Crown gall is usually found at or near the soil level and appears as rough-shaped, hard or soft, spongy swollen tumors. The color of the galls varies from flesh-colored to greenish or dark. Where this gall is discovered, it is best to discard the plant altogether. A few galls on a tree or plant seldom warrant control. They may be hand picked and discarded.
Most galls are difficult to control since insect life cycles vary so much.
A spray of malathion in mid-April and early May will often reduce the incidence of a wide variety of galls on many of our common trees and shrubs.