Peach Leaf Curl Description: : Leaves become thickened and curled or crinkled, and turn yellowish or reddish. Later, diseased leaves and misshapen fruit fall off tree. Solution: Spray with Soap-Shield® Fungicidal Soap, ensuring that all surfaces are thoroughly sprayed. Apply as a dormant spray (after leaves have fallen) in late fall. Alternatively, Bordeaux Mixture may be used after leaves drop in fall and again in spring before buds open.