to produce male parasitoids as the E. lutea from Arizona was reported to do. The four species of Lepidoptera used were the cabbage looper, Trichoplusia ni (Hubner); tobacco budworm, Heliothis virescens (Fabricius); tomato pinworm, Keiferia lycopsersicella (Walsingham) (Lepidoptera, Gelichiidae); and diamondback moth, Plutella xylostella (L.) (Lepidoptera, Plutellidae). Our results showed that the Egyptian strain of E. /utea did not parasitize the eggs of any of the Lepidopteran species tested, raising the question of why the Arizona strain but not the Egyptian strain was able to parasitize lepidopteran eggs. Further examination of the voucher specimens from the 1965 Arizona study found that this Encarsia sp. had been misidentified; it was not E. lutea, but an undescribed species (Williams and Polaszek 1996). Excellent taxonomic work and related studies resolved the dilemma and cleared E. lutea as a parasitoid of potential harm to Hawaiian Lepidoptera. LITERATURE CITED Howarth, F.G Environmental impacts of classical biological control. Annual Review of Entomology 36: Polaszek, A Egg parasitism in Aphelinidae (Hymenoptera: Chalcidoidea) with special reference to Centrodora and Encarsia species. Bulletin of Entomological Research 81 : Stoner, A. and G.D. Butler Encarsia lutea as an egg parasite of bollworm and cabbage looper in Arizona cotton. Journal of Economic Entomology 58: Walter, G.H Divergent male ontogenies in Aphelinidae (Hymenoptera: Chalcidoidea): a simplfied classification and a suggested evolutionary sequence. Biological Journal of the Linnaean Society 19: Williams, T. and A. Polaszek A re-examination of host relations in the Aphelinidae (Hymenoptera: Chalcidoidea). Biological Journal of the Linnaean Society 57:

81 PREDICTABLE RISK TO NATIVE PLANTS IN BIOLOGICAL CONTROL OF WEEDS IN HAWAI'I. Robert W. Pemberton lnvasive Plant Research Lab, USDA-Agricultural Research Service 3205 College Ave. Ft. Lauderdale, FL 33314, U.S.A. ABSTRACT. The analysis examines the use of non-target native plants in Hawai'i resulting from biological control projects on target weeds with close relatives compared with projects on target weeds that lack close relatives. Target weeds with close relatives are riskier targets for biological control than are weeds without close relatives in Hawai'i. The two projects conducted against weeds with close relatives resulted in non-target use of native species; four of the five insect species established in these projects now use native plant species as hosts. Only one of 18 (5.0%) projects against Hawaiian weeds that lack close relatives has produced native plant use. Overall, 53 of 54 agents established for weed control exhibit predictable and highly stable host ranges. This pattern of non-target plant use indicates that the risk to the native flora can be judged reliably before introduction. The degree of risk is directly related to the relative relatedness of the targeted Weeds and the natlve flora and the speclflcity or the natural enemies employed. Keywords: biological control of weeds, non-target use, insectlplant interactions INTRODUCTION Biological control is a valuable method of controlling introduced pests in agriculture and in natural areas. Biological control is currently being employed against invasive weeds at a number of United Nations World Heritage Sites including South African Cape Fynbos, Kakadu National Park in northern Australia, and Everglades National Park in Florida (Center 1995). It has been an important tool in the fight against introduced weeds in Hawai'i for almost 100 years (Funasaki et a/. 1988). Like other pest control technologies it carries some risk. The associated risks relate primarily to organisms targeted for biological control and host specificities of the biological control agents employed. The safety of introduced biological control organisms to non-target native organisms is an important issue in biological control (Follet & Duan 2000, Wajnberg 2001). In the 1980's some practitioners of biological control of weeds reported the use of native plants by introduced biologicalx6ittrol agen6 (Andres 1985, Pemberton 1985, Turner 1985, Turner et a/. 1987). Howarth (1983,1991) challenged the safety of biological control in general and specifically in Hawai'i, claiming harm to native insects by introduced biological control parasitoids. Hawkins and Marino (1997) examined the use of North American native insects by introduced parasitoids and found that 16% of these parasitoids adopted native insects as hosts. Louda etal. (1997) reported population level damage to a native Cirsium thistle in Nebraska by the biological control weevil Rhinocyllus conicus (Froelich) (Coleoptera, Curculionidae). Because of the concerns for and documented cases of non-target impacts, reform of biolo~ical control practice and regulation to ensure greater attention to environmental safety is needed (McEvoy and Coombs 2000, Strong and Pemberton 2000). An important part of the biological control safety debate concerns the predictability and stability of the host ranges of introduced biological control agents. Understanding the predictability and stability of the host ranges of introduced agents is hampered by the

82 lack of general assessments of non-target host usage. This paper draws upon my recent analysis of the use of non-target native plants by introduced biological control agents of weeds in the United States, the Caribbean, and Hawai'i (Pemberton 2000). Presented here is the information for Hawai'i. MATERIALS AND METHODS The analysis examines the use of non-target native plants in Hawai'i resulting from biological control projects on target weeds with close relatives compared with projects on target weeds that lack close relatives. By "use" I mean a completed life cycle of the introduced agent on the non-target plant species. "Use" does not imply impact that is unstudied. Close relatives are defined as congeneric species in the native flora. The data set includes the establishment of 54 agents on 20 target weeds in Hawai'i. The first releases were against Lantana camara L. (Lamiales, Verbenaceae) in The last introductions resulting in establishment included in the analysis were in 1994; later releases were excluded because I judged that insufficient time had passed for agent population growth and dispersal to non-target species. Overall agents established on weeds with close relatives and on weeds without close relatives have been released for similar mean lengths of time (47 vs. 50 years, respectively). The source of information on biological control of weeds projects in Hawai'i is Julien and Griffiths' Bioiogical Control of Weeds: A World Catalogue of Agents and Tk)eir Target Weeds. The principal source of information on the use of non-target native plants is the entomological literature supplemented with personal communications with researchers familiar with the projects. RESULTS AND DISCUSSION Target weeds with close relatives are riskier targets for biological control than are weeds without close relatives in Hawai'i. The two projects conducted against weeds with close relatives resulted in non-target use of native species; four of the five insect species established as biological control agents in these projects now use native plant species as hosts (Tables 1, 2). The project to control an introduced blackberry, Rubus argutus Link - Rosales, Rosaceae) led to the establishment of three insect species in the 1960's; all three use the two native Hawaiian species, Rubus hawaiensis A. Gray and R. macraei A. Gray, (Funasaki et a/. 1988, George Markin, personal communication). The other project in this category, control purple nutsedge, Cyperus rotundus L. - Juncales, Cyperaceae, established two insect species, one of these, a weevil (Athesapeuta cyperi ~ ~ l ~ ~ e r a, ~ ~ ~ l i ~ m 5 d a ~ ) ~ i n t r b d ~ ~ ~ ~ 1 n ~ ~ s ~ ~ s 3 - ~ ~ a polystachyos Rottb. (Poinar 1964). By comparison, only 1 of the 18 (5.6%) projects against Hawaiian weeds that lack close relatives has produced native plant use (Tables 1, 2). In these projects, only 1 of 49 (1.6%) established biological control agents now uses a native Hawaiian host. The lacebug Teleonemia scrupulosa Stal (Hemiptera,Tingidae), introduced for control of Lantana camara L. (Lamiales, Verbenaceae), was reported to use naio, Myoporum sandwicense (DC) Gray (Lamiales, Myoporaceae), an endemic shrub (Maehler and Ford 1955, Bianchi 1961). All five biological control insects that have adopted native nontarget plants as hosts were released prior to 1970, before risk to native plants was seriously considered by Hawaiian biological control researchers (Ken Terrarnoto, personal communication). In Hawaiian biological control projects, 53 of 54 established agents exhibit predictable and highly stable host ranges.

