Field performance assessment of formulated Pseudomonas fluorescens for enhancing plant growth and inducing resistance against rice blast disease

Abstract

To control blast disease in the rice field under natural conditions, three antagonistic isolates of rhizospheric P. fluorescens were formulated in talc, kaolinite, PVP, and vegetable oil using an RCBD with three replications. At various phases of the rice plants' growth, all of the products markedly accelerated plant growth and yield-contributing characteristics. Pf-8, compounded in talc (5 %) and vegetable oil (2 %) among the three isolates of P. fluorescens, significantly elevated vegetative and yield parameters with higher (2.11 and 2.08) benefit-cost ratios, respectively. At 90 days after transplanting (DAT), T11 (5 % Pf-8 Talc) and T13 (2 % Pf-8 Vegetable oil) showed a significant reduction in blast incidence (76.81 %, 75.45 %) and severity (71.57 %, 69.82 %), with the largest populations of P. fluorescens (9.60 × 1010 and 9.51 × 1010) in the rhizosphere. Moreover, a significantly increased level of phenol and hydrogen peroxide (H2O2) was found in Pseudomonas-treated leaves (Pf-8) at 30, 60, and 90 DAT indicating a strong relationship with rice blast disease reduction. Further, blast incidence and severity showed a negative correlation with vegetative parameters, yield parameters, phenol, and H2O2. Thus, it may be claimed that using formulated P. fluorescens (Pf-8) to manage rice blast in the field could be an alternate strategy to using chemicals.