Key Features
- Slight yellowing of the canopy
- Blisters/ abnormal leaf growth
- Fuzzy growth on blisters
Symptoms
Taphrina infected tissues grow more rapidly than un-infected tissues. This causes small, white, green, or yellow blisters to form on young leaves. The blisters enlarge, become discolored, and occasionally die as the leaf develops. One side of each blister is covered with a light, powdery fungal growth.
Biology
Cool, moist conditions are required for infection. Taphrina only infects young emerging leaf tissue in the spring. New spores are formed on the surface of the spots are blown to new buds where they remain dormant until the next spring. These spores stick to new leaves as they emerge. The fungus has only one infection period in the spring and does not continue to cause new spots later during the growing season.
Management Recommendations
Fungicide application is not necessary because the leaves are rarely severely spotted and do not drop early. Although infections may be extensive some years, little damage actually results. To prevent spotting, a fungicide must be applied prior to bud break. Chlorothalonil can be applied late in dormancy. Once bud break has occurred and symptoms are visible, it is too late to spray. Always read and follow the directions on the fungicide label.
Effective Pesticides
Active Ingredients include: Chlorothalonil
Resources
- Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
- Sign Up for the Purdue Landscape Report