83 Teleonemia scmpulosa was collected in Mexico and released in Hawai'i in 1902, without host specificity testing. The insect has been thought to be a Lantana specialist (Winder and Harley 1983). The Myoporaceae and Verbenaceae are now considered to be in the same order- the Lamiales (Angiosperm Working Group 1998), but lantana and naio are not closely related. Changes in our understanding of plant phylogenetic relationships brought about by molecular research (e.g., DNA sequence data: Angiosperm Worklng Group 1998) suggest that ~twlll be Important to evaluate the weed and its relatedness to the Hawaiian flora in this light. The true host range of T. scrupulosa is unclear. When introduced to Uganda for lantana control, it fed on and damaged sesame, Sesamum indicum L. - Lamiales, Pedaliaceae), and reproduced on the plant to a limited extent (Davies & Greathead 1967). This report, as well as other unverified records on target hosts (a Lippia sp. - Verbenaceae) in the Antilles, ebony, Diospyms sp. - Ebenales, Ebenaceae) in the U.S. (Drake and Ruhoff 1965), and Xanthium sp. (Asterales, Asteraceae) in Hawai'i (Funasaki et a/. 1988), suggest that the insect may not be the specialist that it was presumed to be. Recent searches on the island of Hawai'i, where both naio and lantana grow closely together, found much T, scrupulosa damage to lantana but none to naio (S. Hight and P. Conant, personal communication). This pattern of non-target plant use by introduced biological control agents indicates that the risk to the native flora can be judged reliably before introduction. The degree of risk is directly related to the relative relatedness of the targeted weed and the species in the native flora. Species in the native flora can be protected by selecting target weeds that are related only distantly to species in the flora and by employing agents with diets narrow enough to avoid damaging native plants in the flora. Hawai'i's flora is taxonomically circumscribed, with many common plant families absent or with limited distribution (Wagner et a/. 1999). Most invasive weeds are distantly related to native species, which suggests that biological control programs against these weeds would unlikely harm native species. Of the 20 targeted weeds for which biological control agents were released prior to 1994, only two have close relatives. These weeds were targeted because of the problems they caused, independent of the presence of native relatives. The Hawai'i Department of Agriculture's Priority lists of weeds for FY 2000 (Nakahara 1999) lists 30 plant species for which chemical/mechanical or biological control activities will be directed. Seven of these plants belong to non-native families, while 17 others belong to non-native genera (Wagner et al. 1999). Only six of these plants have congeneric native relatives that could be put at risk by biological control. These are species of Acacia, Caesalpinia, Cenchrus, Rubus, Solanum, and possibly Digitaria (one species may be native) (Wagner et a/. 1999). Most of the seriously disruptive weeds in Hawai'i lack close relatives in the native flora. For instance, Hawai'i has many invasive weeds in the Melastomataceae, including the dangerous Miconie celvescens DC (Myrtales, Melastomataceae) (Medeiros et a/. 1997) but no native members of this family. Similarly, Hawai'i has no native gingers (Zingiberales, Zingiberaceae) so biological control of Kahili ginger (Hedychium gardnerianum Sheppard ex Ker-Gawl.), which can dominate the understory of rain forests at mid-elevations, should be of low risk to the native flora. However, cultivated gingers in Hawai'i are closely related and must be considered. Although this paper deals with the risk to native plants, risk to other valued plants (agricultural, horticultural, and cultural) related to the target weed also should be considered, as they traditionally have been. Likewise, the lack of native species of Psidium, Senecio, and Paederia suggest that weeds in these genera are appropriate targets. Since all three genera belong to families containing native plants, it is important to evaluate the degree of

84 relatedness of the weeds to their confamilial Hawaiian relatives. lnvasive weeds with close relatives, such as Himalayan blackberry (Rubus ellipitcus Sm.), would be much riskier targets for biological control. Specialist insects typically use host plants limited to a circumscribed taxonomic range (Strong et a/. 1984), e.g., within a plant family, within a tribe within a family, a genus, subgenus, section or even a species. However, single species specificity is less common than genus or subgenus host specificity). Plant pathogens may have narrower host plant ranges than insects, w~th some forms llm~ted to subspecific taxa of plants, as with the rust Puccinia chondriilina Bubak & Snow (Uredinales, Pucciniaceae) used to control rush skeletonweed, Chondrilla juncea L.in California (Plper and Andres 1995). Careful determinatlon of field host range of the candidate biological control organism in its native area coupled with rigorous host plant specificity testing will predict the agent's potential host range in the area of introduction. The specificity requlred depends directly on the degree of relatedness of the target weed and species in the local native flora (Pemberton 2000). Biological control agents employed against melastomaceous weeds in Hawai'i need be tested against native species only at the family level to assess their likely use of native species. By contrast, agents employed against Rubus weeds should be tested against individual species of Rubus to avoid introducing species that might feed on Hawai'i's two native Rubus species. The natural enemy pool from which to select biological control agents will be larger for potential agents that require testing only at the family level. Species level specialists, which may be needed for weeds with congeneric native relatives, may not exist or may be difficult to find. Moreover, projects on weeds with close relatives will be more expensive because more exploration and host specificity testing will be needed to identify narrower specialists. Given enough resources and time to identify specialist enemies and to confirm their specificities, projects on weeds with close relatives can still be viable. The biological control effort against leafy spurge (Euphorbia esula L.) in North America is an example of a successful program on a weed with many native relatives in North America (Nowerski and Pernberton, in press). This program was successful despite the many native Euphorbia species in North America for a number of reasons. First, most of the native species were actually not very closely related the target weed; most belong to subgenera other than the subgenus Esula to which the target weed belongs. Second, funding for the primary research programs continued for more than 25 years, which enabled the examination of large numbers of candidate agents. This enabled the narrow specialists to be identified and employed and the candidates with broader host ranges to be discarded. Third, large numbers of narrow specialists that are also very damaging to target weed, the Aphthona flea beetles (Erysomelidae), had evolved with subgenus Esula plants. Given the constraints on funding for biological control, the limited quarantine space and low number of qualified biological control researchers, only a small portion of invasive weeds can be subject to full biological control programs. Potential targets are then necessarily prioritized by the seriousness of the problems they cause (kinds of impacts, rates of spread, etc.), the control potential and cost of biological control, and risk associated with such projects. Weeds with close relatives reasonably should be of lower priority. Because biological control can be so effective against invasive weeds that are frequently difficult to manage by other methods, there is a tendency to view all such weeds as appropriate targets. But biological control may not be the most appropriate control method for weeds with close native relatives. The risk to native plants associated with biological control projects on weeds with close relatives should be considered in relation to the risks associated with other control methods or with the continued spread of the weed. In the fight against aggressive invasive weeds, absence

