Objective:The inhibitory activity of single chemical fungicides and their mixed combinations against E.sorghinum was investigated in order to find out the best mixed combination of antifungal effects.Methods:The mixed test of two chemical fungicides was designed by Horsfall method.The inhibition rate of each ratio was determined by mycelial growth rate method,and the toxicity ratio was calculated.Results:Fludioxonil had the highest inhibitory activity against E.sorghinum with EC50 of 0.32 mg/L,followed by prochloraz and flusilazole with EC50 of 0.38,0.52 mg/L,respectively.The inhibitory activities of chlorothalonil,bromothalonil and mancozeb were weak,and the EC50 was 69.24,79.51,84.40 mg/L,respectively.The mixture of flusilazole and captan at a ratio of 6∶4 had the best inhibitory effect,with a toxicity ratio of 1.40,and the mixture at a ratio of 2∶8 had a toxicity ratio of 1.35.Prochloraz and fludioxonil were mixed at a ratio of 3∶7,and the toxicity ratio was 1.34.The toxicity ratio of 5∶5 was 1.31.The highest toxicity ratio of bromothalonil and chlorothalonil in the ratio of 8∶2 was 1.33,followed by 7∶3 toxicity ratio of 1.30.Flusilazole and chlorothalonil were mixed at a ratio of 4∶6,and the toxicity ratio was 1.31.The toxicity ratio of bromothalonil to mancozeb at 7∶3 was 1.28.Conclusion:The mixture of different chemical fungicides could show good synergistic inhibitory activity against E.sorghinum,and most of them were mixed with selective fungicides and protective fungicides,which could better play the role of prevention and treatment.Among them,the mixed combination of flusilazole and captan had the best synergistic effect,followed by the combination of prochloraz and fludioxonil.
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