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. Pussy willow is especially prone to attack. No control is usually necessary. Stems of goldenrod have high numbers of galls.