The damage can be confused with frost injury. Prune out infected twigs and spray in early spring with an approved fixed copper fungicide. Mainly a nursery disease. Large, rough, woody swellings or galls on the lower part of the stem and crown of the plant. Infected plants may be deformed, stunted or even killed.
Weeping willow is susceptible.
No practical control is known for this disease. Discolored, sunken, often sharply defined areas develop on twigs, branches or trunk. Cankers enlarge and gradually girdle infected parts causing death to portions beyond. Weeping willow is susceptible, but rarely occurs on black willow. Prune out and destroy dead and cankered parts.