Landscape Insects This laboratory session covers selected insects of trees, shrubs, and turf. To provide some structure for a very broad range of plants and insects, the specimens and materials provided in this lab session are arranged in broad categories -- defoliators, sap-sucking insects, gall-makers, wood borers and bark beetles, and turf insects. Within these groups a few common examples are presented as representatives of many, many more species with similar life histories. In the previous lab on field crop insects, specific sampling methods and thresholds were summarized because the damage and the economic impact of that damage are moderately well established for field crop pests. Well defined thresholds for control of landscape insects are much less common. Defoliators eastern tent caterpillar, Malacosoma americanum (Fabr.) (Lepidoptera: Lasiocampidae), and fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lasiocampidae) bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae) Sap-sucking insects leafhoppers, including potato leafhopper, Empoasca fabae (Harris) (Hemiptera: Cicadellidae) aphids (Hemiptera: Aphididae) scale insects, including cottony maple scale, Pulvinaria innumerabilis, (Rathvon) (Hemiptera: Coccidae), pine needle scale, Chionaspis pinifoliae (Fitch) (Hemiptera: Diaspididae), and oystershell scale, Lepidosaphes ulmi (Linnaeus) (Hemiptera: Diaspididae) Gall-makers hackberry psyllid, Pachypsylla celtidismamma (Riley) (Hemiptera: Psyllidae) horned oak gall wasp, Callirhytis cornigera (Osten Sacken) (Hymenoptera: Cynipidae) maple bladder gall and maple spindle gall mites, Vasates spp (Acari: Eriophyidae) Wood borers and bark beetles Longhorned beetles (Coleoptera: Cerambycidae): Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) and pine sawyers, Monochamus spp. Metallic wood boring beetles (Coleoptera: Buprestidae): emerald ash borer, Agrilus planipennis Fairmaire, and bronze birch borer, Agrilus anxius Gory ash/lilac borer, Podosesia syringae (Harris) (Lepidoptera: Sesiidae) bark beetles (Coleoptera: Curculionidae: Scolitinae): smaller European elm bark beetle, Scolytus multistriatus (Marsham), and mountain pine beetle, Dendroctonus ponderosae Hopkins Turf insects White grubs (Coleoptera: Scarabaeidae): annual white grub / masked chafer, Cyclocephala spp., and Japanese beetle, Popillia japonica Newman Sod webworms, Crambus spp. and others (Lepidoptera: Crambidae) In addition to these pest species, a few other insects of common interest are presented with this lab: Honey bees, bumble bees, carpenter bees, and sweat bees Yellow jackets and the bald-faced hornet 1
Defoliators 1. Eastern tent caterpillar and fall webworm Among the most common defoliators of trees and shrubs in Illinois are the eastern tent caterpillar, and the fall webworm. Tent caterpillars hatch in the spring from overwintered eggs, and larvae feed on trees as they first leaf out. Fall webworms overwinter as pupae, and moths emerge and lay eggs in early summer. Larval "nests" of the fall webworm become evident in late summer. Above left: Eastern tent caterpillar egg mass (Univ. of Illinois). Above center: tent caterpillars on webbing (Univ. of Wisconsin). Above right: Eastern (L) and forest tent caterpillar larvae (Ohio State Univ.). Below: Eastern tent caterpillar moth. Above: Fall webworm adult(left), larva (center), and webbing (right) (Oklahoma State University). For the eastern tent caterpillar, notice how egg masses surround a small twig and are covered with a shiny, dark brown coating. Eastern tent caterpillars secrete webbing or tents at the crotch of branches, and although the larvae rest within these tents, they leave them to feed on exposed foliage 2
anywhere on the host plant. In contrast, fall webworm larvae make nests at the tips of branches, and they feed on the foliage enclosed within their webbing. Outbreaks of tent caterpillars have been linked to mare reproductive loss syndrome in Kentucky. It appears that mares accidentally consume larvae and that the hairs on the larvae imbed in the lining of the alimentary canal and trigger bacterial infections that lead to miscarriages (http://www.ca.uky.edu/gluck/newsmedalertetc.asp). In most instances infestations of tent caterpillars or fall webworms are unsightly but not extremely harmful to the host trees. These insects can be controlled by removing nests (of fall webworm) or tents when