Bacterial Soft Rot

Bacterial soft rot is a common disease caused by a soil dwelling bacteria. It does not appear to survive in the soil but can survive on plant debris.I

Infection enters through wounds as those caused by slugs or carrot root fly.

Susceptible Plants- Bacterial soft rot effect primarily the Brassicas, Rutabagas, turnips, celery, cucurbits, leeks, lettuce, onion, parsnip, potato, tomato, and cyclamen.

Damage - infected plant tissues first develop a water-soaked lesion that enlarges rapidly in diameter and depth. The affected area becomes soft and mushy and generally turns a dark color in advanced stages of disease development.

Soft rot-infected cruciferous plants almost always give off an offensive odor, perhaps in part due to invasion by secondary organisms. Disease losses from soft rot may occur in the field, transit, or storage.

Symptoms - Soft rot bacteria persist in infected plant debris, in association with plant roots, in low numbers in the soil, and in association with several insects. Wounds such as leaf scars, insect injury, mechanical injury, lesions caused by other pathogens, etc. are the primary avenues of soft rot bacterial invasion.

Rainfall and high temperatures enhance infection in the field. Transit and storage infection may develop from bacterial contamination that occurred in the field or during postharvest from handling equipment and storage containers. Soft rot bacteria can grow over a temperature range of 41-98 F (5-37°C) with an optimum temperature of about 72 F(22°C.)

Prevention and Control- Disease management is based primarily on sanitation and cultural practices. Sufficient time should be allowed for crop residues to decompose before planting a second crop. Vegetable crops should be rotated with cereals or other non-susceptible crops. Fields should be well drained to reduce soil surface moisture and plants should be spaced sufficiently to allow ventilation for rapid drying of foliage.

Rain shelters to prevent soil splash and foliage wetting should also reduce soft rot incidence. When growing vegetables use a strict crop rotation- minimum 3 years, 4-5 years is preferable. Once the soft bacteria has started there is no cure. Simply remove and dispose the plants infected with bacterial soft rot..