Control efficacy of seven fungicides against Mycogone perniciosa and their safety evaluation to Agaricus bisporus

Toxicity of 7 fungicides against Mycogone perniciosa Magn. and safety evaluation of 5 fungicides to Agaricus bisporus in lab were determined by measuring the growth rate of mycelium.Field trials were conducted to ascertain the control efficacy of 6 fungicides against M. perniciosa and their biological safety to A. bisporus. The results in lab showed that carbendazim,prochloraz,thiabendazole,chlorothalonil,difenoconazole and tebuconazole all exhibited great inhibition to M. perniciosa,with the EC50 value of 0.036 9,0.024 5,0.296,0.136,0.036 0 and 0.058 1 mg/L,respectively.Thiram was comparatively less effective,with the EC50 value of 88.0 mg/L. The results in lab of safety evaluation of several fungicides to A. bisporus showed that carbendazim and chlorothalonil were safe to A. bisporus,while difenoconazole,tebuconazole and thiram had some injury risk to A. bisporus.The field trials revealed that carbendazim(500 g/kg WP),prochloraz-manganese chloride complex(500 g/kg WP) and chlorothalonil(750 g/kg WP) had good control efficacy against M. perniciosa,and was safe to A. bisporus,at the dosage of 250-1 000 mg/kg,200-333 mg/kg and 375 mg/kg,respectively.Tebuconazole(430 g/L SC) decreased the yield of A. bisporus by 20.54% and 13.19%,at the dosage of 143.3 mg/kg and 86.0 mg/kg,respectively.Difenoconazole(100 g/kg WG) decreased the yield of A. bisporus by 4.73%,at the dosage of 33.3 mg/kg.These results demonstrated that tebuconazole and difenoconazole should not be used to control M. perniciosa.Thiram(500 g/kg WP) caused fruiting delay of A. bisporus at 1 000 mg/kg and 500 mg/kg,and showed poor control efficacy at 166.7 mg/kg in the prevention and treatment of mushroom brown rot disease,suggesting it should not be used to control M. perniciosa either.