Filbert Bud Mite
Phytoptus avellanae
2 host plants
Filbert bud mite feeds within filbert buds in Western Washington, causing them to become swollen, distorted, and fail to open properly in spring. You will see enlarged, abnormal buds that may crack open prematurely. Heavily infested branches produce few or no catkins and fail to flower. This mite can severely reduce nut production on commercial and home filberts.
No effective chemical control is practical for home gardeners. Remove infested buds by hand in late winter before they open; this is tedious but limits population growth. Prune out heavily infested branches. Improve tree vigor through proper watering and care; healthy trees can tolerate moderate damage. Some filbert varieties show resistance; consider replanting with resistant genetics if damage is severe.