Sustainable management strategies for bacterial wilt of sweet peppers (Capsicum annuum) and other Solanaceous crops.

Pepper bacterial wilt is caused by the bacterial pathogen, Ralstonia solanacearum. It is the most destructive disease of many Solanaceous crops such as potatoes, tobacco, pepper, tomatoes and eggplant and is a significant source of crop loss worldwide. Physical, cultural and chemical controls have been employed to combat this destructive disease. However, none of these strategies has been able to control the disease completely due to the broad host range and genetic diversity of the pathogen, its prolonged survival in the soil and survival on vegetation as a latent infection. Owing to co-management strategies, biological control is the best approach for human health and environmental friendly motivations. It makes use of various antagonistic rhizobacteria and epiphytic species such as Bacillus cereus, Pseudomonas putida, Bacillus subtilis, Paenibacillus macerans, Serratia marcescens, Bacillus pumilus and Pseudomonas fluorescens, which compete with and ultimately inhibit the growth of the pathogen. The possible mechanisms of biocontrol by these species involve multifaceted interactions between the host, pathogen and the antagonists. These can involve competition for nutrients and space, plant-mediated systemic resistance, siderophore production and production of extracellular cell wall degrading enzymes to inhibit or suppress the growth of the bacterial wilt agent.