85 of control is not without risk as well. Fortunately, most Hawaiian weeds appear to be safe targets for biological control. ACKNOWLEDGEMENTS I thank Pat Conant and Ken Teramoto (Hawai'i Department of Agriculture), and Frank Howarth (Bishop Museum) for help with Hawaiian literature. Stephen Hight (US Forest Service) and Pat Conant kindly shared their field observations of Telelonemia scrupulosa damage to Lantana camara but not to Myopomm sandwicense. I am particularly grateful to George Markin (US Forest Service) for allowing me to use his unpublished observations of the use of native use of native Hawaiian Rubus by ~ntroduced biological control agents. LITERATURE CITED Andres, L. A Interaction of Chrysolina quadrigemina and Hypericum spp. in California. pp In: E. S. Delfosse (ed), Proceedings, VI International Symposium Biological Control of Weeds. Agriculture Canada. Angiosperm Working Group An ordinal classification for the families of flowering plants. Annals Missouri Botanical Garden 85: Bianchi, F Teleonemia scrupulosa. Proceedings, Hawaiian Entomological Society 17: 313. Center, T. D Selection criteria and ecological consequences of importing natural enemies. Biodiversity and Conservation 4: Davies J. C. and Greathead, D. J Occurrence of Teleonemia scrupulosa on Sesamum indicum Linn. in Uganda. Nature 230: Drake, C. J. and Ruhoff, F. A Lacebugs of the world. Bulletin U. S. National Museum 243: 384. Follet, P. A. and Duan, J. J. (eds.) Non-Target Effects of Biological Control. Kluwer, Dordrecht, The Netherlands. Funasaki, G.Y., Lai, P-Y., Nakahara, L.M., Beardsley, J., and Ota, A. K A review of biological control introductions in Hawaii: Proceedings, Hawaiian Entomological Society 28: Hawkins, B. A., and Marino, P.C The colonization of native phytophagous insects in North America by exotic parasitoids. Oecologia 112: Howarth, F. G Biological control: panacea or Pandora's box? Proceedings, Hawaiian Entomological Society 24: Howarth, F. G Environmental impacts of classical biological control. Annual Review Entomology 36:

86 Julien, M. H. and Grlfflths, M. W. (eds.) Biological Control of Weeds; A World Catalogue of Agents and Their Target Weeds. Edition 4. C.A.B. International, Wallingford, UK. Louda, S. M., Kendall, D., Connor, J., and Simberloff, D Ecological effects of an insect introduced for the biological control of weeds. Science 277: McEvoy, P. B, and Combs, E. M Host specificity and biological pest control. pp In: P. A. Follet and J. J. Duan (eds), Nontarget Effects of Biological Control. ( Kluwer, Dordrecht, The Netherlands. Maehler, Mr., and Ford, Mr Teleonemia scnrpulosa. Proceedings, Hawaiian Entomological Society 15: 377. Medeiros, A.C., Loope, L. L., and Conant, P Status, ecology, and management of the invasive plant, Miconia calvescens DC (Melastomataceae) in the Hawaiian Islands. Bishop Museum Occasional Papers 48: Nakahara, L Priority lists of weeds for FY (unpublished memorandum, Nov. 16). Hawai'i Department of Agriculture. Nowierski, R.M. and R.W. Pemberton. Leafy spurge (Euphorbia esula L.). In: R. Van Driesche, B. Blossey and M. Hoddle, S. Lyon and R. Reardon (eds.) Biological control of invasive plants in the eastern United States. US Forest Service Forest Health Technology Enterprise Team , Morgantown, West Virginia. (in press) Pemberton, R. W Native plant considerations in the biological control of leafy spurge. pp In, E. S. Delfosse (ed), Proceedings VI lntemational Symposlum Biological Control of Weeds. Agriculture Canada. Pemberton, R. W Predictable risk to native plants in weed biological control. Oecologia 125: Piper, G. L., and Andres, L. A Rush Skeletonweed. pp , In: J. R. Nechols, L. A. Andres, J. W. Beardsley, R. D. Goeden, and C. G. Jackson (eds), Biological control in the western United States. University of California Division of Agriculture and Natural Resources Publication 3361, Oakland, CA. Poinar, G. 0. Jr Observations on nutgrass insects in Hawaii with notes on the host range of Bactm tmculenta Meyrick and Athesapeuta cypen Marshall. Proceedings, Hawaiian Entomological Society 18: Strong, D. R., Lawton, J. H., and Southwood, R Insects on Plants. Harvard Univ. Press, Cambridge. Strong, D. R., and Pemberton, R. W Biological control of invading species: risk and reform. Science 288: Turner, C. E Conflicting interests and biological control of weeds. pp In: E. S. Delfosse (ed), Proceedings VI lntemational Symposium Biological Control of Weeds. Agriculture Canada.

87 Turner, C. E., Pemberton, R. W., and Rosenthal, S. S Host utilization of native Cirsium thistles (Asteraceae) by the introduced weevil Rhinocyllus conicus (Coleoptera: Curculionidae) in California. Environmental Entomology 16: I 1 I Wagner, W. L., Herbst, D. R., and Sohmer, S. H Manual of Flowering Plants of Hawai'i Vol. 1 and 2. (revised edition). University Hawai'i Press and Bishop Museum Press, Honolulu. Wajnberg, E., Scott, J. K., and Quimby, P. C in press. Evaluating Indirect Ecological Effects of Biological Control. International Organizationation of Biological Control, Montpellier, France. Winder J. A. and Harley, K. S The phytophagous insects on Lantana in Brazil and their potential for biological control in Australla. Tropical Pest Management 29:

88

89 TABLE 2. Comparison of non-target use of native plants by introduced agents in biological control projects on target weeds with close relatives against projects on target weeds that lack close relatives. Close relatives are plant species that belong to the same genus as the weed. Target Weeds With native relatives Without native relatives Percent of projects with non-target 100 use Percent of agents adopting native 80.0 hosts Number non-target plants used Total agents 54 Percent using non-target native plants 9.3 Percent of unpredicted use 1.6

90 REVIEW AND PERMIT PROCESS FOR BIOLOGICAL CONTROL RELEASES IN HAWAI'I Neil J. Reimer Hawai'i Department of Agriculture, Plant Quarantine Branch, 701 llalo St., Honolulu, HI 96813, U.S.A. Emai I: hawaii. edu ABSTRACT. A review of the permitting process for the introduction of biological control agents into Hawai'i is presented. The effects and results of the permitting process on the screening and establishment of host specific biocontrol agents are discussed. Keywords: Biocontrol introductions, permit, host specificity INTRODUCTION Hawai'i has had a long history in the use of biological control to reduce population levels of introd!cced pests (Funasaki etal. 1988). The first use of classical biocontrol in Hawai'i was in 1893 by Albert Koebele, entomologist for the Republic of Hawai'i, against the cottony cushion scale (Icefya purchasi Maskell (Homoptera: Margarodidae) (Timberlake 1926). The project was successful and the reaction to subsequent pest problems in Hawai'i often has been the introduction of natural enemies of the pest (Table 1). Diverse fauna and flora have been used to combat equally diverse pests. Examples include insects, fungi, viruses, bacteria, snails, bats, birds, fish, toads, and frogs to control insects, plants, snails, and other organisms (Table 2). Many of these introductions appear to have been successful in that the pest populations eventually did drop to acceptable levels, although scientific evaluations of the effectiveness of these introductions have been virtually non-existent. The result of these introductions has been the establishment of 266 alien insect species. This is a small percentage (3%) of the total insect fauna of ca species (Nishida 1994)); however, some of these introductions have had dramatic effects on a few of the 5000 endemic species (Howarth 1985). These negative impacts of biocontrol introductions primarily have been due to the lack of pre-release risk analyses, poor to nonexistent host specificity studies, and the absence of adequate import regulations. The U. S. Department of Agriculture - Animal Plant Health Inspection Service - Plant Pest Quarantine (USDA-APHIS-PPQ) and the Hawai'i Department of Agriculture (HDOA) currently regulate the importation of biocontrol agents into Hawai'i. These two agencies have different jurisdictions and mandates, with some overlap. The USDA has statutory authority under the Plant Quarantine Act (1912), the Federal Plant Pest Act (1 957), and the Federal Noxious Weed Act (1 974) to prevent the introduction and dissemination of plant pests (7 CFR 371.(~)(2)) The USDA only has the authority to regulate an organism if it feeds on, infects, or parasitizes living plant tissue or plant products, transmits plant pathogens, attacks a natural enemy of an herbivore or plant pathogen, attacks pollinators, or attacks organisms that control weeds. The agency does not have the authority to regulate biocontrol agents that are not plant pests.

