Peach leaf curl can be controlled with a single fungicide spray, but timing is critical. The fungicide must be sprayed in the dormant season, either after the leaves drop in the fall or before the buds begin to swell in the spring. With the recent warm weather, bud swell will be occurring soon. Some of the fungicides registered for control of leaf curl include liquid lime-sulfur, chlorothalonil, Bordeaux mixture, and other copper products. The fungus that causes peach leaf curl, Taphrina deformans, overwinters in bark crevices and bud scales of trees.
Spring rains wash the spores of the fungus onto the newly emerging leaf tissue.
Cool and wet conditions provide the best conditions for the fungus. If leaves become infected, they cannot be treated that year. Infected leaves will eventually turn a gray color and fall from the tree. Early leaf drop year after year can lead to a reduced fruit crop and predispose the tree to other stresses such as winter injury. Prepared by Paula Flynn , Department of Plant Pathology Iowa State University , Ames, Iowa.