Evaluation of Combined Efficacy of Pseudomonas fluorescens and Bacillus subtilis in Managing Tomato Wilt Caused by Fusarium oxysporum f. sp. lycopersici (Fol)

摘要

The objective of this study was to evaluate the individual and combined efficacy of Pseudomonas fluorescens (EPI-5, KPI-7, ANR-2 and RTM-3) and Bacillus subtilis (KGI-4, PYR-3 and OCM-6) strains to promote the growth and yield parameters of tomato andto manage Fusarium wilt disease under in vitro and greenhouse conditions. The dominant pathogen which causes Fusarium wilt of tomato, was isolated and identified as Fusarium oxysporum f. sp. lycopersici (FOL). Twenty five native bacterial antagonists were isolated from healthy tomato rhizosphere soil in different geographical regions. Under in vitro conditions, the results revealed that the combined application of EPI (Pf-5)+KGI(Bs-4)+KPI (Pf-7) was found to effectively inhibit the mycelial growth of the pathogen (by 40%) when compared to application of individual strains of the bacterial antagonists. The above strains of P. fluorescens and B. subtilis were found compatible. Under greenhouse conditions, the combined application of EPI (Pf-5)+KGI (Bs-4)+KPI (Pf-7) exhibited the highest disease reduction. Also, tomato plants treated with EPI (Pf-5)+KGI (Bs-4)+KPI (Pf-7) strains showed a significant stimulatory effect on plant height and increased the dry weight of tomato plants up to 27% in comparisonto the non-bacterized control. The combined strains also increased tomato fruit weight. It could be concluded that synergistic consortia of beneficial bacteria isolated from rhizosphere soil are perfectly able to promote plant growth and could be exploited for sustainable management of soil borne diseases especially, Fusarium wilt of tomato.