Management of bacterial wilt of chilli caused by Ralstonia solanacearum(E.F Smith) yabuuchi et al. using AMF and flurescent pseudomonads

Abstract

Management of bacterial wilt of chilli caused by Ralstonia solanacearum (E.F. Smith) Yabuuchi et al. using AMF and Pseudomonas fluorescens was studied. The pathogen was isolated and pathogenicity proved. Based on the cultural, morphological, physiological and biochemical characteristics, the isolate was identified as R. solanacearum. Out of the ten native AMF cultures screened, cultures M5 and M7 were found effective for disease suppression and growth improvement in chilli.Pseudomonas spp. were isolated from phyllosphere and rhizosphere of chilli plants collected from different locations of Thiruvananthapuram district. Out of the 45 isolates subjected to in vitro screening by dual culture technique, two best isolates viz., Pf-14 and P-1 were selected. These isolates, Pf-14 and P-1 were subjected to biochemical characterization and were tentatively identified as Pseudomonas aeruginosa and Pseudomonas fluorescens biovar 2 respectively.Interaction of efficient native isolates of AMF and P. fluorescens isolates on disease suppression and growth improvement in chilli was studied. Talc based formulation of the two best native isolates, Pf-14 and P-1 were applied as soil drench and foliar spray. Dual inoculation of chilli seedlings with M5 and P-1 recorded the least disease incidence. The growth, biomass production and yield was highest for the treatment M7P1R0 which is a combination of AMF culture M7 and Pseudomonas culture Pf-14. The application of antibiotic agrimycin was found ineffective in suppressing bacterial wilt pathogen.The present study forms the first report of the synergistic interaction of AMF and P. fluorescens for the management of bacterial wilt and growth improvement in chilli. The technology of combined inoculation of AMF and P. fluorescens could be recommended for adoption by the vegetable farmers of Kerala after confirming the results under field conditions.