甲维盐·毒死蜱及其复配对小菜蛾的毒力分析

Toxicity analysis of emamectin benzoate and chlorpyrifos as well as their mixtures on Plutella xylostella

以小菜蛾(Plutella xylostellar)3龄幼虫为试虫测定了甲胺基阿维菌素苯甲酸盐、毒死蜱及两者5种不同配比的复配剂的毒力,测定结果建立了“时间—剂量—死亡率”模型。根据模型分析结果,甲胺基阿维菌素苯甲酸盐与毒死蜱混配后增效显著。在5种配比中以甲氨基阿维菌素苯甲酸盐∶毒死蜱=1∶74为最佳配比,其24-60 h 4个时段的共毒系数在334到550之间;与单剂相比,该配比明显提高了24 h时段内和48-60 h时段的杀虫率。

The toxicity of emamectin benzoate, chlorpyrifos as well as their mixtures at different ratios to 3rd Plutella xylostella larvae was determined. Based on the bioassay results, the ＂time-dose-mortality model＂ was set up. The results showed that significant synergism effect could be found after mixing emamectin benzoate with chlorpyrifos and the greatest synergism took place at the ratio of 1： 74. The cotoxicity coefficients （ CTC ） of the mixture were ranged from 334 to 550 at the interval of 24 -60 h after treatment. Compared with the single chemical, mixing at this ratio could significantly increase the toxicity effect on Plutella xylosella within 24 or 48 to 60 h after treatment.