In vitro Efficacy of Casing and Compost Isolated Bacterial Inoculants against Verticillium fungicola (Preuss) Hassebrauk and Agaricus bisporus (Lange) Imbach

摘要

The aim of this study is to determine some effective antagonistic bacterial inoculants for the biological control of Verticillium fungicola causing dry bubble disease of white button mushroom (Agaricus bisporus). Out of the 32 bacterial inoculants isolated from the casing and compost materials and screened against V. fungicola, only 5 isolates were selected for further investigation. The cell free culture filtrates of these bacterial isolates were further evaluated against the pathogen and host fungus at different concentrations. The bacterial culture filtrates inhibited mycelial growth and conidial germination of V. fungicola to varied extents. The isolate PC-I showed maximum inhibition 71.50 per cent of mycelial growth and similar trends of inhibition were recorded in case of conidial germination (84.13 per cent of the pathogen) followed by PS-I, PS-II, Bacillus thuringiensis, BC-IX, BC-V and BC-IV, respectively. Azotobacter sp. proved less effective in inhibiting the mycelial growth of the pathogen. The culture filtrates of PS-I and PS-II stimulated the growth of A. bisporus at all the test concentrations, whereas the remaining culture filtrates inhibited its growth.