1. OBJECTIVES OF INSECT DEFOLIATORS At the end of this section students should be able to: 1) Know the difference among polyphagous, oligophagous and monophagous defoliators. 2) Know the principles of detection, evaluation and management of defoliators. 3)Know the life history, economic importance and ecological impact of the following defoliating insects: (A) spruce budworm (B) gypsy moth (C) Douglas-fir tussock moth (D) Defoliators of the Southeastern U.S.

2. Defoliation damage by insects can easily be recognized from symptoms: Foliage thin or absent Frass “raining” from trees Sometimes webs are apparent Larva crawling up/down tree

3. Fall Webworm – Hyphantria cunea

4. Symptoms Leaf chewers – eat entire leaf and include the Pine sawflies, Gypsy moths, Spruce bud worm

5. Symptoms Leaf skeletonizers – eat soft parts or the epidermal layers – not the veins.

6. Symptoms Leaf miners – bore inside leaves, between The upper and lower epidermis. Includes, the Pine needle miners and the Aspen leaf miner

7. Blotch mines

8. Damage by defoliators Primary Damage – Trees are killed by defoliation or growth is reduced. Conifers – 1 severe defoliation can kill tree Deciduous trees – better able to stand defoliation

9. Damage by defoliators Secondary damage occurs when defoliated trees are weakened and subject to attack by secondary pests such as wood borers, bark beetles, or soil fungi – Armillaria spp

10. Defoliators – Taxonomic Groups Lepidoptera: Many insect species Includes Pine Butterfly, spruce budworm Gypsy moth, catalpa worms

11. Defoliators Hymenoptera- Sawflies Red Headed Pine Sawfly Loblolly pine Sawfly Oak slug sawfly

12. Defoliators – Coleoptera: Cottonwood Leaf beetle, June beetles, Elm leaf beetle, & the Locust leaf miner.

13. Generalized Host Range of defoliators Polyphagous - Many hosts, e.g. Gypsy Moth Oligophagous – Few Hosts, e.g. Spruce budworm Monophagous – one hosts, e.g. Larch casebearer

14. Population Dynamics: Sporadic - Periodic -

15. Spruce Budworm - Choristoneura fumiferana

16. Life Cycle

17. Spruce Budworm Larva

18. Adult Moth

19. Spruce Budworm egg mass on needle

20. Spruce budworm 3 rd Instar in bud

21. Instars 4-6 feed on new foliage first and move to older foliage if necessary.

23. Populations are cyclic with peaks roughly every 8-10 yr. Major outbreaks every 60 years or so that corresponds with maturation of Balsam fir stand.

24. Management Considerations: Stand Composition- Chemicals- Biologicals-

25. Budworm Treated area to left of road

26. End of Spruce Budworm Section