Identify, Prevent, and Treat Common Cabbage Diseases

Cabbages can fall victim to an array of diseases from all of the major classes of pathogens – fungi, water molds, bacteria, and viruses.

The infections can range in severity from the unsightly but not usually fatal, such as powdery mildew, to the almost uniformly fatal bacterial soft rot.

Some of these pathogens live in the soil where they can readily attack the roots of your crop, and many others lurk in the cruciferous weeds growing nearby.

We link to vendors to help you find relevant products. If you buy from one of our links, we may earn a commission.

Read on to learn about the many diseases that can affect your cabbage crop, and steps you can take to prevent or control them.

Alternaria leaf spot is caused by two species of fungi, Alternaria brassicicola and A. brassicae.

Both species are well known for causing leaf spots to develop on older tissue, but these fungi can also infect the base of the developing heads.

Alternaria is more likely to cause disease when moisture is present on the cabbage, and temperatures range from 68 to 81°F.

Symptoms include yellow spots that grow larger and develop rings around them like a target or bull’s-eye. As the tissue dies, the centers may fall out, resulting in holes in the foliage. As the disease develops, the spots join together to form large areas of dead tissue.

Controls for Alternaria leaf spot start with good cultural practices. These include the use of drip irrigation, sanitizing your gardening tools, rotating your crops, and removing all dead plant material at the end of the growing season.

Biopesticides that may prove effective in the case of an outbreak include Bacillus amyloliquefaciens and Bacillus