Crops Affected: Apple, crabapple, hawthorn, mountain ash, and firethorn.
Symptoms: Infection on leaves and fruits leads to lesions, with lesions on fruit developing corky tissue and becoming scab-like over time. Fruit may become deformed and fail to develop.
Treatment: Synthetic or organic (sulfur or copper) fungicides applied in rotation to avoid resistance
Estimated Economic Impact: $39-145 million annually, which is the most economically destructive disease of apple.
