Determinations of in vitro Antagonistic Effects of Microbiomes Isolated from Vermicompost Against Major Plant Fungal Disease Agents of Vegetables

In this study, in vitro antagonistic potentials of bacterial microbiomes, obtained from earthworm fertiliser, vermicompost, were investigated on inhibitions of mycelial growth of major foliar and soilborne fungal disease agents Sclerotinia sclerotiorum, Macrophomina phaseolina, Botrytis cinerea, Verticilium dahliae. Total of 69 putative bacterial biocontrol agent (BCA) isolates were obtained from commercial vermicompost lots. Among them, 28 bacterial isolates (49.12% of total isolates) were inhibited mycelial growth of S. sclerotiorum by 1.72-75.43%, M. phaseolina by 1.67-65.83%, B. cinerea by 3.44-57.18%, V dahliae by 2.28-58.74%, respectively. Majorities of bacterial isolates were identified as Bacillus spp. Certain isolates of Bacillus spp. have caused noticeable morphological changes on mycelia of S. sclerotiorum. Antagonistic potentials of bacterial isolates were found to increase by pre-incubation time prior the fungal inoculation. Due to high antagonistic properties, efficient isolates of Bacillus spp. may be used as biocontrol agent against soilborne diseases as an alternative to pesticides to promote organic and sustainable agriculture.