Biological control of bacterial wilt of solanaceous vegetable crops - a review

Bacterial wilt of solanaceous crops is caused by Ralstonia solanacearum (Smith) Yabuuchi et al. which includes a “species complex” that provides it high heterogeneity. The wilt disease reduces the production of crops significantly. The bacterium R. solanacearum is gram-negative, small rod with rounded ends, non-fluorescent, non-endospore forming, strict aerobe and has polar flagella (when present). All phylotypes i.e. I, IIA, IIB, III & IV, race 1 & 3 and biovars 1, 2 2T, 3 & 4 infect solanaceous crops to cause wilt disease. The pathogen has variability during its survival in the soil for a longer period which restricts the control of wilt disease. Besides, there are no such chemicals available to control wilt disease effectively at field level. An alternative approach is biological control which is ecofriendly and very effective in integrating with other management practices for controlling the disease. Biological control includes microbes, organic matter, botanicals, animal wastes and resistant varieties which are used either alone or combined with other methods to improve disease management. The microbes particularly fungi and bacteria have advantage over chemical control such as self-sustaining, self-spreading, reduced input by renewal capacity, long-term disease suppression and eco-friendly.