larvae of tent caterpillars are resting on the webbing. Bacillus thuringiensis kurstaki (or aizawai) (Bt) is often recommended where insecticides must be used because sprays containing this bacteria are toxic only to caterpillars. References: Bessin, R. 2003. Eastern Tent Caterpillar. http://www.ca.uky.edu/entomology/entfacts/ef423.asp Mazzey, K., and M. Maziuk. Undated. Fall Webworm. http://woodypests.cas.psu.edu/factsheets/insectfactsheets/html/fall_webworm.html 2. Gypsy moth. Another well-known example of a Lepidopteran defoliator is the gypsy moth. This insect was introduced into North America in 1869 by a French naturalist trying to start a new silk industry. It has since spread to threaten a wide range of deciduous trees. It winters in the egg stage, and eggs may be laid on a variety of surfaces... including travel trailers, moving vans, and other vehicles. As a result, its movement to new areas is aided by its hitch-hiking as well as its local dispersal. This hitch-hiking dispersal is especially important because adult females do not fly (even though they have wings). Left: Gypsy moth adult male (darker) and female (Penn State Univ.) Center: Female and egg mass (US Forest Service). Right: Gypsy moth larva (US Forest Service). Read the brief fact sheet provided at this station to understand more about this insect. The web site that presents this fact sheet (at http://www.fs.fed.us/ne/morgantown/4557/gmoth/) includes links with more information on its life history, its natural enemies, its management, and its historic and predicted spread. The maps presented here are taken from this web site. 3
Reference: Liebold, S. 2003 and updates. Gypsy Moth in North America. http://www.fs.fed.us/ne/morgantown/4557/gmoth/ 4
3. Bagworm. We usually think of Lepidopterans as butterflies or moths with well developed wings and as larvae that crawl around, quite visible on leaf surfaces. There are lots of exceptions to this generalization, however, and the bagworm is a common one. Bagworm larvae construct cases of foliar debris around themselves and feed from within this protective "bag". Females remain larvaiform and mate at the opening of their larval case, then they lay eggs (500 1,000 apiece) within it. In central Illinois, bagworms are most common on arborvitae and similar conifers, but they also may feed on several common broad-leafed trees as well. Left: bagworm larva and bag (University of Nebraska). Right: adult male (E.D. Cashatt, Illinois State Museum). Like many other arthropods that are wingless as adult females, bagworms still have a means of dispersal other than crawling. Young larvae, upon hatching from overwintered eggs, spin a silken thread and hang from it to attach to passing animals or to be windblown to new locations this ballooning behavior is not unlike that seen in the twospotted spider mite. Hand-picking is often advised as a means of controlling bagworms on relatively small plants. Because larvae are concealed in a bag constructed of plant debris, they are not highly susceptible to conventional insecticides. Applications of insecticides that contain Bacillus thuringienis (kurstaki or aizawai) can be the most effective, as larvae consume spores and toxins when they feed on treated foliage. References: Mazzey, K., and M. Masiuk. Undated. Bagworm. http://woodypests.cas.psu.edu/factsheets/insectfactsheets/html/bagworm.html 5
Sap-sucking Insects Below are a few examples of the many sap-sucking insects that infest trees and shrubs, but indeed only a very few. For the families presented here (Aphididae, Diaspididae, and Coccidae), there are dozens if not hundreds of species that feed on trees and shrubs. Moreover, there are several other families of sapsucking insects not presented here at all plant bugs, spittlebugs/froghoppers, tree hoppers, plant hoppers, psyllids, and more. The reference displayed in lab Insects that Feed on Trees and Shrubs, by Johnson and Lyon provides a good overview and excellent photos. 