91 All biocontrol agents imported for weed control attack plants and are by definition plant pests. They are, therefore, regulated by USDA. The USDA requires separate permits for 1) Importation of a plant pest into the U.S.; 2) Movement of a plant pest between States; and 3) Release of a plant pest into the environment. The federal permitting process requires the submission of PPQ Form 526 (Application for Release) that is forwarded to the HDOA for review and recommendations. All applications to date, for which HDOA has recommended rejection, have also been denied by the USDA. If approval is recommended by HDOA, USDA then reviews the application. This process usually involves review by the Technical Advisory Group; however, Hawai'i applications are exempt from TAG review due to the thoroughness of the HDOA review process. A draft environmental assessment (EA) is requested from the applicant for any requests for the release of weed biocontrol agents. The USDA prepares the final EA. If endangered or threatened species potentially are affected by the release of a biocontrol agent then the application is sent to the U.S. Fish and Wildlife Service for review. A release permit is issued if the evaluation of the EA produces a finding of no significant impact (FONSI). The HDOA permitting system differs from the federal system, in part, because of fundamental differences in purpose as defined in the State statutes. In contrast to federal law, Chapter 150A of the Hawai'i Revised Statutes (HRS) regulates the importation of any plant or animal, regardless of whether or not it is a plant pest. The HRS addresses the importation of non-domestic animals (including reptiles, mammals, birds, arthropods, and mollusks), microorganisms, and plants. The HDOA permitting system was not designed specifically for the regulation of biocontrol agents, yet it does govern their importation and release. Specifically, the HRS prohibits the importation of all non-domestic animals and microorganisms urlless approved by the Board of Agriculture. The regulation of animal importations into Hawai'i has had a long history beginning in 1890 with the establishment of the "Laws of the Hawaiian Islands" by King David Kalakaua. This law included language to prevent the introduction of plants and animals that may become harmful to agriculture. Actual inspections of organisms proposed for importation were not conducted until 1902 and there were no official reviews of introductions between 1902 and In 1944, the Department of Agriculture and Forestry (now the HDOA) established a policy for Board of Agriculture (BOA) review of importation requests. This was followed in 1965 by a policy in which advisory ~s_ub~~ommi~~~~~~rnp~~ed of specialists reviewed the importation applications and - advised the BOA. In 1975, the HRS mandated that BOA review all importation applications; importation permits were based on the recommendations of a Plants and Animals Advisory Committee. This law was revised in 1990 to specify three lists of organisms to be reviewed prior to imponation. These were the Prohibited, Restricted, and Conditionally-Approved Lists. Organisms were not allowed to be imported into Hawai'i until they had undergone review and had been placed on one of these lists. Animals placed on the Prohibited List are nat allowed into the State under any conditions. Those on the Restricted List may be imported by government agencies, municipal zoos and aquariums under fairly restrictive conditions. Organisms on the Conditionally-Approved List may be imported by all of the above organizations and additionally by businesses and individuals under specific conditions. Biocontrol agents always have been placed on the Restricted List. As a result, only government agencies have been able to import biocontrol agents since the list was established in 1990 (Table 1). This may change in the near future. There are discussions currently underway to

92 place host-specific agents already established in Hawai'i on the Conditionally-Approved List. If approved, this modification would allow anyone to import and release these agents into Hawai'i. A major concern in relaxing importation restrictions on biocontrol agents is controlling the quality and purity of shipments aniving from insectaries on the mainland. Mechanisms should be developed for verification of the species identity of the biocontrol agents shipped and for determination of stock purity for each shipment. This may be accomplished through either an insectary certification process or an import inspection procedure. Table 1. lndlvlduals and Agencies Involved In the Introduction of blocontrol agents into Hawai'i. Year IndividuallAgency* ROH, sugar plantations, private individuals HSPA, TOH HDOA, HSPA HDOA, HSPA HDOA, PRI, USDA HDOA, PRI, UH, UC, USDA HDOA, HDOH HDOA H DOA HDOA, UH, USDA Forest Service HDOA, UH, USDA Forest Service Number of introductions HDOA = Hawai'i Department of Agriculture, HDOH = Hawai'i Department of Health, HSPA = Hawai'i Sugar Planters Association, PRI = Pineapple Research Institute, ROH = Republic of Hawai'i, TOH = Territory of Hawai'i, UC = University of California, USDA = United States Department of Agriculture. The review process for a State importation permit application involves 6 steps. - First, the application is submitted to the HDOA with all of required and pertinent information, including information on host specificity, distribution, preferred habitat, temperature requirements, etc. Host specificity studies may be carried out either in the country of origin or in one of the three approved containment facilities in Hawai'i. The Advisory Subcommittee then reviews the application. The recommendations from this subcommittee are passed on to the Plants and Animals Committee for their recommendations to the BOA. The BOA either approves or disapproves the application. If approved, the application is submitted to a public hearing process. Comments from the public are brought back to the BOA for discussion, followed by final approval or disapproval of the application. If approved, a State permit is issued. The organism may be imported and released if both State and Federal permits have been issued and permit conditions are met by the importers. The HDOA review process for the introduction of biocontrol agents has evolved into an effective system that screens agents for host specificity and potential negative

93 impacts on other species. None of the agents introduced since the review process was initiated in 1975 have attacked any native or beneficial plant or animal species. This was not the case for introductions before IMPORTATIONS A total of 708 natural enemies were released between 1890 and 1999, of which 286 have become established (Table 2). The majority (237) of these established agents have contributed to the control of the target pest species. However, 33 (1 3.6%) also attacked a different pest or native and/or beneficial non-target species. Native insects were attacked by 20 (8.2%) of these introduced biocontrol agents. Before 1944, the year that the BOA began reviewing the applications, only 54.7% of the introduced agents were host specific. Between 1944 and 1975 when the BOA reviewed all permit applications, the percentage of host-specific agents introduced increased to 77.4%. After 1975 host specificity for all released biocontrol agents was 100%; in that year the three committees (Entomology/Microorganism Subcommittee, Plants and Animals Committee, and BOA) began reviewing all applications. Table 2. Types of biological control agents introduced into Hawai'i between 1890 and 1999.

