几种常用杀虫剂在洋葱上的残留降解动态

研究了毒死蜱、敌百虫和氯氰菊酯不同施药方法在洋葱上的残留降解动态。结果表明，毒死蜱喷雾在洋葱上的残留期较长，而采用药液灌根法施药，其残留期较短，残留量较少，即使在施药后第1d取样检测，残留量仍远远低于国家规定标准；敌百虫采用灌根法施药，在葱头中的残留量很低，施药后第1d取样检测，其残留量远远低于国家规定标准，这2种药剂可以作为防治地下害虫的良好杀虫剂。氯氰菊酯采用喷雾法施药，即使在施药后第1d，也检测不到农药残留，因此，是一种良好的喷雾用杀虫剂。

Residue degradation dynamics of several insecticides in onion

Degradation dynamics of chlorpyrifos, trichlorphon, and cypermethrin residues in onion were investigated. Chlorpyrifos residues showed relatively long residual when sprayed onto onions. However, residues were relatively short-lived and residue levels were low when applied by root drench, resulting in levels significantly lower than Chinese national standards even when sampled 1 d after application. Trichlorphon residue levels sampled 1 d after application were much lower than national standards when the pesticide was applied to onions by root drench. These two insecticides are effective in controlling soil-borne insect pests. Residues of cypermethrin were undetectable even when sampling 1 d after spray application. Thus, this insecticide is especially suitable for spray application.