One problem showing up in landscapes is a canker disease causing wilt and dieback on rhododendron, caused by the fungus Botryosphaeria dothidea.
The first indication of a problem usually is the appearance of individual stems with drooping, wilted-looking leaves that are rolled inward. The wilt symptom may spread until the whole plant is affected. Closer examination of affected stems reveals a reddish-brown to black sunken canker that girdles the stem. Cankers develop slowly and may appear a month or two after infection. This disease is more likely to occur on plants suffering from heat and drought stress or winter injury. Thus, recent hot, dry weather may have stressed Rhododendrons creating conditions favorable for canker-causing fungi such as Botryosphaeria.