Effect of seed coating material in the efficacy of microbial antagonists for the control of root rot fungi on okra and sunflower

The biological potential of different microbial antagonists viz., Bacillus thuringiensis, Rhizobium meliloti, Aspergillus niger and Trichoderma harzianum was examined by coating the seeds with gum arabic, glucose, sugar and mollases in the suppression of root rot fungi viz., Macrophomina phaseolina, Rhizoctonia solani and Fusarium spp., on okra and sunflower plants. All biocontrol agents enhanced the germination and growth of plant as compared to control. Shoot length, shoot weight, root length, root weight were significantly increased in both okra and sunflower. Maximum plant height was observed where seeds of okra and sunflower were coated with T. harzianum using 2% of glucose followed by gum arabic, mollases and sugar solution. Gum arabic was found more effective in reducing infection by root rot fungi viz., M. phaseolina, R. solani and Fusarium spp. Of the different microbial antagonists used, T. harzianum was found more effective followed by B. thuringiensis, R. meliloti and A. niger in the control of root rot fungi.