They deform the branches. Cut and burn all twig galls before the first of March. Insecticide spray may do more harm than good by killing beneficials. Found on the elm leaves. Treat with malathion or horticultural oil before the buds open.
Galls are about the size of large hickory nut, cone-shaped and found one to a twig at the very tip.
Treat with malathion or horticultural oil before the buds form. Occurs on stems usually about 2 inches in diameter. Gall consists of a mass of brown, moss-like filaments covering a hard kernel. Prune, remove, and burn the infested parts of the plant. Gall is large and oval-shaped and develops on lower shoots.