94 This change in the host specificity record likely is not due exclusively to changes in the regulatory process. Public attitude to environmental concerns has changed dramatically since the 1970's and this also may have strongly influenced decisions made by the review committees. Prior to the 1970Js, environmental impacts such as host specificity were of minor concern or of no concern to the BOA and subcommittees reviewing applications and were rarely if ever discussed. The Board focused on agricultural concerns almost exclusively. Environmental impacts and host specificity issues are now often the primary concerns addressed by these review committees. The current review process has been effective in limiting introductions to hostspecific biocontrol agents, but not very efficiently. The process can take from six months to one year after the application is received before a permit is issued. This delay is caused primarily by the requirement for a public hearing. The public hearing process currently Is changing to a public notification process for which public hearings on each island will no longer be required, an expensive and time-consuming process. Instead a call for comments from the public can be made by a notification in the Hawai'i newspapers. This change is expected to decrease the duration of the review process from one year to 3-4 months. The results will be the retention of the same high quality of application review and, hopefully, the continuation of the excellent record of 100% host specificity in biocontrol agents released since LITERATURE CITED Funasaki, G. Y., P-Y. Lai, L. M. Nakahara, J. W. Beardsley, and A. K. Ota A review of biological control introductions in Hawai'i: Proceedings Hawaiian Entomological Society 28: Howarth, F. G Impact of alien land arthropods and mollusks on native plants and animals in Hawai'i. pp , In Hawai'i's Ternstrial Ecosystems: Preservation and Management. C.P. Stone and J.M. Scott (Eds.). Cooperative National Park Resources Studies Unit, University of Hawai'i at Manoa. University of Hawai'i Press, Honolulu. iqishida, G. M Hawai'ian terrestrial arthropod checklist, Bishop Museum Technical Report No. 4. Timberlake, P. H Biological control of insect pests in the Hawai'ian Islands. Proceedings Hawaiian Entomological Society 6:

95 FOREST PEST BIOLOGICAL CONTROL PROGRAM IN HAWAI'I Clifford W. Smith Department of Botany, University of Hawai'i at Manoa, 3190 Maile Way, Honolulu HI 96822, U.S.A. Abstract. Forest weeds were not considered to be a major management problem in Hawai'i until the latter quarter of the last century. Most previous biological control programs in the state were against agricultural pests. An interagency committee (U.S.D.A. Forest Service, National Park Service, Hawai'i Department of Agriculture, Hawai'i Division of Forestry and Wildlife, and the University of Hawai'i) was established to encourage studies of forest pests, develop biological control agents and foster the implementation of their recommendations. The progress of biological control efforts against the following weeds in Hawai'i are presented: Ckdemia hirta, Hedychium gardnerianurn, Miconia calvescens, Myrica faya, Passiilora rnollissima, Psidium cattleianum, Rubus ellipticus, and Tibouchina herbacea. Recommendations are made for the establishment of oversight (action) committees for each targeted species, long-term commitment to a program once started, more thorough studies in the native range of the target species using local experts and students and a full-time advocate scientist for forest pest biological control in the Islands. Keywords: Clidemia hirta, Hedychium gardnerianum, Melastomataceae, Miconia calvescens, Myrica faya, Myrtaceae, Psidium caffleianum, Passiflora mollissima, Passifloraceae, Rosaceae, Rubus ellipticus Tibouchina herbacea, Zingiberaceae. INTRODUCTION Biological control has been an integral part of forest management in Hawai'i for 100 years. Forest weeds, however, were not considered to be a major management problem until the latter quarter of the last century. This indifference was in large part the result of the influence of Charles Lyon who had promoted the introduction of species to the Islands for watershed reforestation. Also, until quite recently, most naturalists were interested in native species, particularly the endemics. While they decried the weeds, they generally did little to control them even in the most critical areas let alone consider biological control as a management approach. In the early 1980's attitudes began to change. The National Environmental Protection Act required that federal agencies develop resource management plans for resources under their jurisdiction. This formalized planning and revlew process resulted in a professional transformation and expansion of the National Park Service (NPS) natural resources management program. Somewhat similar but less extensive modifications occurred in state programs. The state biological control program operated by the Hawai'i Department of Agriculture (HDOA) was willing to assist in the development of biological control agents for forest pests but only as an adjunct to their own mandates. In addition, their quarantine space was limited and located at sea level in Honolulu, unsuitable for species from high elevations the typical habitat of the forest weeds that were initially targeted. Forest managers also realized that a more focused program to promote development of biological control agents targeting forest weeds was needed. The issue came to a head during an annual performance review of NPS natural resource management programs and the Cooperative Pacific Science Unit by NPS Regional Chief Scientist Dennis Fenn in He requested that interested agencies meet to discuss the problem. Realizing that no single agency could support such a program on its own, five agencies committed

96 to cooperate in a forest pest management program that focused primarily on biological control. A Memorandum of Agreement was established between NPS, USDA Forest Service (USFS), Hawai'i Department of Agriculture (HDOA), Hawai'i Department of Land and Natural Resources (DLNR), and the University of Hawai'i (UH). The NPS agreed to convert one of their ree en houses at Hawaii Volcanoes National Park into a quarantine facility as well as provide a plant pathologist to work on the development of agents. The US Forest Service agreed to provide a biological control specialist to work on insects in the quarantine facility as well as act as the quarantine officer for the facility. HDOA was an important contributor because of its legislated mandate to oversee all biological control efforts in the state. DLNR proposed to lead the committee and fund programs. UH agreed to conduct research particularly on the post-release fate of agents through a monitoring program. All agencies agreed to fund biological research whenever possible. The Memorandum of Agreement was signed in Since then eight projects have come under the review and sponsorship of the Committee to varying degrees. They are summarized below. SPECIES TARGETED Clidemia - Clidemia hirta (L.) D. Don (Myrtales, Melastomataceae). See Conant (this volume). Clidemia is substantially controlled in open ranchland by the thrips, Liothrips urichi Karny (Thysanoptera, Phlaeothripidae). The leaf spot fungus (Colletotrichum gloeosporioides f. sp. clidemiae Trujillo Deuteromycotina, Melanconiaceae) has reduced some populations in rainforest areas. Clidemia is now spreading into lowland dry forest. Control is by no means complete and further agents are still needed for this species. As Conant (ibid) notes there are several potential insect agents. None, however, show much potential to control this weed. It may well be that there is no realistic hope to contain it in rainforest situations. The negative impact of this species needs to be reevaluated in light of recent introductions. It may be too early to tell if the seed predators are having any impact but Myers' (this volume) comments on their potential efficacy suggests that we should not expect any dramatic effects. Further studies should be conducted in Central America and directed at stem borers and defoliators. The studies should be long-term, conducted year-round, and focus on forested areas. - Banampoka - Passiflora mollissima (Kunth.) L.H. Bailey (Passifloraceae). This project has been led by DLNR since the early 1980's with considerable involvement of U.S.F.S. in the 1990's. Pemberton (1989) conducted the initial exploratory research in South America and noted that there was considerable potential to manage this species wlth biological control agents. Later exploratory research was focused in Colombia on his recommendation. However, the political instability of the region, a lack of leadership in the program and the absence of an oversight committee has hampered the project. The USFS sponsored research in Merida, Venezuela, for several years. The following insects have been studied and some released. Pyraustra perelegans Hampson (Lepidoptera: Pyralidae) feeds on leaves and buds. It has been released in 1801 with little effect. It is established on the Big Island but population levels are extremely variable. Most people assume that the insect was unable to overcome the many generalist lepidopteran parasitoids in the Islands. R. Leen (pers. comm.) suspects that a species of the fungus Metschnikowia (Ascomycete: Saccharomycetales) is responsible for the poor performance of the insect.

