Abstract:

The indoor toxicities of avermectin and fipronil on the 3rd instar larvae of diamondback

moth \[Plutella xylostella (Linnaeus)\] and their effects on feeding of the tested

insects were studied. After Potter spraying treatment, the corrected mortality rate

caused by the 2 insecticides in all treatments increased as time flew away. But the leaf

protection rate decreased especially in the treatments with avermectin at lower

concentrations. After leaf-dipping treatment, both corrected mortality rate and leaf

protection rate in all treatments increased as time went along. In 72 h treatment with

avermectin, the corrected mortality rate was significantly lower than leaf protection

rate, except in those treatments with the concentration of 10.00 mg/L or 0.31 mg/L, the

two rates were similar. However, in the treatments with fipronil, the former was

significantly higher than the later in all treatments, except those with the

concentration of 12.50 mg/L, the two rates were also similar. The significance of leaf

protection rate in toxicity assessment of insecticides was discussed.

Key words: diamondback moth \[Plutella xylostella (Linnaeus)\], fipronil, avermectin, leaf protection rate, corrected mortality rate

摘要：

研究了阿维菌素、氟虫腈两种药剂对小菜蛾\[Plutella xylostella (Linnaeus)\]3龄幼虫的毒力及对

其取食的影响。Potter喷雾法处理后,两种农药处理中的试虫校正死亡率均随着时间的推移而逐渐升高

,但叶片保护率却有降低趋势,且在阿维菌素低浓度处理中更明显。浸叶法处理后,试虫校正死亡率与叶

片保护率均随时间的推移而升高,在阿维菌素的72 h处理中,除了10.00 mg/L、0.31 mg/L两个浓度处理

中试虫校正死亡率与叶片保护率相近外,其余均为叶片保护率显著高于校正死亡率。而氟虫腈的处理中

,则除了12.50 mg/L浓度处理中的叶片保护率与试虫校正死亡率相近外,其余均为试虫校正死亡率与叶

片保护率相近。最后讨论了叶片保护率在农药毒力评价中的意义。

关键词: 小菜蛾\[Plutella xylostella (Linnaeus)\]；氟虫腈；阿维菌素；叶片保护率；校正死亡率