The leaves have red, curled, and distorted areas. The bacterium Xanthomonas pruni causes leaf spot and twig cankers on cherry. Small, reddish spots dry, and drop out, giving a shot holed appearance.
Defoliation can be severe when conditions favor disease development.
Fertilize infected trees and prune out infected branches. Coccomyces hiemalis causes reddish spots which drop out leaving shot holes. Once the holes appear the leaves may drop. The disease is worse in wet weather. Black knot causes black swellings or galls on the branches.