Timing is important. Once the current year's leaves become infected they cannot be treated. Diseased leaves show a thickened, puckered appearance with a pink-red color. Later in the season infected leaves turn gray and fall prematurely from the tree. Diseased fruits are distorted and seldom remain on the tree until harvest.
Trees weakened by disease are more susceptible to winter injury.
Prepared by Paula Flynn , Department of Plant Pathology Iowa State University , Ames, Iowa. This information subject to a usage policy .