不同方法测定四氯虫酰胺和虫螨腈对小菜蛾生物活性的温度系数

Temperature coefficient in bioactivity of tetrachlorantraniliprole and chlorfenapyr to Plutella xylostella by different bioassay methods

[目的]评价不同生物活性测定方法对杀虫剂温度效应的影响。[方法]分别采用食料浸渍法、浸虫法和点滴法测定四氯虫酰胺和虫螨腈对小菜蛾的生物活性,分析了其随温度变化的趋势。[结果]对于正温度效应杀虫剂四氯虫酰胺,采用食料浸渍法时其活性随温度的升高(15~35℃)增加了99.15倍,呈强正温度效应,而另外2种方法表现为弱正温度效应。食料浸渍法测定时生物活性不受温度影响的虫螨腈,采用浸虫法和点滴法测定时,却表现出了+5.50和+3.50的弱温度效应。采用食料浸渍法时四氯虫酰胺和虫螨腈35℃时的温度系数分别为+99.15和+1.58,差异显著,而采用浸虫法和点滴法时2者温度系数相近。[结论]测定方法的选择显著地影响了正温度系数药剂四氯虫酰胺对小菜蛾生物活性的温度系数,而无温度效应药剂虫螨腈对小菜蛾生物活性没有受到显著影响。

[Aims]To evaluate the influence of different bioassay methods on the insecticide temperature effect.[Methods]The toxicity of tetrachlorantraniliprole and chlorfenapyr against Plutella xylostella were determined by leaf-dipping method,insect-dipping method and topical application method,respectively,and the temperature-dependent trends were analyzed.[Results]For positive temperature coefficient insecticide tetrachlorantraniliprole,a 99.15-fold increase in toxicity with increasing temperature(15-35℃)was observed with the leaf-dipping method,showing a strong positive temperature effect,while the other two methods showed a weak positive temperature effect.Chlorfenapyr,whose biological activity was not affected by temperature in leaf-dipping assay,showed a weak positive temperature effect of+5.50 and+3.50 when using the insect-dipping and topical application method.When use leaf-dipping method,the temperature coefficients of tetrachlorantraniliprole and chlorfenapyr were+99.15 and+1.58 at 35 C,respectively,with significant differences.In contrast,the temperature coefficients of the two insecticides against P.xylostella were similar when using the insect-dipping and topical application methods.[Conclusions]The choice of bioassay method significantly affected the temperature coefficient of tetrachlorantraniliprole,which had a positive temperature effect to diamothback moth,whereas temperature independent pesticide,chlorfenapyr,was not significantly affected on the bioactivity.