Ralstonia solanacearum

Bacterial wilt, brown rot


Ralstonia solanacearum is a plant pathogenic bacterium. It is a soil-borne disease and colonises the xylem, causing bacterial wilt and brown rot in a very wide range of potential host plants.

Life cycle and appearance of Bacterial wilt, brown rot

Ralstonia solanacearum is a quarantine organism in Europe and considered a bioterrorist organism in the United States. It is a commonly found soil-inhabitant in tropical and subtropical regions and is transferred by the introduction of propagation materials (seed potatoes, cuttings of ornamentals) from warmer regions. Different races are distinguished with a differing, but overlapping host-range. Race 3 is pretty much restricted to potato and tomato. Whereas other races have optimum temperatures of 35-37 °C, the optimum for Race 3 is 27 °C, which makes it more dangerous in temperate regions. It survives well in water and in many different soil types and on alternative hosts like weeds. It invades the plants through wounds or stomata and then spreads into the xylem vessels. In potato, it is tuber-borne. Spread from plant to plant results from bacteria moving from the roots of infected plants to neighbouring plants. The bacteria can also be transported by irrigation water.

Disease incidence is highest when soil moisture is high, such as during rainy periods. When temperature is low, infection may remain latent until conditions are more favourable. This makes it more difficult to recognize infected fields.

How to prevent Bacterial wilt, brown rot

  • Use disease free propagation materials (seed, cuttings, tubers)
  • Disinfect cutting knives and tools
  • Control root rot nematodes as the wounds they make on roots help the bacteria to infect the crop
  • Do not use cut potatoes for propagation, since cutting tubers can increase disease incidence with up to 250%
  • Quarantine measures are in place, including a five-year ban on using a field for potato cropping after infection of potatoes from that field has been established

Prevent plant diseases by optimizing plant potential and crop resilience.