Eco-Friendly Management of Soil Borne Diseases in Brinjal Through Application of Antagonistic Microbial Population

Abstract

In Assam, bacterial wilt, a soil borne disease caused by Ralstonia solanacearum Yabuchi et al. is the major constraint for production of solanaceous vegetables. Present study was made to evaluate the efficacy of substrate based bioformulation of a PGPR, Pseudomonas fluorescens against the bacterial pathogen in brinjal (Solananum melengona) under field condition. Inhibitory activity of P. fluorescens was tested against R. solanacearum following dual culture method. Three substrates, viz., vermicompost (VC), mustard oil cake (MOC) and farm yard manure (FYM) were compared for mass multiplication of the antagonist. The highest population was recorded (105.56 x 108 cfu/g) when mass cultured in VC along with a standard sticker CMC and an osmoticant mannitol. Quantitative assay of population of P. fluorescens revealed that it could maintain high population count up to 180 days of storage at room temperature. Different method of application of the substrate based bioformulations viz., seed treatment (ST), root application (RA), soil application at transplanting (SA) and soil application at 30 days after transplanting (30 DAP) and combined application of all the methods showed minimum wilt incidence and maximum disease reduction in brinjal. Minimum wilt incidence (0.25%) was recorded in the treatment comprising combination of ST, RA, SA and 30 DAP with maximum disease reduction. Following the trend of reduction in disease incidence, yield was maximum (34.40 t/ha) in this treatment and also showed the highest recovery of P. fluorescens strain-Pf-D1 in the soil rhizosphere after harvest (77.40 x 108 cfu/g). Vermicompost appeared to be the best nutrient source to support the antagonist for maximum multiplication and disease reduction and combined application of ST, RA, SA, 30 DAP was most effective bacterial wilt disease management in brinjal.