Abstract: By the methods of fumigation and contact assay, this paper determined the toxicity of four kinds of soil fumigants and six kinds of non-fumigants against Ditylenchus destructor. In the meantime, the bioactivity of the agents was evaluated by the corrected mortality rate of D. destructor after treated with the LC₅₀ dose of each agent for different time. The LC₅₀ values of soil fumigants dazomet, 1,3-dichloropropene, metham-sodium, and chloropicrin were 0.49, 0.89, 0.91, and 3.60 mg·L^-1, and those of non-fumigants emamectin benzoate, abamectin, ethoprophos, fosthiazate, aldicarb, and carbosulfan were 31.2, 48.1, 224.3, 288.4, 632.3, and 823.9 mg·L^-1, respectively. The corrected mortality rate increased with treating time. After treated with LC₅₀ dose, the inhibitory effects of dazomet, 1,3-dichloropropene, abamectin, and emamectin benzoate kept on a higher level at the time, and the corrected mortality rate did not decline after breaking away from the treatment, but the D. destructor recovered when exposed to natural state after treated with ethoprophos and aldicarb for 48h. It was suggested that dazomet, 1,3-dichloropropene, abamectin, and emamectin benzoate were the potential alternative nematicides used for the control of D. destructor.

Key words: toxicity, bioactivity, alternative nematicides, Ditylenchus destructor