Highlights Peach Leaf Curl Peach leaf curl is caused by the fungus aphrina deformans . This disease of peach and nectarines is easy to identify.
Young leaves appear thickened and puckered and are often a pink or red color.
The entire leaf may be affected or only small areas. As the disease progresses, leaves turn a gray color and fall prematurely from the tree. Trees that are severely defoliated may not yield well and are predisposed to winter injury. The fungus that causes peach leaf curl overwinters on bud scales and twigs. When buds open in the spring, the fungal spores come into contact with the newly expanding leaves.