Hello! 

This is a fungal disease known as peach leaf curl.  Here is an article from our peach expert about the disease: 

https://www.growingproduce.com/fruits/stone-fruit/peach-leaf-curl-one-scary-disease/

For peach growers, the first spray of the year is to control “curl leaf” or peach leaf curl. Peach leaf curl is an important disease in Michigan. This disease can defoliate peach and nectarine trees. The fungus that causes peach leaf curl overwinters on the tree. Infections take place in the spring as the buds open. The fungus infects peach buds from bud swell to bud opening under wet conditions. Air temperatures between 50 to 70°F are ideal. Rain or dew moves spores into the opening buds, allowing the infection of young tissue. The disease requires about 10 to 11 hours of wetness for infection to occur. Prolonged cool wet periods during bud burst can result in severe infections.

Early spring applications at or before bud break are effective in controlling this disease. Late fall applications (50% or more leaf drop) are also effective.

Effective controls include Bravo, Ziram, Carbamate and copper compounds. Copper compounds have the added benefit of providing some suppression of bacterial spot as well.

Once leaves are infected there is no effective fungicide treatment. The leaves are infected in the bud. Infected leaves become crinkled, turning orange or red. The leaves become thick and powdery with spores as the fungus sporulates. Infected leaves eventually fall off. The tree will grow new leaves.

Peach leaf curl weakens the tree by removing leaves during early growth. This reduces energy the tree can absorb from the sun, weakening the tree, and reduces growth and fruit size. Heavy fruit thinning reduces stress on the tree and increases the likelihood of a marketable crop. Severely infected trees should receive an increased ration of nitrogen fertilizer. This will help the tree replace lost leaves and maintain vigor.