Bacterial soft is a very serious cabbage disease. The disease is caused by a bacterium (Pectobacterium carotovorum) that leaves in dead decaying plants in the soil. The bacteria gets into a cabbage plant through stomata (openings on the plant for breathing and transpiration), wounds caused by farm activities such as weeding or destruction by animals and cracks on cabbage mostly caused by very cold weather. Bacterial soft rot is a secondary disease of black rot and can lead to significant yield losses. Affected heads are also not marketable. The bacteria normally spreads through irrigation with contaminated water, insect transmission and use of contaminated tools in the farm.
The bacteria normally spreads through irrigation with contaminated water, insect transmission and use of contaminated tools in the farm.
Conditions for Development
- Cabbage wounds and injuries
- Moist conditions, a lot of rain or over-irrigation-
- Warm temperatures (24-28℃)
- Through transportation and poor storage conditions
- Primary diseases like black rot and blackleg
- Cabbages deficient of calcium.
How to Identify Bacterial Rot in Cabbages
- Observe the presence of water-soaked spots
- The spots enlarge and become soft
- Tissues under the spots are mushy and discolored
- A bad smell is present
- This confirms the presence of bacterial soft rot disease
How to Prevent or Control the Disease
- Cultural control methods
- Transplant seedlings in rows to allow good air circulation in the farm
- Be careful when working on the farm to avoid injuring the crops
- Avoid frequent overhead irrigation during head development (practice ground irrigation)
- Use materials such as paper to prevent injury to the head in storage
- Practice crop rotation with crops not affected by soft rot such as maize or any other cereals
- If a field is heavily infected by soft rot, consider planting non-host crops for at least three years to suppress the disease. During this period- do not plant cabbages, potato, carrot, tomato, cucumbers, melons, squash, pumpkins, cauliflowers.
- Remove diseased plants immediately and destroy them- do not compost them as the bacterial will spread again through the compost.
- Do not harvest when its wet and moist- only harvest cabbages when it is dry
- Wash hands and knives with sodium hypochlorite (10%) during harvesting you can also use a hand sanitizer.
- Avoid packing produce when wet
- Remove, destroy and burn infected crops and plant parts in the field after harvest
- Add bone meal to your farm to increase calcium content in the soil. You can also use lime if a soil test shows low levels of calcium in the soil
- Use a straw or other material in the store to prevent injury to the crops
- Properly inspect cabbages to ensure not to mix diseased heads with the rest after harvest
Can You Save Infected Crops?
Infected crops uproot and burn before the disease spreads to other crops. DO NOT bury the crops since the pathogen lives in the soil.
There is no treatment for Blackspot rot, however, there is research ongoing with promising results.
