Broccoli is somewhat more resistant, and radish is usually highly resistant. The first symptoms are usually yellow V-shaped lesions at the leaf margins. As the diseased area of the leaf expands and turns brown, the leaf veins in the affected area may appear black. Eventually, the leaf collapses. The pathogen may enter the stem and spread to all parts of the plant through the vascular system.
Infected stems show a ring of black discoloration when cut near the soil surface.
Remove infected plants. Remove any plant debris. Fall tillage will help reduce the overwintering pathogen population. Plant crucifers where air and soil drainage is good. Avoid overhead irrigation if possible or water early in the day.