Southern bacterial wilt is causing diseases n Louisiana vegetables

Summer is the perfect time for gardening, but the fruits of your labor may be lost due todiseases on the rise in Louisiana vegetables.

LSU AgCenter studies show vegetable growers all over Louisiana are facing southern bacterial wilt and a bacterial spot in tomatoes and pepper production. Southern bacterial wilt (or bacterial wilt) is a destructive disease of tomatoes and plants of the nightshade family which is known as solanaceous.

In addition to vegetables of the nightshade family, the bacterium can cause disease in ornamentals. Infected plants rapidly wilt due to loss of turgidity of leaves and stems, giving the plants a limp appearance. "Initially, these plants may recover overnight but as the disease develops, rapid drying of the foliage occurs, leading to permanent wilting and death of the plant," said Plant doctor Raj Singh.

Disease prevention through soil fumigation may reduce the incidence of disease early in the season, but it has not provided long-term control. Alternatively, oil solarization of contaminated fields during summer may also help in reducing the initial population of bacterium in the soil according to LSU Agcenter.

"Initially, these plants may recover overnight," Singh said. "But as the disease develops, rapid drying of the foliage occurs, leading to permanent wilting and death of the plant."

Symptomatic plants will exhibit discoloration of the vascular system. Brown, sunken cankers are also often visible at the base of the plant near the soil line. According to Singh, The bacterial wilt is caused by the soil-borne bacterium called Ralstonia solanacearum and is spread within fields by the movement of infested soil, in surface water, and the handling of infected plants.

Bacterial leaf spot of bell and hot peppers caused by Xanthomonas species is another pathogen known to infect all above-ground plant parts including fruits, leaves and stems. The pathogen is seed-borne, and the development is favored by warm and rainy weather.

Symptoms start with small tan/brown spots, which become large dark brown in four to five days. Leaf spots are irregular in shape with water-soaked margins and appear greasy. Infected plants defoliate prematurely and rapidly. There are no commercially available resistant/tolerant varieties that are recommended but the LSU AGcenter suggests commercial and home growers follow good sanitation practices to reduce the spread of the disease.

Avoiding movement of infested soils, avoiding movement of stakes from known infested sites to other sites and proper cleaning of tools can help.