97 Unfortunately, no definitive study has been conducted to differentiate between these two hypotheses. However, other hypotheses need to be considered also, e.g., the climatic conditions are unsuitable. Unfortunately, the reason why a released insect does not live up to its potential is rarely studied formally. A few anecdotal notes are sometimes published. Cyanotrica necyria Felder (Lepidoptera Notodontidae), a leaf feeder from Ecuador and Colombia was released in It has established but has had no demonstrable effect. Further work on this species is desirable because it has a high potential completely defoliating plants. Josia fluonia Druce (Lepidoptera: Notodontidae), a defoliator, has been recommended for release but is awaiting final approval. One experiment suggested that it could complete its life cycle on apple but the few insects that did complete their life cycle were in very poor condition. Recent experiments have shown that it can survive on the edible passionfruit (P. edulis Sims f. flavicarpa Deg.) suggesting that the proposal for release should be reconsidered. Further work on this species is not recommended because the insect does not appear to have a significant impact on the target plant. Josia ligata Walker (Lepidoptera: Notodontidae), a defoliator, was brought into quarantine but the colony did not survive. Zapriotheca nr. nudiseta (Dlptera: Drosophilidae) larvae feed on flower buds. It has passed host specificity testing, but has not been proposed for release yet. This colony is certainly highly inbred. It appears to have considerable potential in disrupting the reproductive cycle of banana poka. Further importation of the insect is recommended to overcome genetic problems and enable host screening to be completed. It will be extremely difficult to assess the impact of this insect because large plants are needed. The logistics of handling such plants in quarantine are unrealistic and field studies in South America would be extremely difficult under current political conditions. A fungus, Septoria passiflorae Sydenham (Deuteromycetes, Dothidiaceae), was released 1006 and has had an apparently dramatic defoliating effect in Laupahoehoe, Hawai'i Island (D. E. Gardner, pers. comm.). Confirmation of the cause of defoliation is important in this case because previous defoliation events were attributed to drought conditions. Thorough evaluation of the effects of previous releases in the banana poka biological control program should be conducted before further work is considered. Species of Odonna (Lepidoptera, Oecoriphoridae), a root crown borer, and Dasyops (Diptera, Lonchaeidae), a stem borer, should be studied in South America to obtain data on life history, host specificity, and impact. The Dasyops has been brought into quarantine in Hawai'i where though the insects failed to mate they laid eggs profusely. -TheseinsectsaFekn~~htcrattackbana~apoka~~~r~etsidebemsefa~Mies-for handling them experimentally were not available at that time. Two other species are becoming serious weeds the sweet granadilla (P. ligularis Juss.) and yellow granadilla (P. laurifolia L.). Unlike the established melastomes, all of which can be targeted because the whole family is considered noxious, one member or the family, P. edulis, is a marginal agricultural crop. Many people, however, harvest it in the wild for desserts, jams, etc. P. mollisima is a species which ~llustrates the weakness of the recent approach to biological control against forest pests in the Islands. During the 's there was considerable enthusiasm for the establishment of a forest industry in the state. Banana poka was a threat to the prized koa timber market because it smothered the natural regeneration of the forest as well as damaging large trees due to the weight of the vines, especially when wet. When it was realized that large-scale forestry was unfeasible interest in forest problems declined and with it support to combat banana poka. It is still a serious problem in native forests on the Big Island and has also become established in

98 Kula, Maui. Other weeds, e.g., miconia, strawberry guava have supplanted interest and financial support for banana poka. The whole program is now in abeyance. Cooperation with similar control efforts in New Zealand is possible. Himalayan raspberry - Rubus ellipticus Sm. (Rosales, Rosaceae). A small cooperative exploratory program was established with the Chinese Academy of Agricultural Sciences Institute of Plant Protection, Beijing, In 1996 to look for diseases and insects that attack this species as well as R. niveus Thunb. in the Himalayan region of China. Earlier attempts in India to identify potential agents targeting this species failed due to various problems but particularly the remote locations of most known collection sites. No evaluation of potential agents in northern Thailand has been attempted. Attempts to establish a Rubus action committee have not been successful because nobody wants to lead it even though there is a strong interest to control the plant in the conservation, hunting and recreation communities. An action committee to coordinate the project, provide the necessary oversight and develop funding is necessary if this project is to move forward. The danger of non-target impacts is significant because of the coexistence of two native congeners, R, hawaiiensis Gray and R. rnacmei Gray. Previous agents introduced against R. argutus Link have attacked these species (Pemberton this volume) although with little apparent negative effect. Since no long-term monitoring was established when the insects were released, retrospective evaluation is virtually impossible. It is somewhat surprising that nobody has used the release of biological control agents to study the epidemiology of new arrivals in the Islands. Excellent opportunities for studying fundamental principles of island biology are being missed. Biological control is also without fundamental information that would probably enhance the success of future releases, particularly when so many previous releases failed. Fayatree - Myrica feya Ait. (Myricaceae). A previous attempt to control fayatree failed (Hodges & Gardner 1985). Eucosma smithiana (Walsingham) (Lepidoptera, Tortricidaae) was released in It is established on M. cerifera but not M. faya. The current project, coordinated by the Fayatree Action Committee, was led by the "Big Island Resource Conservation and Development Committee" in 1987, a local program of the USDA Soil Conservation Service (SCS), U.S. Department of Agriculture Resource Conservation and Develo~ment Aaencv - - on Hawai'i Island. The committee eventually stopped meeting in 1995'after many years of effective work soon after the RC&D lead person left the islands. Strong political support from E%g Island legislators continued funding through the Governor's Agricultural Coordinating Committee that was ultimately subordinated into the Hawai'i Department of Agriculture. Some of this funding was later reprogrammed into similar work on melastomes at the suggestion of agency personnel. Caloptilia nr. schinella (Lepidoptera, Gracillaridae) from the Azores and Madeira was released in It is established but has had no demonstrable effect. It is possible that leaf miner parasitoids may be attacking this moth (Conant, this volume). Cooperative programs with the University of the Azores failed to find any further suitable biological control agents for M. faya in its native range in the Azores or Madeira. Most insects found on fayatree had alternate hosts, such as Vaccinium, that made them unsuitable agents. A Septoria leaf spot fungus did cause premature leaf fall, but we were unable to obtain fertile material. A similar species, Septoria hodgesii Gardner (Deuteromycetes, Dothideaceae), from M. cerifera L. in the eastern US was released at