4. Leafhoppers, including potato leafhopper. Many leafhoppers feed on a wide range of trees and shrubs. As noted in the lab on field crop insects, when leafhoppers insert their stylets into plant foliage, they may injure plants in one of four ways: (1) direct removal of cell contents, reducing photosynthate availability; (2) transfer of plant pathogens (3) injection of salivary toxins that kill cells around feeding sites; and (4) secretion of honeydew that supports growth of sooty molds on plants surfaces. In trees and shrubs, a few examples include: Rose leafhopper and white apple leafhopper feed on roses, apples, and many other plants, removing chlorophyll and leaving white, stippled areas on leaves; their honeydew secretions also contribute to sooty mold on foliage. Leafhoppers known as sharpshooters in the genus Graphocephala (including rhododendron leafhopper) are known to carry pathogenic microorganisms. The potato leafhopper is a serious pest of several trees and shrubs, including maples, birch, and redbud. The salivary toxins it injects when it feeds cause leaf cupping and curling and the cessation or distortion of growth of new shoots. Potato leafhopper injury on apple (left) (West Virginia University) and maple (University of Illinois). Use the reference below and look over pages 412-419 in Insects that Feed on Trees and Shrubs for more information about leafhoppers. Reference: Anon. Undated. Leafhoppers. http://www.entomology.umn.edu/cues/web/162leafhopper.pdf 6
5. Aphids (and adelgids). Spirea aphid on spirea (Jim Schuster, University of Illinois) http://www.urbanext.uiuc.edu/shrubselector/detail_problem.cfm?pathogenid=102 First, remember who the aphids are pear-shaped insects that may be winged or wingless as adults, their sucking stylet appears to originate from the base of the head, and cornicles (tailpipes) near the end of the abdomen are used in their identification. Also remember that, in general, eggs are part of the life cycle only for overwintering; they hatch into females that develop to the adult stage and without mating give birth to more live females (parthenogenesis). Many develop for a few generations in the spring on a tree or shrub host and then migrate to an annual plant during the summer (soybean aphid winters on buckthorn, a woody shrub), but others remain on their woody host(s) all year-around (such as giant willow aphid, spirea aphid, and rose aphid). Aphid feeding on new leaves and shoots may cause leaf curling and distortion; large numbers of aphids removing sap from plants can reduce growth and vigor. The sticky liquid excreted by aphids (honeydew) is sometimes a nuisance, and it provides energy for the growth of sooty molds that reduce the attractiveness of foliage. Many natural enemies attack aphids on trees and shrubs. Woolly aphids and adelgids that feed on pine and spruce (family Adelgidae) secrete white, waxy coatings that cover their bodies; these insects commonly cause galls, as do some other aphids. Note the specimen(s) presented, and use the reference provided to answer any questions in your assignment. Also briefly look over pages 74-85 and 292-317 in Insects that Feed on Trees and Shrubs for more examples of aphids and adelgids on woody plants.. Reference: Cranshaw, W. 2004. Aphids on Shade Trees and Ornamentals. http://www.ext.colostate.edu/pubs/insect/05511.pdf 7
6. Scale insects: soft scales (Coccidae) & armored scales (Diaspididae). Again, realize how little we scratch the surface on scale insects with the few examples we cover in this lab assignment. A quick scan of Armored Scale Insect Pests of Trees and Shrubs by Miller and Davidson (well over 400 pages, with lots of great illustrations and identification guides) gives you an idea of how diverse just the armored scales are (without covering the soft scales). Several cottony scales and armored scales are pests of trees and shrubs. Specimens of cottony maple scale (a soft scale), pine needle scale, and oystershell scale are provided along with a reference that provides a brief summary on each of these insects. Top left: cottony maple scale (North Dakota State University); top right: oystershell scale (University of Illinois); bottom left: pine needle scale (and twice-stabbed lady beetle); bottom right: pine needle close-up showing small red crawlers. Bottom photos from Cornell University. See pages 115-116 and pages 265-268 in Armored Scale Insect Pests of Trees and Shrubs for closeups of pine needle scale and oystershell scale and scan the information about their life cycles. Also look over examples of other scale insects. Rarely are insecticides used regularly to control scale insects on trees and shrubs, but when they are, successful control often depends on (1) timing applications so that a large percentage of the population is in the crawler stage and exposed the chemical at or soon after application; (2) using dormant oils or similar materials when a large portion of the population can be suffocated under scales by the oil film deposited on trunks, branches, or twigs; or (3) using systemic insecticides that move into the plant sap to kill scale insects as they feed. Reference: Wawryynski, R., and M. Ascerno. 2009. Scale Insects of Trees and Shrubs. http://www1.extension.umn.edu/garden/insects/find/scales/ 8
