Screening Of Efficient Fungicides To Control Cobweb Diseases On Flammulina Filiformis And Agaricus Bisporus And The Trials Field

China’s edible fungi industry is developing rapidly,with a total output of 40.4387 million tons in 2020.With the increasing of disease area of edible fungis,the diseases has become the important factor affecting the yield and quality of edible fungi.Cladobotryum varium and Cladobotryum mycophilum were newly discovered diseases in recent years,which have been found in many edible fungus growing areas,and were greatly affected in the yield and quality of Flammulina filiformis and Agaricus bisporus.At present,there is no registration information for the prevention and control of these two diseases in the production of edible fungi.It is urgently to solve in the prevention and control of these two diseases to develop efficient agents for the prevention and control of Flammulina mushroom cobweb disease and bisporus mushroom cobweb disease,improve the prevention and control effect,At the same time delay the development of resistance to chemical pesticides.In this study,prochloraz manganese chloride complex,xinjunanacetate and tetramycin were screened with high activity against C.varium and C.mycophilum by indoor bioassay.The safety of the three fungicides to the growth of F.filiformis and A.bisporus was evaluated,and the control effects were verified by field efficacy test.Meanwhile,the residues of prochloraz manganese chloride complex and xinjunanacetate in the fruiterbodies of F.bisporus were detected.The main results are as follows:1.The toxicity of 9 fungicides to C.mycophilum was measured by mycelium growth rate method.Among them,tetramycin,prochloraz manganese chloride complex and xinjunanacetate had higher toxicity to the mycelial growth of C.mycophilum.EC₅₀values were 0.269,0.939,0.990 mg/L,respectively.The toxicity of 8 fungicides against spore germination was determined by spore germination method.The two fungicides,xinjunanacetate and tetramycin,showed high toxicity against spore germination to C.mycophilum,with EC₅₀values of 0.652 and 1.365 mg/L,respectively.The toxicity of 10 fungicides against C.varium was measured by mycelial growth rate method.The xinjunanacetate,prochloraz manganese chloride complex and tetramycin had higher toxicity to the mycelial growth of F.filiformis.EC₅₀values were 0.039,0.331 and0.303 mg/L,respectively.The toxicity of 7 fungicides against spore germination was determined by spore germination method.Two fungicides,xinjunanacetate and tetramycin,showed high toxicity to spore germination to C.varium,with EC₅₀values of 1.896 and 2.564mg/L,respectively.2.The mycelial growth safety tests fungicides to F.filiformis and A.bisporus were tested,and three fungicides,prochloraz manganese chloride complex,xinjunanacetate and tetramycin were safe for mycelial growth at the application dose.The safety tests of fungicides on fruiting body in mushroom shed showed that 0.3%tetramycin aqueous solution,1.8%xinjunanacetate aqueous solution and 50%prochloraz manganese chloride complex wettable powder had no adverse effect on fruiterbodies growth of A.bisporus and F.filiformis.3.The results of two years field efficacy test showed that the average control effects was76.96%,and the doses of 0.3%tetramycin aqueous solution was 1.00 mg/L.When the doses of 1.8%xinjunanacetate aqueous solution was 6 mg/L,the average control effects was79.83%.The average control effects of 50%prochloraz manganese chloride complex salt wettable powder was 57.08%,with the doses of active ingredient was 400 mg/L.The average control effects was 81.17%,with the doses of 1.8%xinjunanacetate aqueous solution was 6 mg/L.When the doses of 0.3%tetramycin aqueous solution was 1.00 mg/L.The average control effect of 0.3%tetramycin aqueous solution was 75.29%.The average control effect of 50%prochloraz manganese chloride complex wettable powder aqueous solution was 400 mg/L was 61.38%.The three fungicides had good control effects on Cobweb Diseases of F.filiformis and Cobweb Diseases of A.bisporus.4.The final residues of 1.8%xinjunanacetate aqueous solution and 50%prochloraz manganese chloride complex wettable powder 6 and 400 mg/L at 250 m L/m~2for 9 days were 0.116 and 1.325 mg/kg,respectively,which were lower than the maximum residue limit standard and could be used in Agaricus bisporus.5.Combined with the above results,0.3%tetramycin aqueous solution,1.8%xinjunanacetate aqueous solution and 50%prochloraz manganese chloride complex wettable powder were safe to the growth of F.filiformis and A.bisporus,and had good control effects on Cobweb Diseases on F.filiformis and Cobweb Diseases on A.bisporus in the fields.The recommended doses of the active ingredient dosage in the fields were 0.3%tetramycin aqueous solution 0.7to 1.0 mg/L,1.8%xinjunanacetate aqueous solution 2 to 6 mg/L,and 50%prochloraz manganese chloride complex wettable powder 400 mg/L,respectively.