Toxicity of dazomet and chloropicrin to soil-borne pathogens of ginger

The susceptibility of Pythium myriotylum Drechsler isolated from ginger to dazomet and chloropicrin was tested using the mycelium growth rate method in the bell jar.The results showed that the EC50 values of dazomet and chloropicrin were 0.284 and 0.096 mg/L,and the EC90 values were 18.106 and 0.312 mg/L,respectively.After the suspension of Ralstonia solanacearum were inoculated in sealed plates and incubating in a shaker(25 ℃,45 r/min) for 24 h,the toxicity of the two soil fumigant were appraised using the colorimetric method.The results showed that the toxicity of chloropicrin to R.solanacearum was higher than that of dazomet,with EC50 and EC90 values as 0.176 and 1.280 mg/L, however,the EC50 and EC90 values of dazomet were 1 984 and 5 701 mg/L.When fumigating the nematode suspension for 48 h in the chromatography jars,the results of microscopic examination showed that the effects of chloropicrin to Meloidogyne incognita were lower than that of dazomet,the EC50 values were 1.211 and 0.175 mg/L,and the EC90 values were 3.772 and 0.634 mg/L, respectively.