Testing the Effectiveness of a Native Fungus to Control Ailanthus in Ohio Forests

Transcription

1 Testing the Effectiveness of a Native Fungus to Control Ailanthus in Ohio Forests Joanne Rebbeck, Don Davis, Joan Jolliff USFS Northern Research Station Penn State University

2 Ailanthus altissima Ailanthus or Stink Tree Tree of heaven The Ohio Woodland Journal Fall 2013 Kevin Lewis Matt Kasson

3 Ailanthus wilt found in PA forests Verticillium nonalfalfae Don Davis & Mark Schall Matthew Kasson Eric O Neil Penn State University Forest Pathology 2009 VA (6 sites) 2012 OH (3 sites) Earlier reports in 1915, , 1990s

4 Rapid Foliar Wilting

5 Declining Trees Dead trees

6 Kills vascular tissue Dying Ailanthus Healthy Ailanthus

7 Two Verticillium wilts that attack Ailanthus 1. Verticillium dahliae slow-killing >2 years common & widely distributed generalist **2. Verticillium nonalfalfae fast-killing <1 year more pathogenic infrequent

8 Fungal Isolate Comparisons Molecular sequencing identification All isolates are identical Pathogenicity on Ailanthus seedlings similar to PA and VA isolates Wilting began at 4 weeks Dead within 9 weeks Rebbeck et al Plant Disease 9 (7):999 Photo credit: Eric O Neal

9 Verticillium nonalfalfae Model Biocontrol Agent Native soil-borne fungus Highly selective for Ailanthus Natural transmission via root grafting, wounding Can persist in soil for years

10 Post-inoculation spread in PA canopy trees were inoculated 2011 >14,000 dead/dying trees and 10,000-15,000 sprouts killed Rate of spread ft/year Kasson et al 2014

11 Added bonus Ambrosia beetle may help move the fungus Euwallacea validus <1/8 long Euwallacea validus (female)(by J Hulcr) Hulcr, J

12 Regulatory Approval in Ohio Searched for naturally occurring infected stands ( ) Ohio Dept. of Agriculture approval for field studies in 2013 No regulatory issues with APHIS or ODA to use Ohio isolate (in state inoculum)

13 Host Range Testing: 71 species Kasson et al. Plant Disease 2015 Boxelder Japanese maple Striped maple (3%) Norway maple Red maple Sugar maple Red elderberry Staghorn sumac (16%) Poison-ivy Pawpaw Angelica tree European black alder Black birch American hornbeam Hophornbeam Japanese barberry Northern catalpa Doublefile viburnum Blackhaw Oriental bittersweet Burningbush Winter creeper Flowering dogwood Autumn olive Mountain laurel Great rhododendron Pink azalea Lowbush blueberry Silktree Eastern redbud Honey locust Black locust American chestnut American beech Northern red oak Chestnut oak American witchhazel Mock-orange Hickory Black walnut Northern spicebush Sassafras Corkwood Yellow-poplar Cucumbertree Black tupelo White ash American sycamore Hawthorn Apple Rome Sweet cherry Black cherry Multiflora rose Amur corktree Korean evodia White poplar Bigtooth aspen Royal paulownia Ailanthus American basswood Hackberry American elm Siberian elm Eastern red cedar Arborvitae Virginia pine Devil s walkingstick (17%)

14 Ohio Greenhouse Studies Greenhouse inoculations at Delaware Lab Ailanthus Oaks: black, chestnut, pin, red, scarlet, & white Hickories: bitternut, butternut, mockernut, pignut & shagbark Elm Ash Beech Tomato, alfalfa & soybeans To date no off-target effects

15 10 weeks post-inoculation

16 Ohio Field Research Demonstration study installed at Vinton Furnace and Tar Hollow State Forests in June 2014

17 Hack-n-Squirt Stem Injection of Ailanthus 1. Fungus is cultured on agar in lab 2. High concentration of spores in aqueous solution prepared 3. Ailanthus trees cut with hatchet & injected with fungus

