Rings develop and leaves may drop. Not prevalent in coastal areas. Plant early and fertilize. Avoid overhead watering. Clean up refuse after harvest.
Stems show dark brown or black discolorations.
Dispose of infected plants in the garbage immediately. Brown to black water-soaked spots on leaves and stems. Foliage will turn black, a gray mold grows on the undersides of the leaves and tubers will rot. Avoid overcrowding of plants. Dispose of infected plants in the garbage immediately.