The fungus that causes peach leaf curl, Taphrina deformans, overwinters on buds scales and twigs. 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. Fortunately, the disease is fairly easy to control 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. Once the current year's leaves become infected, they cannot be treated. Prepared by Paula Flynn , Department of Plant Pathology Iowa State University , Ames, Iowa. This information subject to a usage policy .