Efficacy and persistence of micobial antagonists against Sclerotium Rolfsii under field conditions

Sclerotium rolfsii showed significant negative effect on plant growth due to severe root colonization,whereas,presence of the microbial antagonists showed significant positive effect on plant growth by reducing the colonization of roots by s. rolfsii. highest root colonization by s. rolfsii and significant reduction in plant growth were observed in sunflower and mungbean plants growing in soil artificially infested with sclerotia of s. rolfsii. use of biocontrol agents in s. rolfsii infested soil showed significant reduction in root colonization index accompanied by increase in plant growth. bradyrhizobium sp.,was found most effective (p<0.01) followed by rhizobium sp.,trichoderma harzianum,t. pseudokoningii,t. polysporum and t. virens. efficacy of biocontrol agents was comparatively suppressed in s. rolfsii infested soil as compared to non-infested soil. there was no significant difference in plant length in infested and non-infested soils where biocontrol agents were used. however,plant weight was less in infested soils as compared to non-infested soils. the microbial antagonists persisted in the soil and produced similar results when mungbean and sunflowers were re-sown in the same plots.