Abstract:The antagonistic activity of Bacillus amyloliquefaciens strain SJ06 against Bipolaris maydis was tested by confrontation culture, and the antifungal activity of fermentation supernatant, crude lipopeptide extracts and pyraclostrobin were determined by mycelial growth rate. The synergic antifungal activity of crude lipopeptide extracts of strain SJ06 and pyraclostrobin was obtained by mixing them in different proportion. The results showed that the inhibition rate of strain SJ06 against Bipolaris maydis was 71.43%. The EC50 of fermentation supernatant and crude lipopeptide extracts to Bipolaris maydis was 0.88 μL/mLand 0.23 μL/ mL, respectively. The EC50 value of pyraclostrobin to Bipolaris maydis was 1.10 μg/mL. The toxicity ratio of the combination of crude lipopeptide extracts and pyraclostrobin to Bipolaris maydis was more than 1, which indicated that the inhibition effect of the combination was synergism. Among them, the proportion of 4:6 had the strongest synergistic effect, and the toxicity ratio was 1.21.