Gall-making insects 7. Hackberry psyllid, horned oak gall wasp, maple bladder gall mite and maple spindle gall mite. Galls are plant tissues that are produced in response to injury or infection. Insects and other arthropods trigger gall production by feeding on or laying eggs into plant tissue. Homopterans (adelgids and psyllids) and Hymenopterans (especially cynipids) are among the most common insects that are gall inducers. Mites in the family Eriophyidae also cause a variety of leaf galls. Left: Hackberry nipple gall (University of Kentucky). Right Horned oak gall (Oklahoma State University). Left: Maple bladder gall (University of Kentucky). Right: Maple spindle gall (Ohio State University). Examine the specimens provided for the four galls shown above, and briefly look over the other examples of arthropod-induced galls. Check the fact sheet, Gall-Making Insects and Mites, to get an idea of what insects cause common galls on woody plants. 9
References: Bogran, C.E., B.M. Drees, and J.L Hidgeons. 2006. Gall-making Insects and Mites. http://insects.tamu.edu/extension/publications/epubs/e-397.cfm Dixon, W.N. 2006. Gall Wasps, Callirhytis quercusclaviger (Ashmead) and Callirhytis cornigera (Osten Sacken) (Insecta: Hymenoptera: Cynipidae). http://edis.ifas.ufl.edu/in664 Wood borers and bark beetles Many roundheaded wood borers and flatheaded wood borers develop in trees that are already in decline, and although the trees may die following infestation, the wood borers seldom are the primary cause for decline or death. The beetles that we know best as pests are the exceptions to this rule. For general information on several roundheaded and flatheaded borers, see http://www.fs.usda.gov/internet/fse_documents/stelprdb5186647.pdf. 8. Longhorned beetles / roundheaded wood borers. Two examples of the more serious pests in the family Cerambycidae are presented at this station. One is an introduced species that is an extremely serious pest that kills hardwood (deciduous) trees the Asian longhorned beetle. The other is a native genus, Monochamus, the pine sawyers. Larvae of these beetles develop in conifers. Pine sawyers are serious pests of pines because they are vectors of pinewood nematode. Asian longhorned beetle adult (left) and emergence hole from tree trunk (right) (USDA Forest Service). Asian longhorned beetle was first detected in North America in New York in 1996. It was found near Ravenswood, IL, in 1998 and in New Jersey in 2004. New infestations were detected on Staten Island, NY, in 2007. Infested wood has been found in warehouses in several areas around the country. Larvae of this beetle tunnel in maple, birch, poplar, willow, ash, and elm (as well as other species), and their feeding injury kills otherwise healthy trees. Where new infestations are found, susceptible trees in the infested area are cut down and chipped or burned in efforts to eradicate this pest. Eradication efforts in the Chicago area appear to have been successful, as no new beetles or infestations were detected there in recent years. 10
The pine sawyers are so named because the larvae make loud noises while cutting / feeding in wood. They typically infest trees that are stressed or dying or recently dead trees, including trees that have been cut or felled by storms. Young larvae feed near the surface, just below the inner bark, and older larvae first go deeper into wood, then turn back toward the surface. On their own, too few pine sawyers infest healthy trees to cause severe injury. However, where drought stress attracts these insects to Austrian or Scotch pine, especially where these trees are grown in warm climates, sawyers can be instrumental in the death of the trees because they carry a pathogenic nematode pine wilt nematode that infests the vascular system and kills trees. Pine sawyer, Monochamus spp., adult (left) and larva (right) (Oklahoma State University). References: USDA APHIS, 2007. Asian Longhorned Beetle: Questions and Answers. http://www.aphis.usda.gov/publications/plant_health/content/printable_version/faq_alb_07.pdf. Oklahoma State University. Undated. http://www.ento.okstate.edu/ddd/insects/pinesawyerbeetle.htm. 11
