虱螨脲对小菜蛾生存、化蛹和羽化的影响

为全面了解虱螨脲对小菜蛾的杀虫作用，采用浸叶法测定虱螨脲对小菜蛾3龄幼虫毒力的同时，观察了虱螨脲对小菜蛾幼虫存活、化蛹和羽化等的影响。结果表明，虱螨脲对小菜蛾具有生物活性高、用量低、作用缓慢但药效持续时间长等特点。尽管0.01953125、0.0390625、0.078125、0.15625和0.3125 mg/L这5个浓度处理48 h死亡率与对照相比没有显著差异，但蛹前累计死亡率，除最低浓度(0.01953125 mg/L)外，其他测定浓度均显著低于对照。同样，除最低浓度外，其余测定浓度的化蛹率显著低于对照；此外，所有测定浓度的羽化率均显著低于对照，且都表现为浓度越高，差异越显著。但所有测定浓度对小菜蛾幼虫的蛹重没有显著影响。

Effect of Lufenuron on Survival, Pupation and Adult Emergence of the Third Instar Larvae of Plutella xylostella

Together with the indoor toxicity test of lufenuron to the third instar larvae of Plutella xylostella （Lepidoptera： Yponomeutidae）, the effect of lufenuron on survival, pupation and adult emergence of the tested insect was studied to fully understand its biological activities. The results showed that lufenuron had characteristics of high biological activity at low dosage, slow effect but lasting efficacy on P. xylostella. The mortalities after 48 h at 5 concentrations （0.01953125, 0.0390625, 0.078125, 0.15625 and 0.3125 mg/L） were not significantly difference compared with control, but the mortalities of accumulated before pupation at the rest concentrations were significantly lower than control, except the lowest concentration （0.01953125 mg/L）. Similarly, the pupation rates at the rest concentrations were also significantly lower than control, except the lowest concentration. Besides that, the adult emergence rates at all tested concentrations were significantly lower than control, and expressed the higher the concentration, the more significant difference. However, the pupal weight between all the treatment groups and the control group were not significantly different.