Soft Rot on Cabbage
Emily Zobel, Ag Agent, University of Maryland Extension - Dorchester County and Neith Little, Urban Ag Agent, University of Maryland Extension - Baltimore City
Bacterial soft rot can be caused by multiple species of bacteria, including Pectobacterium carotovorum and Dickeya dadantii. Infection is most common when conditions are wet and warm. Numerous vegetable crops are susceptible to this disease, including cabbage, broccoli, onion, potatoes, pepper, melon, cucumber, bean, and beet. Soft rot has been observed in cabbage this fall.
The bacterium enters host plants through growth cracks or wounds. Under warm, humid conditions, uninjured tissue may become infected through natural openings. Prolonged moisture from rain or irrigation and mild temperatures encourage disease development. Once inside the bacteria will then break down the plant’s structural molecules, causing the plant tissue to collapse and rot.
On cabbage and other leafy brassica, symptoms include water-soaked spots on outer leaves, which will become larger areas of wet, necrotic tissue. Inside the head, tissues become mushy and discolored with a foul odor. On broccoli and cauliflower, parts of the head will have a wet appearance at first. Then as the disease progresses they become brown sunken necrotic patches.
There are several management strategies that can be utilized to reduce soft rot issues.
- Start with disease free seed and transplants and rotation with crops such as corn, small grains, or alfalfa.
- As bacteria thrive in wet environments, management of irrigation can be impactful in preventing soft rot. Avoid waterlogged soils. Utilizing drip irrigation or soaker hoses will reduce leaf and produce wetness.
- It is important to reduce wounding during planting, cultivation, harvesting, and subsequent transport. Harvest only during dry conditions. Store and ship produce in clean, dry, and cool conditions. Hold plants at 39 to 45°F to minimize spread following harvest.
- The pathogen overwinters in infected tissue, farm implements, and plant debris. Remove and destroy all plants displaying symptoms of bacterial disease. Composting these plants will only allow the bacteria to persist in the next growing season.
This article appears in October 2026, Volume 17, Issue 9 of the Vegetable and Fruit News