9. Flat headed wood borers / metallic wood-boring beetles. Again we ll cover a native species and an exotic species that are serious pests (even though many other flatheaded wood borers infest trees only after they are already in decline). The bronze birch borer is a native species; emerald ash borer is exotic. Adult bronze birch borers are about ½ inch long and an iridescent brownish-black (bronze) in color. Females typically lay eggs in bark crevices in June, and larvae that hatch from these eggs tunnel in phloem and then xylem tissue to feed. Larvae may require one or two seasons to develop (depending on location and temperatures), and they pupate in April or May. They are most prevalent in white birch, paper birch, and yellow birch. Keeping these birch cultivars otherwise healthy (good planting sites, irrigation, etc.) can reduce losses, but this insect can kill birch trees. River birch, Japanese birch, and Heritage birch are resistant to this insect. Bronze birch borer symptoms of attack (left); adult beetle and emergence hole (right) (Ohio state University). Emerald ash borer should be a familiar insect by now, as it has been the object of a great deal of press in Illinois and elsewhere in the eastern U.S. over the last few years. The reference listed below provides plenty of information on this insect s appearance, life history, and origins be sure to jot down a brief summary of that information: 12
Known distribution, September, 2013: Emerald ash borer larva (left) (Purdue University) and adult (right) (USDA). References: http://www.emeraldashborer.info/files/multistate_eabpos.pdf Gibb, T., and C. Sadoff. 2007. Bronze Birch Borer. http://extension.entm.purdue.edu/publications/e-50.pdf Emerald Ash borer. http://www.emeraldashborer.info/index.cfm 13
10. Ash/lilac borer. Introductory coverage of clearwinged moths in general and the ash and lilac borer(s) specifically is presented in the reference provided. Several clearwinged moth larvae are very damaging to ornamental trees and shrubs. The peachtree borer and lesser peachtree borer damage flowering plums; viburnum borer damages viburnum, and lilac / ash borer damages ash and lilac. These insects typically attack otherwise healthy trees, and their damage can kill trees. Controlling these insects with insecticides applied as trunk sprays is possible and practical, but applications must be made before larvae have entered the tree, and extended periods of moth flight and egg-laying require repeated applications. Reference: Lilac borer adult (left) (Kansas State University) and larva (right) (Ohio State University). Clearwing borers. http://www.entomology.umn.edu/cues/web/088clearwingborers.pdf Bark beetles 11. Smaller European elm bark beetle and mountain pine beetle. Bark beetle larvae tunnel just beneath the bark of trees, destroying the cambium. Many species attack trees that are weakened or dead, but some species are pests of otherwise healthy trees, especially when beetle populations are extremely high and their attack overcomes tree defenses. Bark beetles carry fungi that grow in their tunnels... these fungal colonies serve as food for the beetles. In some instances, the fungi are serious pathogens of the host tree as well. This is true for the Dutch elm disease pathogen, Ophiostoma ulmi, the fungus carried by the elm bark beetles. The native elm bark beetle and the smaller European elm bark beetle both carry the fungus that causes Dutch elm disease. 14
The European elm bark beetle was first detected in the U.S. in 1909, and the Dutch elm disease fungus was detected first in 1930. By the 1960s and 70s the disease had wiped out almost all mature American elms in North America. Smaller European elm bark beetle (left) (Oregon State University) and larval galleries (right) (University of Illinois). Mountain pine beetle (Colorado State Univ.) Mountain pine beetle is a very widespread bark beetle in the western United States. For those who have traveled to Colorado or other mountain states in recent years and noticed large areas of coniferous forest where the needles are brown and the trees are dying, know that drought conditions followed by mountain pine beetle infestations are the primary causes. Don t devote a lot of time to learning lots of details on this insect... just be aware of it, know that it is an important component of western forest ecosystems and that outbreaks can have devastating effects. References: Cornell University. 2005. Dutch Elm Disease. http://plantclinic.cornell.edu/factsheets/dutchelmdisease.pdf Leatherman, D. 2005. Mountain pine beetle. Colorado State University, http://www.ext.colostate.edu/pubs/insect/05528.html. 15