99 Volcano, Hawai'i Island in 1998, but with no noticeable impact to date. Trujillo (pers. comm.) has suggested that acid rain around the Volcano area inhibits spore germination, and that the fungus may be more successful if tested elsewhere. We have a single species in quarantine from Madeira, Phyllonorycter myricae Deschka (Lepidoptera, Gracillaridae) that is may be suitable for release. However, the colony has undergone considerable inbreeding and it has not been possible to replenish the stock. In addition, establishment success of this microlepidopteran likely would be jeopardized by parasitoids already established in the Islands. Furthermore, we have little evidence that this agent would have a significant impact on its target. This species was probably a poor choice as a potential agent using Balciunas' criter~a (this volume). The absence of significant agents in Macaronesia may be explained by the fact that the Macaronesian colonies of fayatree were components of an isolated vegetation type now an outlier of the once more wldely distributed laurisllva (sub-tropical rainforest) widespread in the Mediterranean and near East during the Tertiary. Insects adapted to fayatree may not have reached the distant Macaronesian Islands that are at least 1000 km from the Iberian Peninsula. Populations of fayatree in many areas of Portugal north of Lisbon appear to have been planted. Natural populations from the Algarve, Portugal, and the Atlas Mountains were not relocated. We have also started work on the herbivores of related species of fayatree in Venezuela where several potential agents, including a promising stem borer, have been identified. Further development of these species is on hold awaiting their shipment to Hawaii. There is little hope of getting the necessary permits until the political situation in the country has settled down. Fayatree continues to expand in natural areas and ranchland. Though not a high profile weed, Vitousek and Walker (1989) have shown that it modifies ecosystem processes. These modifications are of such magnitude that fayatree remains among the highest priority weeds for the Forest Pest Biological Control Program. Kahili ginger - Hedychium gardnerianum Roscoe (Zingiberales, Zingiberaceae). Anderson and Gardner (1999) have studied a strain of Ralstonia solanacearum (E.F. Smith) Yabuuchi et a/. (Bacteria, Pseudomonaceae) that attacks kahili ginger. They expressed considerable optimism that this fungus has the potential to bring about longterm control of this pest including the suppression of seedling establishment. The slow-acting nature of this pathogen may be beneficial in that native species will have a chance to recover before weeds overwhelm them. The establishment of the bacterium is somewhat difficult generally requiring physical damage. Nevertheless, the bacterium has been established in some populations in the Islands. Evidence suggests that the density of plants in these areas is declining. Perhaps the most encouraging aspect of this disease is that seeds do not germinate or damp off soon thereafter where the bacterium is present in the soil. EPA approval may be required before the fungus can be broadcast as a biocide. In the meanwhile, use of this pathogen is limited to local application only though experiments on mass culture, optimal dosage, and alternative inoculation techniques are underway. A potential conflict of interest is that it attacks edible ginger (Zingiber officinele Roscoe - Zingiberales, Zingiberaceae). The difficulty of dissemination and establishment of the bacterium suggests that this concern is not a significant problem. The infestations of kahili ginger are well above the areas were ginger is grown commercially.

100 Miconia - Miconia calvescens DC (Myrtales, Melastomataceae). See Killgore (this volume). As a consequence of an exploratory trip report by Burkhart (1996), the initial focus of biocontrol research on Miconia targeted pathogens. The project initially was supervised by the Tri-Isle RCBD's Melastome Action Committee, which did an admirable job soliciting funds, while the HDOA funded exploratory work and the screening of the first agent. Well over $lm was obtained to contain the Miconia infestations while exploration for biological control agents was underway. Funding and in-kind resources came from diverse sources, including the affected counties, Hawai'i Legislature, The Nature Conservancy-Hawai'i and the government of French Polynesia. Eliminating large fruiting trees principally by spraying herbicide from helicopters was the first priority. Some trees in steep sided gullies could not be treated. Most were later controlled by crews abseiling down the gully walls. Manual eradication of juvenile trees and seedlings continues. The infestations have been reduced substantially. The Melastome Action Committee subsequently became the Maui lnvasive Species Committee (MISC) in This development diffused the focus of the Action Committee somewhat. It might have been more effective as a separate entity targeting Miconia control specifically, albeit under MISC. Development of effective biological control agents is sporadic. Though money has been obtained for the containment program, funding for the biological control program has been erratic. The biological control development project itself has solicited funding and, in one instance, has run into conflict with MISC. These potential conflicts are a significant problem in Hawai'i's attempt to manage established alien species. There are so many that need attention that it will be extremelv difficult to maintain sufficient focus on the research necessarv to establish an adequate biological control program against one particular species. he consequent stop-and-go already evident in the Clidemia and Myrica programs could become the norm. Burkhart (1996) recommended that pathogens should be the initial focus in biological control. His exploratory work in Central America had not identified an obvious insect candidate. Several other factors (ease of handling, lack of potential biotic interference, rapid spread) also suggested that pathogens would be the best candidates in this instance. Mycological studies in Brazil had already identified an anthracnose disease causing agent, Colletotrichum species (see Kilgore, this volume). The fungus was released in After some preliminary disappointing results, the fungus is now established on the Big Island, spreading and having noticeable effects on at least one of the major infestations. Seedlings appear to be particularly susceptible but leaves are lost from the canopy increasing light levels on the forest floor. Quantitative studies are now underway to determine the magnitude of the impact. Four other potential fungal control agents are known: a black pimple leaf disease, Coccodiella myconae (Duby) Hino 8 Katuamoto (Phyllacorales, Phyllacoraceae), which causes extensive damage. It is an obligate parasite, which has been difficult to transfer from plant to plant. In Brazil, five hyperparasitic fungi have been collected from the pimples; a leaf spot disease, Pseudocercospora tamonae (Chupp) Braun (Deuteromycotina, Dematiaceae), which also causes extensive damage. It also attacks seedlings of some myrtaceous species and will need extensive evaluation before consideration for release; a tar spot disease. Guignardia sp. (Dothideales. Mycosphaerellaceae), a new species. Its potential is not fully understood but it could be very useful; a leaf blight, Kuronomyces sp. (Mycelia sterilis,?basidiomycetes), which has not been evaluated nut produces a strong blight on affected leaves.

101 The Miconia infestation in Hawai'i is conceived generally to be such a significant threat that further exploratory work on potential insect agents has been encouraged recently. A cooperative exploration and development effort has been established with the University of Costa Rica supported by a variety of funding sources. A psyllid (Haplaphalare sp. - Homoptera, Psyllidae) that attacks shoot tips appears to have promising potential. It can be manipulated easily in the greenhouse. An evaluation of its impact on the plant is underway. Further work on a processionary caterpillar Euselasia chrysippe (Bates) (Lepidoptera: Riodinidaae) has just started. Another species E. bettina (Hewitson) is also under consideration. There is also a leaf-mining nematode (Ditylenchus drepanoce~us Goodey - Nematoda, Anguinidae) that causes extensive damage and appears to be host-specific. Nematodes have not been used for biological control in Hawai'i that may preclude its consideration. Strawberry guava - Psidium cattleianum Sabine (Myrtales, Myrtaceae). See Wikler (this volume). This project is high priority because of the severe impacts of the weed and consensus that it is the most widespread, disruptive species in native rainforests (Smith 1985). The program was sponsored by the National Park Service principally and later transferred to the US Geological Survey. A major constraint on development of agents has been the requirement that it not attack the closely related common guava (P. guajava L.). Initial skepticism in finding an agent with this degree of specialization was overcome by our Brazilian colleagues who found five host-specific gall-forming insects, one of which (Tectococcus ovalus Hempel - Homoptera, Eriococcidae) should be the subject of a release petition in the near future. At least three potential candidates were rejected because they occasionally attacked common guava. Although requiring considerable travel and communication, the cooperative effort with the College of Forestry, University of Parana. Curitiba has worked well. The majority of the research has been published. In this particular case the lack of an oversight committee for the project was only a minor impediment because funding came from a single agency that acted as the oversight body. The project has taken ten years and the work conducted principally by graduate students. Since strawberry guava has been a dominant element in native communities for at least 75 years, the long duration of the project has not been seen as a problem. Speed of resolution was less of a priority than the host specificity of potential agents and verification that the impact of potential agents is significant. Tibouchina - Tibouchina herbacea (DC) Cogn. (Myrtales, Melastomataceae). Our success with development of the strawberry guava project led to several other collaborations with Brazilian entomologists, including exploration for agents targeting Bidens pilosa L. (Asterales, Asteraceae), Pomacea caniculata (Gastropoda, Ampullaridae), and 1. hehacea. The Bidens project was abandoned when it became clear that obtaining sufficient material of the many endangered endemic species in this family for host screening would be difficult, if not impossible. The Pomacea studies focused on egg parasites; none have been found to date. 1. hehacea is part of a complex of closely related species in southeastern Brazil. Species are distinct though the delimitation of some probably needs revision. Although our surveys are by no means complete it appears that a common suite of insects attacks all species but a few appear to attack only one or two species. We had enormous difficulties locating 1. hehacea populations initially because it is an ephemeral, ruderal species and most of the previously collected sites were disturbed. The size and

