It is typically associated with moist weather. Under disease conducive conditions infection can result in defoliation and fruit loss. Leaf curl is one of the easier diseases to identify. Infected leaves appear blistered, distorted, and may occasionally be coated with a white-grey coating. Fruit infection is characterized by small red lesions .
Infections typically occur during early spring between bud swell until leaf emergence.
The disease is most under the slow drying conditions prevalent during cool, rainy weather . Warm weather during early spring suppresses disease development. The grey white coating on infected leaves represent millions of fungal spores known as conidia. These spores are blown to areas on the tree where they will survive the upcoming winter. Leaf curl is controlled by copper sulfate, fixed copper, chlorothalonil, or ziram, applied with dormant sprays .