Douglas-Fir Needle Midges

How to identify it

• Adults are tiny, delicate-looking flies about 0.05 inch long.^[1]
• The tiny white larvae mine inside needles, which turn yellow and distorted and often bend sharply at the injury.^[1]
• Three different midges infest Douglas-fir: one feeds near the needle base, one near the tip and one near the middle.^[1]

Where it lives

The PNW Insect Management Handbook covers them on Douglas-fir in the Pacific Northwest, where they're most significant in Christmas tree plantations.^[1]

US map: public records from 2 states since 1990 (GBIF). View the map

Biology and life cycle

Midges pupate in the ground, and adults emerge around budbreak in spring to lay eggs on new growth.^[1]

Larvae mine the needles through summer, then drop to the ground at summer's end to pupate; there's one generation a year.^[1]

Damage and signs

• Damaged needles often drop, and heavy infestations can cause severe defoliation, though they're less of a problem in landscapes and wooded stands.^[1]

Health risk

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

Control

Traps and physical control

Prune out heavily infested twigs and branches.^[1]

Common questions

Why are new needles on my Douglas-fir yellow and bent?

Douglas-fir needle midge larvae mining the needles cause yellowing and sharp bends at the injury.^[1]

Are Douglas-fir needle midges a problem in yards?

Less so; they're most significant in Christmas tree plantations.^[1]

Sources

1. Pacific Northwest Pest Management Handbooks (OSU, WSU, University of Idaho), “Douglas-fir (Pseudotsuga): Douglas-fir needle midge (Insect Management Handbook).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/douglas-fir-pseudotsuga-douglas-fir-needle-midge (accessed 2026-10-06)
2. iNaturalist, “Contarinia pseudotsugae taxon page (order and family).” www.inaturalist.org/taxa/208526 (accessed 2026-10-06)