Peach Leaf Curl in the Home Fruit Planting

Symptoms

Infected leaves, which begin appearing in mid-May, are easily distinguished from healthy leaves because they are curled, puckered, and thicker than normal. Deformed areas are red to yellow at first and then turn brown. The infected leaves eventually fall from the tree.

Disease Cycle

Spores of the leaf curl fungus overwinter on the surface of peach twigs and buds. In spring, the spores multiply during periods of moist weather until the leaf buds swell and open. Rain is necessary for infection. The spores are carried on a film of water into the buds, where leaves are infected. Cool, wet weather slows leaf development and allows more time for leaf curl infection. Periods of cool, wet weather during bud development favor leaf curl development. Infection occurs readily at 50° to 70°F. Dry weather during bud swell and bud break limits leaf curl infection.

After the deformed and discolored leaves turn brown and fall, they produce powdery gray spores. These are blown by winds to peach twig surfaces and remain there for the winter.

Disease Management

Peach leaf curl is not difficult to control. A single fungicide application, made in the fall after the leaves have dropped or in the spring before bud swell, will control the disease. The spring application must be made before bud swell. Once the fungus enters the leaf, the disease cannot be controlled. Use products with active ingredients such as copper, sulfur, or chlorothalonil.

The fungicide kills the spores on twig and bud surfaces. For either the spring or the fall spray to be effective, application must be thorough and all leaves must be off of the trees. Complete coverage of the twigs, branches, and trunks is essential.

Secondary infections do not occur after the initial infections. The disease does not spread later in the season.