Leaves are puckered, thickened, and curled from the time they first appear in the spring. Emerging shoots are swollen and stunted. Infected foliage is discolored. A grayish white powdery material develops on the leaves, which shrivel and drop. Fruiting is poor, and the fruit that is present may be covered with raised, wrinkled, irregular lesions.
Infected leaves cannot be cured. Spray trees with a fungicide labeled for this disease, following label directions.