Compatibility of biocontrol agents and N fixing organisms with post emergence pre-mix herbicide-bispyribac sodium + metamifop 14 % SE

Abstract

he experiments were conducted in vitro in the Agricultural Microbiology laboratory at College of Agricul-ture, Vellayani, Thiruvananthapuram, Kerala, India to evaluate the compatibility of biocontrol agents Pseudomonas fluorescens and Tricoderma viride and N fixing organisms Azospirillum lipoferum and Azotobacter chroococcum to bispyribac sodium + metamifop 14 % SE, a new broad spectrum post emergence pre-mix herbicide mixture used for weed control in rice. The experiments were conducted in completely randomized block design with seven different concentrations of herbicide viz., 100, 120, 140, 160, 180, 200 and 220 ?L L-1 corresponding to field doses of 50, 60, 70, 80 90, 100 and 110 g ha-1 and a control (0 ?L L-1). All the tested concentrations of the herbicide mixture were highly compatible with P. fluorescens, A. lipoferum and A. chroococcum. The radial colony diameter of T. viride was significantly influenced by different concentrations of the herbicide. The field dose of bisspyribac sodium + met-amifop up to 90 g ha-1 (180 ?L L-1) is harmless to T. viride, since it recorded a growth inhibition of only 22.96 per cent but higher doses (100 and 110 g ha-1) which recorded a growth inhibition of 31.48 and 37.04 per cent respectively were slightly harmful to the antagonistic fungus. The compatibility results revealed the possibility of using bispyribac sodium + metamifop for weed control at recommended doses (70, 80 or 90 g ha-1) under bio intensive disease management programme involving P. fluorescens / T. viride and nutrient management programme involving A. liopferum / A chroococcum.