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Past Articles Library | Plant Diseases & Control | Peach Leaf Curl

Peach Leaf Curl is a fungus that produces distinctive reddish blisters, which spread and cause affected leaves to curl and look distorted, thickened and swollen. Fruit may develop reddish areas or corky skin and trees may decline.

The leaf curl fungus survives the winter underneath bud scales and in other protected areas as resting spores called conidia. In the spring, conidia are moved by splashing water to newly developing leaves where infection occurs. The fungus grows between leaf cells stimulates them to divide and grow larger than normal, causing swelling and distortion of the leaf. Red plant pigments accumulate in the distorted cells. Cells of the fungus break through the surface of distorted leaves and produce another type of spore, called ascospores, that give the leaf a powdery or felt like appearance. Development of leaf curl stops when young tissue is no longer developing or when temperatures are above 80°F.

Peaches and Nectarines.

Parts of leaf or entire leaves become thickened, swollen, and distorted, and curl down and inward. Affected leaves have a purple or reddish color, later turning reddish yellow or gray. Swollen areas turn powdery gray as the fungus produces spores. Later, leaves turn yellow or brown and drop. Blossoms and young fruit may be attacked and usually drop early in the season. The current year's twigs may also be attacked and stunted; in severe infections, twigs may be swollen as well. The disease is worst in years with cool, wet spring conditions while tissue is still young and susceptible; older tissue is more resistant to infection.

Organic Control: Plant resistant cultivars such as 'Red Haven' Peaches. Maintain vigorous trees. Spray with Neem Oil.

Pick and destroy all affected leaves as soon as symptoms are visible to prevent fungus from reproducing; spray liquid seaweed extracts on remaining leaves at least once a month all season.

Other Controls: Spray with lime-sulfur, copper, or Bordeaux mix after leaves have dropped in the fall, and again in early spring at the times buds begin to swell.