What's eating my western larch?

Western Larch faces serious defoliation from the larch casebearer and western larch sawfly. Larch budmoth causes periodic needle-skeletonizing outbreaks. Douglas-fir beetle and other bark beetles exploit fire-damaged or drought-stressed trees. Bears occasionally strip bark to feed on sapwood. Healthy trees typically recover from a single defoliation year.

Needle tips mined and killed by larvae inside portable cases; browned scorched appearance across crowns; repeated attack causes growth loss and dieback of upper crown Spinosad or carbaryl applied as larvae become active in spring; biocontrol with Agathis pumila parasitoid wasp where established; single-season attacks tolerated by mature trees

Gregarious larvae strip needles in summer leaving bare branches; successive-year defoliation reduces radial growth and kills tops; frass visible beneath trees Bt or spinosad targeting early instar larvae; hand-remove small colonies on ornamental plantings; outbreak populations typically decline naturally after 2–3 years

Pitch tubes on bark; S-shaped larval galleries under bark; sapwood staining; branch and whole-tree death following fire injury or prolonged drought stress Salvage fire-killed and windthrown timber promptly; maintain tree vigor through site-appropriate planting; avoid unnecessary bark wounds; no spray recommended in forest settings