Peach Leaf Curl Plant Pathology Peach Leaf Curl Peach leaf curl has been a common disease problem this spring. This fungal disease causes peach leaves to appear puckered, thickened, and often reddish in color. Later in the season, upper surfaces of infected leaves turn gray.
Diseased leaves fall from the tree prematurely.
Fruit yields are often reduced because the tree's energy is diverted into forming new leaves. Infection occurs as buds begin to swell and open in the spring. Spores of the fungus, which overwinter on bark and buds scales, wash onto the young leaf tissue in wet weather and initiate infections. Peach leaf curl tends to be most severe when buds open and leaves expand during wet periods. Applying a fungicide now will not be helpful, since the damage has already taken place.