Infection occurs during the spring just as the buds begin to swell. Spring rains wash spores of the fungus to newly emerging leaf tissue. Cool, wet conditions favor the disease. Once the current year's leaves become infected, they cannot be treated. Fortunately, the disease is fairly easy to prevent with a single fungicide application.
Timing is critical.
Because infection occurs when the buds begin to swell, the fungicide must be applied during the dormant season, either after leaf drop in the fall or in late winter before buds begin to swell. Fungicides effective for control of peach leaf curl include liquid lime- sulfur, Bordeaux mixture, and chlorothalonil. Branches and twigs must be covered thoroughly for effective disease control. Prepared by Paula Flynn , Department of Plant Pathology Iowa State University , Ames, Iowa. This information subject to a usage policy .