What's eating my douglas fir?

Douglas Fir is threatened by the Douglas-fir beetle and western spruce budworm — two pests that have killed millions of acres of trees. Cooley spruce gall adelgid causes distinctive galls, while woolly aphids coat needles. Deer and elk browse young seedlings. Stressed, dense stands face the greatest risk from bark beetle attack.

Larvae consume new needles and buds in spring; repeated defoliation for 5+ years kills trees; crowns appear brown and ragged after each outbreak season Aerial Bt sprays targeting young larvae in spring during outbreak events coordinated by forestry agencies; spinosad as alternative; single defoliation events rarely lethal alone

Mass attacks on weakened or fire-damaged trees; S-shaped galleries under bark; blue-stain fungus inoculation kills cambium; crown turns red then grey; tree death within months Remove and salvage wind-thrown and fire-damaged trees promptly; thin overstocked stands to reduce competition stress; pyrethroid bark sprays for high-value ornamental specimens

Pineapple-shaped galls at branch tips in spring; galled shoots die beyond the gall; white waxy woolly masses on needle undersides; mainly cosmetic on mature trees Horticultural oil in late dormancy targets overwintering females; prune and destroy galls before adults emerge in summer; insecticidal soap on active woolly stage

Browsing of young seedlings and saplings removes leaders and foliage; antler rubbing strips bark from stems up to 1.5 m; kills or deforms young trees Tree tubes or wire guards around seedlings; deer fencing for nursery areas; repellent sprays need frequent reapplication; plan for deer pressure when spacing plantings