Horticultural and Marketing Agent Deformed peach leaves with leaf curl. Peach leaf curl is an infrequent but occasionally severe disease of peach and nectarine. The pathogen infects peach buds from bud swell to bud opening under wet conditions and air temperatures in the 50 o to 70 o F range.
Infections can take place in the spring from bud swell to bud opening.
Copper compounds have the benefit of providing some suppression of bacterial spot as well. Bravo has been rumored to help suppress Cytospora canker. But, there is no data to support this. The key to good disease control is early spring applications of materials that suppress fungal growth as the bud opens. These sprays need to be made before rain washs the overwintering spores into the bud.