Powdery mildew appears as superficial, white powdery growth on leaves and shoots that results in the stunting and distortion of young growth. Right: ruit like this Jonathan apple, when infected with powdery mildew, are stunted and russetted, and fruit set may be reduced. A good year for apple scab is usually a bad year for powdery mildew, and vice versa. Apple scab thrives under cool, damp conditions, while powdery mildew likes hot, dry weather. But the two apple diseases develop about the same time, early in spring, and coexist, with weather determining which will be the more severe ­problem. In […]