Disease Management

turnip soft rot
turnip mosaic virus

Bacterial Soft Rot (Pectobacterium carotovorum)

Causal Agent

Bacterial soft rot is caused by the bacteria Pectobacterium carotovorum. It affects many vegetable crops including brassicas.

Symptoms

Water-soaked lesions on foliage develop early in the season. Cabbage will develop an internal mass of macerated tissue. Slime will ooze from cracks or other openings. Broccoli and cauliflower heads become brown and sunken.

Disease Cycle

It is spread by splashing water, various insects, and pruners and other equipment. The disease thrives in a warm and humid environment. Bacteria enter through plant wounds and can survive in plant debris left in the garden. Bacterial soft rot may also develop within stored produce.

Management

  • Decontaminate knives or other tools used when harvesting and moving from plant to plant.
  • Remove cull piles near production sites. Plant debris can harbor bacteria and be a source of infection.
  • Ensure soil is well-draining. High moisture increases the spread of bacteria
soft rot
cabbage soft rot

Turnip Mosaic Virus

Causal Agent

Turnip mosaic virus (TuMV) is a plant pathogenic virus belonging to the Potyvirus genus and is primarily transmitted by aphids. This virus can infect a wide range of Brassica spp. crops causing significant damage to their growth and yield.

Symptoms

Mottled leaves appear with a characteristic light and dark green mosaic pattern, yellowing, stunted growth, and leaf distortion. Severe cases may also exhibit necrotic areas and reduced yields.

Disease Cycle

Aphids serve as the vector and acquire the virus when they feed on infected plants. They subsequently transmit the virus to healthy plants during feeding, leading to infection. The virus multiplies within the host, causing characteristic symptoms, and infected plants serve as sources for further transmission by aphids. TuMV can also survive in plant debris and weed hosts.

Management

  • Use resistant varieties. Source plant cultivars that are labeled resistant to tolerent of TuMV.
  • Practice sanitation. Practicing good sanitation is essential. Remove and destroy infected plant material to prevent the virus from persisting in the field. This includes not only the main crop but also any nearby weeds that could act as reservoirs for the virus.
  • Control aphids. Managing aphid populations, which are the primary vectors of TuMV, is crucial. This can be achieved by using insecticides, promoting beneficial insect predators, and using physical barriers like row covers to prevent aphid access.
  • Use reflective mulches. In some cases, using reflective mulches can deter aphids from landing on plants, reducing the risk of virus transmission.