Symptoms
In midsummer, portions of terminal leaves turn red and start to pucker. Affected areas are thickened with a white to cream-colored layer of fungal spores underneath. The affected areas eventually turn black and dry up.

Disease cycle
Bushes are systemically infected and do not recover. Leaves on new growth from previously infected stems usually develop red leaf symptoms. Windborne spores are produced on leaf lesions in spring and summer and infect healthy leaves. The disease is favored by cool, moist conditions and excessive nitrogen use.

Management
Remove and burn infected bushes; use fungicides to protect healthy plants only if disease incidence is high.