Filbert Aphid

Filbert aphids are small, soft-bodied insects that cluster on filbert buds, shoots, and leaves in the Puget Sound, causing curling and distortion of new growth. You will see yellowing leaves and stunted branch tips. Heavy populations may cause premature leaf drop. These aphids are particularly problematic in early spring when new foliage is emerging and vulnerable.

Spray insecticidal soap on new foliage as growth begins in spring, targeting aphid clusters before damage becomes severe. Strong water spray can dislodge aphids and reduce populations without chemicals. Encourage natural enemies including lady beetles, parasitoid wasps, and lacewings by preserving flowering plants nearby. Most filberts tolerate light aphid populations without serious impact. Avoid excessive nitrogen fertilizer, which promotes tender new growth that aphids prefer.