Balsam Woolly Adelgid Adelges piceae

1. Balsam Woolly AdelgidAdelges piceae Presented by: Allison Kanoti

2. Balsam Woolly Adelgid • Reading http://www.fs.fed.us/r6/nr/fid/fidls/fidl118.htm

3. Introduction • Forest Management: Natural Regeneration • Tree Adaptations: Refer to SBW notes

4. IntroductionBalsam Woolly Adelgid • Introduced from Europe in early 1900’s • Susceptible Species: • True firs (Abies sp.) in North America

5. Tree Symptoms • 2 general types of infestation • Crown infestation • Stem infestation

6. Photo: Robert L. Anderson, USDA Forest Service www.forestryimages.org Tree Symptoms: Crown Infestation Gout Phase • swollen branch nodes • stunted terminal growth • Needle Mortality • Bud Suppression

7. Crown Infestation (Cont’d) • Crown thinning and Mortality • abnormal crown shape • prone to breakage

8. Tree Symptoms-stem infestation Trunk Phase • rotholz (rot=red, holz=wood) • Red-colored wood • Purple patches beneath bark • Broken, blocky bark

9. Diseased Functions • Tissues initially affected • Needles: mortality • Buds: suppression • Sapwood: uncontrolled, abnormal growth, poor water conduction • Impact on tree • crown deformity • dieback • predisposition to windthrow and root disease • death

10. Diseased Functions • Impact on Forest • dependent on climate, forest composition, site • loss of dominant and co-dominant fir component • change in species composition and age structure

11. Impact on Forest Maritime vs. Continental N.B. Characteristic Maritime Continental • All trees crown and stem infestations • Crown infestations persist w/ new growth • Small, isolated patches • Stem infestations on lower bole • Crown infestations checked by cold winters Infestation Pattern • Some large diameter trees killed by stem infestation • Low tree mortality • Most overstory trees killed or have dead tops Tree Mortality Regeneration • Some severely gouted and killed • Regeneration by stem infested trees gouted Source: Greenbank, D.O. 1970. Climate and ecology of the balsam woolly aphid. Can. Ent. 102: 546-578.

12. Diseased Functions:Impact on Forest “BALSAM WOOLY ADELGID INFESTATION SALVAGE HARVEST. . .”

13. Primary Stress Agent Balsam Woolly Adelgid -- Adelges piceae • Introduced from Europe ca. 1900 on nursery stock to Maine and Nova Scotia • On native silver fir does not cause significant damage • North American host trees: Abies spp.

14. Photo:Scott Tunnock, USDA Forest Service, www.forestryimages.org Photo: USDA Forest Service - Ashville Archives www.forestryimages.org Pathogen Signs • Eggs--up to 248 yellow eggs laid in waxy wool-like extrusions • Larvae--3 larval instars • Adult-- approximately .8 mm long, covered in waxy wool-like material Photo: Jerald E. Dewey, USDA Forest Service, www.forestryimages.org

15. Environment Host: True firs • balsam and Fraser in the east; sub-alpine, Pacific silver and grand in the west Native range of balsam fir (from silvics)

16. Environment Distribution of Balsam Woolly Adelgid From BWA FIDL 1970 East Coast West to east prevailing winds limit inland spread

17. Environment Moderate winters • Do not survive below -30º F • Snow and tree structures afford some protection from cold

18. Predisposing FactorsTree Adaptations Introduced Pest North American firs highly susceptible Site Productive • Washington State, Pacific silver fir • Johnson et al. 1963 Well drained to dry • Newfoundland • Page 1975 Poorly drained • Maine • Brower 1947

19. Predisposing FactorsTree Adaptations Age Related Factors • Initial infestations on larger trees • Taller • Deeper Crowns • Larger Diameter • More likely to have stem infestations • Ideal size around 30-40 years old • Rough barked trees more susceptible (more protected locations) • Younger, denser stands less susceptible

