Control of Peach Leaf Curl needs to be completed in the dormant season before any growth occurs. Once growth starts the new leaves are infected but the results of the infections appear a couple of weeks later. Here in coastal British Columbia, the most commonly used fungicide in gardens is Lime Sulfur in the late dormancy. Tribasic Copper Sulphate is also used in the late fall to reduce infection rates. Since this is a 60" rainfall area the best way to grow peaches and nectarines is under a rain shelter as this also eliminates peach leaf curl, Blossom Blight, and Coryneum Blight.
Horsetail tea can be applied year round to treat peach leaf curl - pick a cooler day and spray liberally in the morning.
