Often spots will increase in size and form a large brown area. Do not irrigate late in the evening and try to avoid splashing soil on foliage. This fungal disease creates a white powdery mold on the upper leaf surface. In severe cases the new growth may be distorted. Early detection of this disease is very important.
Heavy infestations are difficult to control.
Botrytis is perhaps the most common fungus causing this problem in the home yard. If Botrytis is the cause of the blight, a grayish mold will cover the dead parts. Botrytis is most severe in cool moist weather. Preventative sprays of benomyl, chlorothalonil or zineb on a weekly schedule can be used. Remove decayed plant parts and debris to help minimize future infections.