| Table: Diagnosis and Control of Spruce budworm | ||
| Pest Identification | Host Plants | Damage Symptoms |
| Spruce budworm Choristoneura fumiferana Family Tortricidae |
Balsam fir and white spruce are preferred hosts, other spruces, hemlock, and Douglas-fir can be fed upon. | New foliage is fed upon in any given year. Local infestations can occur annually for 5-10 years with prolonged
outbreaks resulting in trees with very thin crowns, dead tops and dead trees. Fresh damage has silk associated with the larvae. Silk is used to tie needles together and for larvae to string down on. |
| Monitoring | Control Options | Pesticides |
| Look for larvae and foliage symptoms (tied foliage and mined needles) from early May through late June. | Physical: This is difficult to accomplish since larvae are dispersed through the tree and protected by tied foliage. Biological: Bacillus thuringiensis var. kurstaki is effective against larvae. Chemical: insecticidal can be effective though they require direct contact with larvae. This can be difficult because larvae are often wrapped in silk-tied foliage. For individual large trees, stem implants can be successful. However, implants should not be used in successive years. |
Insecticidal soap Acephate Carbaryl Diazinon Malathion Permethrin |
| Description and Life History | ||
|
Description: Mature larvae are 20-22 mm long with a black head and a black thoracic shield . The body is yellow-brown with two rows of
paired whitish spots along the back. Larvae have 5 pairs of prolegs. Life history: Adults emerge in early July to early August and lay clusters of eggs on host needles. Larvae hatch in late summer and spin a silk cocoon or hibernacula under a bark scale or other protected spot where they overwinter. Larvae emerge in early spring and begin feeding on developing buds, male flowers or by mining old needles. Later larvae feed on developing new needles. Pupation occurs on the tree. | ||
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