A properly pruned open tree canopy has better air circulation which allows for faster drying of leaves and reduction of the number of infections. Because the apple scab fungus overwinters in apples and leaves on the ground, raking and removing fallen leaves and apples is recommended. Selection of high quality, disease resistant varieties is desirable since there are differences in susceptibility. Fungicides can be used to protect scab susceptible crabapples. Sprays need to be applied when growth first appears and repeated at 7 to 10 day intervals.
Thorough coverage is essential.
Follow label directions. Prepared by Teresa Cotten , Department of Plant Pathology Iowa State University , Ames, Iowa. This information subject to a usage policy .