Eriophyid mite

Eriophyid mites are microscopic arachnids that feed on pine, fir, and other conifer foliage in Western Washington, causing discoloration, distortion, and abnormal growth of needles. You will see affected needles appear stunted, curled, or develop unusual coloring without visible pest activity. Damage accumulates on new growth in spring and early summer. Heavy infestations can reduce tree vigor and cause branch dieback.

Most trees tolerate eriophyid mite damage without serious decline. No effective chemical control is practical for landscape trees. Maintain tree vigor through adequate watering and avoid drought stress that makes plants more susceptible. Prune out severely affected branches if damage is severe. Natural predatory mites and other beneficial arthropods usually keep eriophyid mite populations in balance without intervention.