Peach leaf curl is a fungal disease that attacks peaches and nectarines, and sometimes almonds, apricots and ornamental Prunus trees. As part of its scientific name suggests (deformans), it produces very deformed, distorted, crumpled and thickened leaves. Affected leaves also produce blisters, which are red at first, turning white later on as a bloom of fungal spores develops.
Diseased leaves tend to fall off the tree rapidly and prematurely, causing severe defoliation. This leads to a reduction or loss of the crop that year and, if trees are affected year after year, a gradual decline in overall health and a loss of vigour, resulting in much reduced crops.
Although peach leaf curl mainly attacks the leaves, stems and fruit may also be affected.
Disease attacks start in spring as the new leaves are unfurling and enlarging, and cool and wet conditions are needed at this time for infections to occur.