If you have ever seen emerging peach leaves that are puckered, swollen, distorted and reddish-green color, you have seen peach leaf curl. Uncontrolled, this disease can severely weaken trees due to untimely leaf drop when leaves unfurl in the spring. Fortunately, peach leaf curl is not that difficult to control if the spray is applied early enough. However, by the time you see symptoms, it is much too late. As a matter of fact, fungicides are ineffective if applied after buds begin to swell. Don’t spray when temperatures are below 40 degrees or will fall below freezing before the spray dries. Usually we can wait until March to spray but an extended warm period in February that encourages early bud swell may require spraying in late February. Though peach leaf curl can be controlled by a single fungicide application either in the fall after leaf drop, it is more commonly controlled in the spring.
There are several fungicides labeled for this disease including chlorothalonil (Ortho Garden Disease Control, Fertilome Broad Spectrum Fungicide, GardenTech Fungicide Disease Control and Daconil). Thoroughly cover the entire tree during application. Note that it is much easier to achieve good spray coverage if the tree is pruned before spraying. (Ward Upham)
photo credit – Rubber Slippers In Italy