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Pine Bark Adelgid

Pineus strobi[3]

Pine bark adelgids are tiny insects that cover the bark of pines and spruce with white, cottony wax; heavy infestations look like snow on the trunk.[1]

Group
Insect
Order
Hemiptera
Family
Adelgidae
US records
21 states
Sources
3 cited
Updated
2026-10-15
White cottony tufts of pine bark adelgids on a pine branch
White cottony tufts of pine bark adelgids on a pine branch. Photo: Lynn Harper, public domain (CC0), via iNaturalist
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. More from Iowa State Extension
  9. Related profiles
  10. Common questions
  11. Sources

How to identify it

  • They're about 0.03 inch long, black and short-legged under the white woolly wax.[1]
  • White cottony masses appear on trunks, branches or twigs; on seedlings and young trees they may sit at the needle bases or on shoots instead.[1]

Look-alikes

Look-alikeHow to tell them apart
Woolly aphidsPine bark adelgids look woolly and may be confused with woolly aphids.[1]

Where it lives

The PNW Insect Management Handbook covers it on pines and spruce in Pacific Northwest landscapes.[1]

US map: public records from 21 states since 1990 (GBIF).

Biology and life cycle

It overwinters as an immature insect on the tree and covers itself with waxy tufts as the weather warms.[1]

Small clusters of eggs are laid in the tufts in early spring; crawlers move over the tree or are blown or carried to other hosts.[1]

Damage and signs

  • Needles often turn yellowish, and severe infestations can stunt or kill trees.[1]

Health risk

It feeds on plants; the PNW Insect Management Handbook mentions no risk to people.[1]

Control

Prevention

Before budbreak, check shoots, trunk bark and branch undersides for white cottony insects, and look for natural enemies.[1]

Sanitation

Where practical, remove and destroy heavily infested branches and trees.[1]

Traps and physical control

Wipe small infestations off by hand or with a stiff brush, or wash them off trunks and foliage with a strong stream of water.[1]

Biological control

Encourage lady beetles and lacewings, and check colonies for live adelgids or crawlers before acting.[1]

More from Iowa State Extension

It occurs across the eastern U.S. on white, Scots and Austrian pines; healthy, established trees seldom need spraying, though small, newly transplanted or stressed trees can suffer.[2]

Common questions

What is the white fuzz on my pine trunk?
Likely pine bark adelgids, tiny insects that cover themselves with white cottony wax.[1]
Can pine bark adelgids kill a tree?
Severe infestations can stunt or kill trees.[1]

Sources

  1. Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Pine (Pinus): Pine bark adelgid (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/pine-pinus-pine-bark-adelgid (accessed 2026-10-06)
  2. Iowa State University Extension and Outreach, “Pine Bark Adelgid.” yardandgarden.extension.iastate.edu/encyclopedia/pine-bark-adelgid (accessed 2026-10-15)
  3. iNaturalist, “Pineus strobi taxon page (order and family).” www.inaturalist.org/taxa/228144 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.