How to identify it
Where it lives
The PNW Insect Management Handbook calls it a serious forest pest and common in landscapes on balsam, grand, subalpine, Pacific silver and Fraser firs.[1]
Biology and life cycle
All are wingless females, immobile except as crawlers, which the wind carries from tree to tree.[1]
Eggs are laid on the bark, and there are two to four generations a year.[1]
Balsam fir and subalpine fir are particularly susceptible.[1]
Damage and signs
- Infestations weaken trees, thin the foliage and can kill trees; heavy ones may cover the whole trunk.[1]
Health risk
It feeds on plants; the PNW Insect Management Handbook mentions no risk to people.[1]
Control
Traps and physical control
On smaller trees, wipe or brush off minor infestations, or hose trees with a strong stream of water.[1]
Biological control
Small lady beetles and their wax-covered black larvae, plus syrphid fly larvae, feed on it; avoid broad-spectrum insecticides.[1]
More from NC State Extension
Fraser fir suffers most of all the firs and dies after several years of infestation; the adelgid is largely responsible for the decline of native Fraser fir stands in the southern Appalachians.[2]
Common questions
Sources
- Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Fir (Abies): Balsam woolly adelgid (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/fir-abies-balsam-woolly-adelgid (accessed 2026-10-06)
- NC State Extension, “Balsam Woolly Adelgid.” content.ces.ncsu.edu/balsam-woolly-adelgid (accessed 2026-10-15)
- iNaturalist, “Adelges piceae taxon page (order and family).” www.inaturalist.org/taxa/199321 (accessed 2026-10-06)