20. Predisposing FactorsDegree of Stress Life Cycle Components Impacting Degree of Stress • Eggs:average 100 eggs/female 1st gen (50, 2nd gen), some dispersal • Larvae: Crawlers: mobile stage, dispersal, overwintering • Adults: High reproductive capacity • Reproduction: parthenogenetic, no males necessary, no need for mate finding or successful mating • Multivoltinism

21. Break dormancy Late April, early May 2nd, 3rd instars, adult*, eggs, 1st instar (crawler) Eggs (June) From: F.P. Hain, 1988 in A.A.Berryman Hatch w/in several days No molt *2nd generation adults abundant late Sept; egg laying thru Mid-Nov. Predisposing Factors: Degree of StressLife Cycle (Maine: 2 generations/year) Overwintering Neosistens 2nd, 3rd instars and adult 1st Instar (Crawler) Neosistens

22. Predisposing Factors: Degree of StressMechanism of Disruption • Stem Infestation • change in water transport structures • development of rotholz • Reaction to chemicals in the insects’ saliva • Thick walled cells, wide rings • Similar to compression wood/heartwood • poor water conduction • physiological drought

23. Predisposing Factors: Degree of StressMechanism of Disruption Crown Infestation • change in wood structure (rotholz) • old needles not replaced • buds inhibited • loss of photosynthesizing capacity • gradual starvation

24. Predisposing Factors: Degree of StressPopulation Controls Weather • Early or late freezing temperature • 100% mortality of overwintering stage at -30ºF, • NB study, ~40% died w/ low T of -22 º F (~80% after 5 days of -22 ºF) • All other life stages die w/ prolonged temps <32 ºF, killed instantly @ -5 ºF • Cold winters with little snow cover • Warmer climates see more generations/yr.

25. Predisposing Factors: Degree of StressPopulation Controls Native Predatory Invertebrates/Introduced Predators • Native natural enemies • Predatory mites • Lacewings (occasional) • Plant bugs (Mirids) • Coccinellids • Syrphids • Most important natural enemy • Success limited by high level of parasitism • Introduced biological control • 3 Coleoptera • 3 Diptera http://photo.dipterologic.com/data/media/1/ skuznetzov_syrphus_torvus_DSC072345.jpg http://www.rutkies.de/kaefer/Aphidecta%20obliterata %20-%20Gebirgsmarienkaefer%2001.html

26. Predisposing Factors: Degree of StressPopulation Controls Native Predatory Invertebrates/Introduced Predators Issues • Generalist predators • Univoltine predators, multivoltine target • Do not feed on important life stages • Controls dependent on high adelgid populations • Cold tolerance of introduced controls • Introduced predators all adapted to feeding on stem infestations Ideal • Specialist Predator • Capable of surviving on low densities (and keeping densities low) • Capable of responding through increased fecundity or increased feeding rate to growth of prey populations • Capable of active searching and feeding • In diverse habitats (stem and twig) • On several life stages (esp. egg crawler) • Parasitoid (no known on Adelginae) http://cedarcreek.umn.edu/insects/ album/029083009ap.html

27. Predisposing Factors: Degree of StressPopulation Controls • Food availability and quality • After several years of infestation, changes in the bark structure can make individual trees temporarily unsuitable • Leads to decreased adelgid population • As cracks form, parenchyma is near surface • Again suitable for adelgid • Possible for insects to build up from low level populations on understory fir

28. Inciting Factors • Arrival of crawler on suitable feeding site • Insertion of stylet and change to neosistens (rotholz develops at this stage regardless of further survival of the insect)

29. Contributing Factors • Drought • Ice and wind damage • irregular crown shape contributes to predisposition to damage • Fungal Infection • root rots (which further predispose to windthrow)

30. Questions?

31. Your Questions: Based on your knowledge of the balsam woolly adelgid and of balsam fir : • describe preemptive control measures. • Describe reactive control options Justify your answers with supporting biological and ecological characteristics of the species