102 behavior of the plant in Brazil and Hawai'i is very different. In Brazil it is a geophyte rarely above l m in height dying back each year. In Hawai'i it can grow up to 3-4m and the previous year's stems survive the dormant period forming rank sprawling stems from which new shoots arise the following year. The thickets that are formed are difficult to traverse and exclude all other species. The sprawling nature of the growth smothers adjacent bushes, gradually increasing the size of the infestation. Syphma ubembensis (Coleoptera: Chrysomelidae) appears to be specific to T. herbacea and one or two other closely related species. It damages the leaves heavily essentially skeletonizing them. The magnitude of the impact is under investigation. A species of Schmnkensteinia (Lepidoptera: Schrenkensteiniidae), a leaf skeletonizer, is a promising potential biological control agent. One species from the genus, Schmnkensteinia festaliella has been released against Rubus argutus Link (Florida prickly blackberry) in Hawai'i. It has been quite effective even though the eggs are heavily attacked (up to 50%) by the egg parasitoid Trichogramma chelonis. The larvae are infrequently parasitized (Ramadan, pers. comm.). Even with this high level of parasitism, damage to the target plants is high though there is considerable variation in different situations. We expect to find a similar pattern of parasitism on the Brazilian species and hopefully the same level of feeding activity on the target plant. We have not progressed very far with this species because it is not abundant. There are also two species of Anthonomus (Coleoptera: Curculionidae) that appear promising; they now are undergoing life history and impact studies in Brazil. A species of Margamdisa (Coleoptera: Chrysomelidae) also may prove to be useful but we do not know which plant species the larvae attack. Other forest weed projects. At least two efforts to develop biocontrol agents have been conducted outside the auspices of the Steering Committee as a result of the specific interests of the researchers involved. The most successful of these was the use of Entyloma compositarum (Basidiomycetes: Ustilaginales) against Maui pamakani, Agemtina adenophora (Spreng) R. King & H. Robinson (Trujillo 1985, Trujillo et al. 1988). Infestation of plants during wet periods coupled with the impact of previously introduced insects has resulted in other plants invading monotypic stands and in some cases replacing them. I know of no quantitative evaluations of the impacts to date. The studies on banana poka conducted in Colombia were supported by DOFAW outside the oversight of the Committee. The leaf spot fungus mentioned earlier was discovered, evaluated and released under this program. DISCUSSION Development of biological control agents for forest weeds is generally taken as a last resort after all other control methods have failed. The only exception to date has been the Miconia calvescens project for which research on potential biological control solutions was included with conventional control strategies initially. This unusual concurrent approach was the result of almost unanimous agreement that containment could be only a stopgap measure while exploratory studies were underway. Subsequent discovery of the wide distribution of Miconia in Hawai'i illustrated our inadequate understanding of the extent of the invasion and convinced the skeptics that biological control was the only long-term management option. To date, the priority of forest weeds to target for biological control research has been simple; species attracting funding support receive the highest priority. Thus research has been dictated by whichever management group has had funding to support

103 a project. Neither the creation of priority lists nor the scientific basis of such lists had much impact on implementation of a research program. Interest groups from each island have different priorities. For example, miconia was a candidate for biological control on Maui afler its escape into the forests above Hana was discovered. That support continues with strong encouragement and funding. On Kaua'i and O'ahu miconia was contained immediately afler the threat was understood. Continuing control programs should extirpate it within a few years. On the Big Island, however, initial indifference was followed by aggressive containment until even the most skeptical were convinced that biological control was the only long-term solution. Unfortunately, this realization by the latter group has not resulted in contributions to the biological control research program to date. Consensus, however, has developed recently in a general focus on melastomes. This family, many or most of which are early colonizers, generally is perceived as totally undesirable in Hawai'i; only one species, Medenilla magnifica, has not become a problein so far, although recent observations suggest that it too can reproduce in Hawai'i. It is still too early to tell whether or not this consensus will result in an adequately funded program. Much of the decision-making revolves around key enthusiasts. Another family high on every managets list for control is the grasses. However, biological control has not been considered against this group because of the perception that species-specific agents would be difficult to find and a general misconception that state law forbids importing organisms that attacked grasses as a protection of the once-dominant sugar industry. For a number of reasons scientists resident in the native range of pest plants are often better able to conduct exploratory and host-screening studies more effectively. More thorough evaluations of the insect fauna and pathogens can be made during yearround studies. The life history of potential agents can be studied in natural surroundings, providing valuable insights into host specificity, the impact of the potential agent on the target organism, rearing techniques, etc., all of which reduce the time required for quarantine work in the US. In addition, impacts of parasitoids, predators and hyperparasites can be evaluated. Of course, for this model to be successful, the lead scientist in Hawai'i must be prepared to travel, work with the foreign counterparts and to spend considerable time working on administrative necessities. This research model can also be highly cost effective because of the lower costs compared with sending highly paid research scientists from the U.S. Some countries may be prepared to add scholarships or facility enhancement to projects bringing in foreign funding. Promotion, development and/or expansion of entomological, plant pathology and biological control research abroad are decided benefits. Our cooperative programs in Brazil have enabled Australian and South African projects to develop their own cooperative programs there. In fact, many countries now require scientific cooperation with local scientists without which export permits become unobtainable. The main costs of this approach are that it generally takes longer than aggressively focused foreign work by U.S. biological control specialists because most studies are part of student postgraduate training. Since most forest weeds do not cause emergency management situations, a few extra years before the introduction of potential agents is not a major problem. High administrative responsibilities and occasional breakdowns in communication also present challenges. In Hawaii, the formation of an action committee for each weed has proven highly effective. The committee has included representatives from federal and state agencies, NGOs (in Hawai'i principally The Nature Conservancy Hawai'i), ranching, plantation and horticulture industries, the conservation community, in some instances the hunting community, and researchers. That is, the committee should represent the entire