Turf insects 12. White grubs. White grubs are the larvae of beetles in the family Scarabaeidae. In Illinois and much of the north central United States, the northern and southern masked chafers ("annual white grubs") are the most common and damaging species. In the eastern United States, Japanese beetle larvae are more common. As the Japanese beetle has spread across Illinois, it has become more important as a pest of lawns and turf. First, look over the specimens of some common adult beetles in the family Scarabeidae provided at this station. These species are at least somewhat associated with turf; many other species develop in dung as larvae instead of feeding on plant roots. Examine the Ohio State University fact sheet that compares the characteristics of these and other species. List the species exhibited here as adults: Next, look over the illustrations (in the Ohio State University fact sheet) that show the raster patterns on larvae of common species, and identify the specimens provided. If given this identification guide and a specimen of one of these larvae for the final lab exam, you should be able to use the key to identify it. Describe in your own words the difference in the raster pattern on larvae of annual white grub (Cyclocephala spp.) vs. Japanese beetle (Popillia japonica) vs. perennial (=true) white grub (Phyllophaga spp.). Which of these species is/are the most common pest grubs in Illinois lawns? 16
Turf rolled back to reveal grubs (Kansas State University). Masked chafer (annual white grub) life cycle and damage: Partially mature larvae move down a few inches in the soil to overwinter, return to the root zone to feed in the spring, then pupate in mid to late May. Adult beetles emerge in June and July (sometimes triggered by rains), mating occurs, and females lay eggs, particularly in grass growing in moist, well-drained, fertile soils. Larvae hatch and begin feeding in August, and they continue to feed well into the fall. They chew off and consume grass roots just below the soil - thatch interface, and damage to turf is most apparent in August and September, because moisture stress often accentuates the root injury at this time. Severely damaged turf may show dead patches that can be lifted or rolled back like a carpet. Life cycle, masked chafer / annual white grub (University of Nebraska). Sampling and control: Lawns and turf can be sampled for the larvae of masked chafers in August to determine whether or not control is needed. Scouts cut through turf on 3 sides of a 6-inch or 12- inch sampling frame, then roll it back (sometimes cutting roots to make this possible) to check for and count larvae. Thresholds vary among turfgrass species and according to the vigor of turf at any given site, but insecticides are often recommended if counts exceed 8 to 10 grubs per square foot (maybe up to 20 in vigorous turf). Lawns and turf that are watered frequently in late June and July are especially attractive to egglaying beetles (especially during very dry summers), and these sites may be heavily infested. 17
Beetles are also attracted to lights, and egg-laying can be concentrated under outdoor lights in residential lawns. The life cycle of the Japanese beetle is very similar to that of the annual white grub, although this species may cause a little more damage as it resumes feeding in the spring of the year. Note in the University of Kentucky fact sheet on this insect the list of landscape trees and shrubs that damaged severely by adults of Japanese beetles and species that are much less often damaged. In turf, Japanese beetle larvae may be controlled (at least in part) by using commercial preparations of "milky disease" bacteria (Bacillus lentimorbus and Bacillus popilliae); these pathogens are formulated and sold as microbial insecticides. Milky disease is NOT effective against the larvae of the masked chafers. Japanese beetle life cycle (University of Kentucky). 18
