Pectobacterium carotovorum subsp. carotovorum

(Jones 1901) Hauben et al. (1999)

bacterial rot

General  

• Bacterium widespread worldwide, especially in production areas with humid and rather hot climatic conditions: tropical and equatorial areas par excellence.
• Responsible for damp and foul-smelling rots on various organs of vegetables.
• Extremely polyphagous bacterium that can affect many vegetables.
• Observed in the open field as well as under shelter.

• Susceptible botanical family(s) :

Biology

• Conservation : persists for several years in many soils, especially in plant debris and in the aqueous phase, for example in washing or water storage tanks. Also maintained on a fairly large number of cultivated and non-cultivated hosts, especially herbaceous broadleaf weeds. It affects many vegetables (Solanaceae, salads, celeriac, cabbage, basil, fennel, etc.).
• Infection : penetrates the various organs mainly through wounds (peduncular scar, mechanical injuries, insect-related damage, effects of sand, etc.), following various cultural operations during cultivation or after harvest (harvesting in wet periods , fruit washing). May also invade tissues secondarily after other pathogens.
• Development - Dissemination : multiplies in large quantities in infected tissues; easily disseminated by water in splashes and runoff. Insects, as well as tools during cultural interventions, contribute to its dispersal.
• Favorable conditions :
  • Mainly favored by humid and warm conditions. Cloudy and rainy periods increase the risk of seeing this bacteria proliferate. It seems capable of developing at temperatures between 5 and 37°C, its optimum being between 25 and 30°C.
  • Poor control of the storage temperature of certain vegetables, the presence of wounds, the use of dirty water during washing favor the expression of its parasitism.
  • Very vigorous plants seem more susceptible.

Protection  

• Implement crop rotations , a measure that is not easy to manage given its very many potential hosts.
• Think about integrating plants that are not very sensitive, even resistant (soybeans, grasses, rice, etc.) into the rotation.
• Plant preferably in plots located in well ventilated places.
• Promote  soil drainage and avoid excess humidity; monitor the sanitary quality of the water.
• Ensure a balanced manure, avoid excess nitrogen , and destroy weeds .
• Avoid injury and water stress.
• Quickly eliminate diseased plants .
• Lower the hygrometry of the vegetation and avoid as much as possible the ground being too wet, ventilate the shelters.
• Avoid overhead irrigation ; if it is not possible to proceed otherwise, such irrigations will be carried out rather in the morning than in the evening, so that the plants dry quickly during the day.
• Do not work in the plots when the plants are wet: the risk of transmission of bacteria by contact is then high.
• Harvest vegetables or fruits in dry weather and taking care to limit injuries as much as possible. Refrigerate them quickly or store them in a cool, dry place.
• Eliminate and destroy the affected plants at the end of cultivation, and in particular the root systems and stems, avoid burying them in the ground.