18 2 weeks after inoculation

19 8 weeks after inoculation

20 15 weeks after inoculation

21 US FS Forest Health Program Biocontrol Grant Inoculated and monitoring Ailanthus in 5 SE Ohio forests since 2015 Monitoring for off-target effects Studying aftermath regeneration within inoculated stands Partners: Ohio Division of Forestry, Wayne National Forest, The Wilds, & Penn State

22 5 study sites: 4 plots inoculated + 1 control plot per site 10 Ailanthus trees per plot (>2.4 dbh) Plots are 20 X 50 m (66 x 164 ft)

23 Summary of percent cover vegetation at each of the five study areas within 2 x 5 meter subplots prior to inoculation of Ailanthus trees with Verticillium wilt Vegetation type Mean ±SEM A. Native plants Grasses % cover Native vines/lianas % cover Herbs & forbs % cover Shrubs - Spicebush % of plots Tree seedlings % cover B. Non-native plants excluding Ailanthus Japanese stiltgrass % of plots Japanese honeysuckle % of plots Garlic mustard % of plots Multiflora rose % of plots Bush honeysuckle % of plots Other non-natives observed include privet, periwinkle, wineberry, and autumn olive

24 Biweekly Disease Severity Index Ratings Score Description 0 healthy foliage 1 chlorosis and/or necrotic margins on leaves slight wilt (<15% wilting foliage) with no or slight 2 defoliation (<15%) moderate wilt (15 to <50% wilting foliage with no or 3 slight defoliation (<15%) severe wilt (50 to 100% wilting foliage with no or 4 slight defoliation (<15%) 5 moderate defoliation (15 to <50%) 6 severe defoliation (50 to 90%) very severe defoliation (90 to 100%) with epicormic 7 sprouting 8 dead

25 Ailanthus trees (>2.4 in dbh) 108 days after inoculation Percent of Forest Site Mean dbh (in) Max dbh (in) Mean Disease Rating trees (dead or >90% defoliation) Blue Rock SF Marietta WNF Perry SF Tar Hollow SF The Wilds Mean Controls (sterile water) *DAI = Days after inoculated with Verticillium fungal spores

26 The work continues Alternate ways to culture fungus Fungal inoculum has short shelf life Infected wood chips to inoculate Ailanthus Assess off-target effects

27 Studying off-target effects In PA: natural infections of V. nonalfalfae fungus were observed Striped maple (3%) Staghorn sumac (16%)

28 Devil s Walkingstick, Aralia spinosa PA - 17% were naturally infected Isolated fungus from leaves 2015 began trial inoculations of aralia & sumac in OH Credit: David Byres, Florida State

29 Devil s walkingstick 5 weeks posttreatment: all defoliated and spreading 52 weeks: top-killed but vigorously sprouting Sumac staghorn, winged, & glossy Limited symptom development Possible native hosts for fungus? Muskingum Watershed Conservancy District, Leesville, OH

30 Family Araliaceae - Mostly tropical shrubs and trees USDA PLANTS Database - 18 Genera and 47 species Devils walkingstick English ivy Schlefflera (Umbrella plant) Ginseng - 4 species American ginseng, Panax quinquefolius L. Credit: Gary Kauffman, USFS

31 Monitoring ginseng in current inoculation research plots 2016 Inoculated Ailanthus trees within ginseng areas Directly inoculated ginseng at 2 sites: moist & dry

32 THANKS OSAF & Ohio forestry community ODNR Division of Forestry, Wayne NF, & The Wilds Penn State & WVU - Don Davis, Matt Kasson, & Eric O Neal US Forest Service State & Private Forest Health Biological Control Program and NRS for financial support

33 SPECIAL THANKS FOR FIELD AND LAB ASSISTANCE Joan Jolliff, Tim Fox, Bill Borovicka, Dave Runkle, Jill Barber, Danielle Flowers, Andrew Hendricks, Joel Metelko, Laura Stevens, and Hagmel Vega-Fontanez

34 QUESTIONS? Joanne Rebbeck