PREPARATION OF NEW BIOFUNGICIDES USING ANTAGONISTIC BACTERIA AND MINERAL COMPOUNDS FOR CONTROLLING COTTON SEEDLING DAMPING-OFF DISEASE

摘要

The overuse of chemical pesticides in agriculture has caused serious environmental problems and thus the demand for safer pesticides is increasing. One alternative is microbial pesticides that suppress plant pathogens via their microbial activities. As microbial pesticides are eco-friendly products, in this study we prepared four biological fungicides using two isolates of Pseudomonas fluorescens that included a talc-based powder and bentonite-based powder as mineral carriers. Then we evaluated the efficacy of these products in controlling cotton seedlings, damping-off, a fungal disease caused by Rhizoctonia solani at four intervals of 15, 30, 45 and 60 days after sowing the cotton seeds under greenhouse conditions. The results of greenhouse experiment on application of biofungicides showed that the efficacy of Bentonite-B-1 treatment to control R. solani was promising as it increased the number of healthy seedlings 3.42 to 3.57 - fold and was much more effective than the carboxin/thiram fungicide in all stages.