Potato gangrene

Tubers initially appear healthy with the fungus present as a latent infection, but damage due to rough treatment during lifting, grading or handling, or due to low temperatures, can activate the fungus to cause tuber rot or gangrene (particularly during storage). Initially this appears as small, round, dark depressions near wounds and at the eyes, which develop into black circular to irregular lesions and eventually become extensive dark brown to purplish cavities.