Toxicity Comparison of Nine Fungicides to Glomerella cingulata

The susceptibility of Glomerella cingulata isolated from apple to 9 fungicides were tested using the mycelium growth rate method.The results showed that the susceptibility of triazole fungicides declined following the order of tebuconazole,hexaconazole,flusilazole,difenoconazole,myclobutanil.Their EC50 values were less than 2.2 μg/ml,and EC90 values were less than 21 μg/ml.The toxicity of thiophanate-methyl with the EC50 value as 1.9008 μg/ml to Glomerella cingulata was equal to myclobutanil.But the toxicity of ziram,kresoxim-methyl and metriam were much lower than that of triazole fungicides.