The white spots are produced by the fungus mycelium and its spores. Later the mycelium sloughs off and leaves a rusty-colored patch with dead epidermal cells. About the time of pit-hardening, the skin of the fruit under the spot turns pinkish, and the fungus and its spores disappear. Eventually the skin becomes leathery or hard, turns brown, and may crack. Diseased leaves often fail to unfold normally, while those of new shoots become narrow, straplike, and distorted.
New shoots are shorter than normal and distorted.
The white mycelium and spores of the fungus may cover infected leaves and shoots or may appear as whitish patches. The fungus overwinters in dormant peach buds. Flower buds of infected shoots often do not survive the winter. As leaf buds expand in spring, young leaves become infected and the spores produced on the leaves serve to infect young fruit, new shoot growth, and newly expanding leaves. Leaves are susceptible to infection when young but become resistant as they age.