Other scarab beetle larvae (white grubs) can also be pests of lawns and turf. Briefly review the information on these species provided in the Handbook of Turfgrass Insect Pests displayed at this station. References: Brandenburg, R.L., and M.G. Villani. 1995. Handbook of Turfgrass Insect Pests. Entomological society of America, Lanham, MD. Shetlar, D., and J. Andon. 2012. Identification of White Grubs in Turfgrass. http://ohioline.osu.edu/hyg-fact/2000/pdf/2510.pdf Townsend, L. Undated. Japanese Beetles. http://www.ca.uky.edu/entomology/entfacts/entfactpdf/ef409.pdf 13. Sod webworms. Left: Sod webworm adult (North Carolina State University). Right: Sod webworm larva (University of Florida). Several species of sod webworms are native to North America and common in the eastern United States. Larvae are light green to gray or brown, with light brown to black head capsules. They range from 0.6 to 1.1 inch long (16-28 mm) when mature. Moths are about ½- to 3/4- inch long, with a wing span of 0.6 to 1.4 inches (15-35 mm), and their labial palps project forward to give a snout-like appearance. They are slender, and when at rest their wings project back and are slightly wrapped around the body, giving them a tube-like appearance. They fly short distances in a zigzag pattern. Larvae overwinter, pupate and emerge as moths in spring, and 2 to 3 generations develop each season in Illinois. Egg-to-adult generation time is about 6 weeks on average. Larvae of the sod webworms feed on grass leaves, sometimes cutting grass blades and dragging them into the tunnels that the larvae make in thatch. Damage is usually greatest in the late summer and early fall, when populations are highest and grass may be stressed by heat and drought. To sample for webworms, scouts may use a "flushing agent" -- a solution of pyrethrins or liquid soap; the Illinois Home, Yard, and Garden Pest Guide recommends control if infestations exceed 2 per square foot. Birds often eat webworm larvae. Reference: Heller, P. 2007. Sod Webworms in Home Lawns. http://ento.psu.edu/extension/factsheets/sod-webworms-lawns 19
What sampling methods and thresholds are recommended in the Penn State reference on sod webworms? Your answer should include mention of a flushing or disclosing agent what does such an agent do? 14. Honey bees, bumble bees, carpenter bees, and sweat bees Reference: A bumble bee, Bombus sp. (University of Missouri). Wright, R., P. Mulder, and H. Reed. Honey Bees, Bumble Bees, Carpenter Bees, and Sweat Bees. Oklahoma State University. http://pods.dasnr.okstate.edu/docushare/dsweb/get/document-2292/epp- 7317web%20color.pdf Bumble bees of Illinois: http://beespotter.mste.uiuc.edu/topics/key/illinoisfieldguide.html. Colony Collapse Disorder: A Descriptive Study. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006481. Describe the differences in appearance and life history between bumble bees and carpenter bees. 20
15. Yellow jackets and the bald-faced hornet. German yellowjacket, University of Wisconsin. Baldfaced hornet. R. Bessin, University of Kentucky. References: Yellowjackets. http://en.wikipedia.org/wiki/yellow_jacket. Oswalt, D., E. Benson, and P. Zungoli. 2003. Baldfaced hornets. http://www.clemson.edu/cafls/departments/esps/factsheets/medvet/baldfaced_hornets_mv1 5.html Hahn, J., P. Pelletteri, and D. Lewis. 1996. Wasp and bee control. http://www.extension.umn.edu/distribution/horticulture/dg3732.html Describe the life history of bald-faced hornets. 21
Study Questions: What orders are represented as pests in the stations presented in this lab? Which of the pests covered in this lab or introduced / exotic? Which of the pests covered in this lab do not overwinter here? In what portions of the year are eastern tent caterpillars, fall webworms, and bagworms actively feeding on trees and shrubs? What name is given to the mobile first-instar of scales (before they settle and become sedentary)? What taxa (orders and or families) are common gall inducers? How can you distinguish annual white grubs, perennial white grubs, and Japanese beetle larvae from each other? Write a paragraph that tells the similarities and differences (morphological, behavioral, and/or ecological) in honey bees, bumble bees, carpenter bees, yellow jackets, and baldfaced hornets. Which insects covered in this lab are vectors of pathogens that cause plant diseases? (And what is a vector?) 22