Filbertworm

Filbertworm larvae bore into developing filbert nuts in the Puget Sound, feeding on kernel tissue and creating an entry hole at the shell. You will see infested nuts developing spots or showing early decay signs. In commercial plantings, damage can reduce yield and nut quality significantly. Detection requires cracking open nuts or waiting for obvious rot and kernel damage.

Harvest nuts promptly and remove them from beneath trees to prevent larvae from pupating in soil. Bury or compost fallen nuts deeply; do not leave them on the ground where larvae can complete development. Spray timing for chemical control is difficult since damage occurs inside the shell. Most home gardeners accept some nuts with worms as the cost of growing filberts without intensive management.