The effect of addition of Cu and Mn on antagonistic ability of Bacillus siamensis ST4 and Bacillus amyloliquefaciens LB2 as plant pathogenic bacteria antagonist agents

Bacillus sp. plays an important role as a biological control agent especially plant pathogens. The bacteria used in this study were Bacillus siamensis ST4 and Bacillus amyloliquefaciens LB2. Competition mechanism and antibiosis Bacillus plays an important role as a biological control agent. This mechanism can work effectively with adequate nutrition. The addition of Cuprum and Mangan can affect the growth increase and antagonistic ability of B. siamensis ST4 and B. amyloliquefaciens LB. This study was conducted to determine the growth and antagonistic ability of B. siamensis ST4 and B. amyloliquefaciens LB2 against Xanthomonas axonopodis pv glycines and Xanthomonas oryzae pv oryzae. The method used was a Completely Randomized Design (CRD) with 5 treatments including control, Cu 20 ppm, Cu 25 ppm, Mn 40 ppm and Mn 45 ppm, each of which was repeated 5 times. The variables observed were bacterial viability and antagonism against X. axonopodis pv glycine and X. oryzae pv oryzae. The results showed that the addition of Cu and Mn to the growth medium of B. siamensis ST4 and B. amyloliquefaciens LB2 affected the stationary phase pattern of bacteria, and reached the highest peak exponential phase at 3 days after inoculation. The addition of Cu and Mn to all concentrations of B. siamensis ST4 increased the inhibition of X. oryzae pv oryzae, while B. amyloliquefaciens LB2 increased the inhibition of X. axonopodis pv glycines.