CONTROL OF CHARCOAL DISEASE ON BROADBEAN USING AZOSPIRILLUM BRASILENSE AND BOKASHI

Abstract

This study was conducted to evaluate the efficiency of the bacteria Azospirillum brasilense and bokashi against Macrophomina phaseolina, the causal agent of charcoal rot on broadbean, on cultural medium and under greenhouse conditions. The results showed that the addition of A. brasilense into potato dextrose agar (PDA) at 3x106 CFU/ml caused an inhibition of 63.3% in fungal radial growth compared with zero inhibition in control (without bacteria). The biological activity of A. brasilense was 69.2% against the fungus on PDA after 7 days of incubation at 25 + 2 oC. The bacterial filtrate of A. brasilense induced a significant reduction in fungal dry biomass which attained 61.8 mg compared with 125.8 mg in control. The addition of A.brasilense suspension containing 6x106 CFU/ml at 100 ml / pot found to be the more efficient than the other treatment in reducing the infection percentage (33.3%) compared with 100% in control under greenhouse conditions, while the addition of bokashi into the soil gave the lower disease severity (18.3%) compared with 68.3% in control. The amendment of potting soil with bokashi was found to be more efficient in increasing the fresh and dry weights, chlorophyll a, b, total chlorophyll and carotenoids in broadbean plants which were 140, 41.33 gm, 25.66, 27.61, 53.27 and 21.39 mg/ml compared with 110, 16.67 gm, 21.71, 25.02, 46.73 and 17.62 mg/ml in control respectively.