One of the worst diseases of peaches and nectarines, peach leaf curl is most active during rainy, cool springs. The spores of the fungus Taphrina deformans overwinter on a tree's bark, having been carried there by wind or rain; in spring, rain carries the spores to developing leaf buds. New leaves are puckered, curled, abnormally thick, and dotted with reddish blisters; entire leaves may turn red or yellow. Later in the season, powdery grayish white spores form on leaves, then blow onto bark and growth buds, setting the stage for the next cycle. Fruit may be entirely absent; if present, it is misshapen and may drop before it ripens.
To prevent peach leaf curl, plant resistant trees. Do a thorough fall cleanup and remove all debris from the ground below trees. Spray with sulfur or lime sulfur during the dormant season; timing is critical, so check with your Cooperative Extension Office for the best spraying dates. If you grow dwarf varieties, you can control the infection by covering trees with plastic sheeting during rainy weather in spring.
There is no chemical control.