One thing that might work, other than using a chemical spray, would be to give the tree bark a wash in the fall after leaf drop.
If the solution used has a pH the fungi can not tolerate and a wetting agent (soap) it very possibly could remove the spores thus preventing a new spring outbreak.
The most successful means of treating leaf curl organically is spraying with a Trichoderma mix, which is a natural organic fungus which feeds on the other fungus. Whereas copper applications often defoliates the tree, Trichoderma will only attack the area where the leaf curl is on the leaf, the remaining section remains intact and continues to grow. Regular applications of Trichoderma can eliminate leaf curl completely. Trichoderma should be applied at leaf burst and then 2 or 3 times through the season. However as a living organic substance Trichoderma cannot be applied in conjunction with chemical applications.
The traditional gardener's method is to plant peach trees against a house wall under an overhanging roof, possibly covered by a mat during the winter, to keep winter rain from the buds before they burst (and incidentally to delay blossoming until spring frosts are over), until the temperature exceeds 16 °C (61 °F) in the spring, deactivating the fungus
George Hayduke wrote:My peach trees tend to drop leaves from a fungus in the mid to late summer. I just let them do it and don't treat for the fungus. In the spring the leaves come out healthy and stay healthy long enough to produce a crop of peaches.