Blackleg of Potatoes
HOSTS
- Potato
DESCRIPTION
Blackleg in potatoes is caused by bacteria species in the genera Pectobacterium and Dickeya. These pathogens can cause other diseases, such as bacterial soft rot and aerial stem rot. Blackleg usually refers to infections caused by contaminated seed potatoes, however, the bacteria can also be spread on soil, tools, and water.
BIOLOGY
Blackleg bacteria is primarily introduced to fields through infected seed potatoes. Some potatoes may be asymptomatic, but still harbor the bacteria. When an infected tuber is planted, the bacteria will reproduce and spread through the vascular system to infect the developing tubers and the soil around the plant. The bacteria can move through moisture in the soil to find other hosts.
Blackleg can continue to be spread when potatoes are harvested or in storage.
SYMPTOMS
- Stunted or reduced growth
- Dark, water-soaked lesion at the base of the stem
- Slimy stem and tuber decay in wet conditions
- Black rotted pith in dry conditions
- Chlorotic foliage that may wilt and collapse
GENERAL MANAGEMENT
- Use certified disease-free seeds
- Sanitize tools and equipment
- Rotate with non-susceptible crops
- Avoid watering practices, such as overhead irrigation, that result in wet soil and plants for prolonged periods
- Remove infected plants and plant debris
- Properly cure and store crops after harvest