Biological control of bacterial wilt of tomato caused by Ralstonia solanacearum using Pseudomonas species isolated from the rhizosphere of tomato plants

Tomato bacterial wilt, caused by Ralstonia solanacearum, is one of the devastating soil-borne diseases of tomato plants in Nigeria. We investigated the potentiality of indigenous Pseudomonas species in controlling bacterial wilt of tomato. Seven Pseudomonas species were isolated and identified from the rhizosphere of tomato plants. The isolates were screened for enzyme production, and in vitro antimicrobial activity against pathogenic R. solanacearum using dual plate culture method. The biocontrol and growth-promoting efficacy of the Pseudomonas species were studied in the screenhouse using a completely randomised design. P. aeruginosa, P. syringae and P. fluorescens produced lipase, protease and alpha-amylase enzymes. All the Pseudomonas isolates except P. aureofaciens inhibited the growth of R. solanacearum. Since the tested species reduced the incidence of bacterial wilt and promoted the growth of the tested tomato genotypes, the indigenous Pseudomonas strain could be used to develop active biocontrol agents of tomato bacterial wilt in Nigeria.