Effect of Pseudomonas fluorescens on Fusarium Wilt Pathogen in Banana Rhizosphere

Abstract

A detailed study was conducted to find out the efficacy of Pseudomonas fluorescens on fusarium wilt pathogen in banana rhizosphere. All the strains of P. fluorescens isolated from banana rhizosphere had significant inhibitory action on the growth of Fusarium oxysporum f.sp. cubense. Among the strains, Pfm of P. fluorescens had higher inhibitory action while comparing with other strain. Talc formulation of Pfm of P. fluorescens was prepared and applied in three month old banana plants to study their efficacy on fusarium wilt disease. After three month of inoculation, Pfm of P. fluorescens inoculated at 10 and 15 g plant ha-1 showed lesser vascular discoloration index than the control. To study the rhizosphere colonizing ability in banana rhizosphere against fusarium wilt disease, a rifampicin resistant strain of Pfm of P. fluorescens was developed. The banana plants inoculated with a rifampicin resistant strain of Pfm of P. fluorescens showed gradual increase in population of P. fluorescens in the rhizosphere over the period of time upto 60 days after inoculation. The extracts of soil inoculated with rifampicin resistant strain of Pfm of P. fluorescens at 10 g plant ha-1 showed significant reduction in spore germination of F. oxysporum f.sp. cubense. Gradual increasing in the reduction of spore germination was observed in the soil extracts over the period of inoculation upto 60 days after inoculation. Similarly, the filter paper dipped in extracts of soil had higher inhibition of growth of F. oxysporum f.sp. cubense at 60 days after inoculation.