Black rot, a disease caused by the bacterium Xanthomonas campestris pv. campestris, often causes V-shaped lesions (wounds) along the leaf edges. Infections begin at the leaf margins, causing yellow V-shaped spots; veins near the spot become dark as the bacterium spreads within the plant. Stunting and wilt become increasingly severe with time.
There are no chemical controls for this disease. Choose varieties tolerant to black rot. Use crop rotation in the garden; buy only certified disease-free seed and transplants; and avoid working plants when wet. Remove and destroy infected crop debris.
