Symptoms and Signs
Bacterial blight infections start as small, angular-shaped, water-soaked specks on leaves that are often surrounded by yellow borders. As the disease develops, specks enlarge and coalesce together into larger, irregularly shaped gray-to-tan spots. Leaf spots are visible from both top and bottom sides of leaves. Symptoms may resemble those of the more familiar bacterial leaf spot disease.
Comments on the Disease
Recent research has identified this bacterial disease, which is caused by a pathogen related to, but distinct from, the bacterium that causes bacterial leaf spot. For cole crops, bacterial blight has been found on broccoli, cauliflower, and Brussels sprouts. Other crucifer hosts include rapini, arugula, and rutabaga. The pathogen is seedborne and is splashed from plant to plant by rain and sprinkler irrigation. Bacterial inoculum may persist for short periods of time in soil.
Management
Plant clean and disease-free transplants. Rotation away from fields where the disease has recently occurred may reduce inoculum levels in soil or infected debris. A change from sprinkler to furrow or drip irrigation may limit its spread.