| Powdery mildew fungus overwinters in terminal buds, which open later than surrounding healthy buds in the spring. The fungus affects leaves, green shoots, flowers, and fruit. Symptoms first occur as white or gray lesions on infected leaves and shoots early in spring. New leaves and shoots are more susceptible than older growth. Infected leaves fold longitudinally, are abnormally narrow, and become brittle. Infected flowers open late, and are greenish-brown with white fungal growth, and are shriveled. Fruit can be stunted and russeted by the fungus. |
Powdery mildew stunting and russetting on fruit. |
