The principa This study conducted the tests in vitro with Bacillus subtilis, Pseudomonas sp. RC, Azospirillum brasilense and Rhizobium meliloti against Bipolaris spicifera, Curvularialunata, Fusarium spp., Nigrospora oryzae, Exserohilum rostratum, Alternari aspp. And Thanatephoruscucumeris via the dual culture technique, and found that each bacterium was varied in its inhibitory effect on each pathogen. The interaction between pathogens conidia, sclerotia germinated and B.subtilis, Pseudomonas sp. RC, A.brasilense and R.meliloti showed abnormal hyphal swelling, lyses and completed degradation of the hyphal tip. The results have been seen that the controls where no cultures were incubated in the wells, the fungal culture continued to grow and covered the 9 cm petri dishes in 7 days. Clear inhibition zones were observed in the interaction area between N.oryzae R9+B.subtilis, B.spicifera R15+B.subtilis, A.alternata R18+B.subtilis, N.oryzae R9+Pseudomonas sp. RC, T.cucumeris R12+Pseudomonas sp. RC, A.alternata R18+Pseudomonas sp. RCand A.alternata R20+ Pseudomonas sp. RC. And found that there were a great inhibition zones that were observed between pathogens by approximately 83.33% respectively around the fungal culture. R.meliloti revealed moderate inhibition activity towards T.cucumeris R2, and gave value roughly 77.77%. However, A.brasilense was determined as the bacteria with the weakest inhibitory activity against N.oryzae R9; it recorded the lowest level of inhibition which was scored 66.66%.
