Screening of Fungicides Against Tobacco Sore Shin in Laboratory

The inhibition effects of 4 fungicides,difenoconazole,myclobutanil,prochloraz-manganese chloride complex and triadimefon,against Rhizoctonia solani Kühn were determined by mycelium growth rate test,and more effective fungicide mixtures were screened.The results indicated that both 10% difenoconazole EC and 12.5% myclobutanil EC had good inhibition effects to Rhizoctonia solani Kühn,their EC₅₀ were 0.56 and 0.8 μg/mL,respectively.The 12% compounded agent EC,which was prepared by the mixture of 12.5% myclobutanil EC and 10% Difenoconazole EC at a ratio of effective concentration 4:1,had better inhibition effects to Rhizoctonia solani Kühn with EC₅₀ and CTC of 1.02 μg/mL and 155.3 respectively,and showed significant synergism.The 12% compounded agent EC at a dilution of 1500 had the best control effect,its relative control effect reached 96%.