几种药剂对稻纵卷叶螟的毒力测定

目的]测定几种常用药剂对稻纵卷叶螟的毒力,为控制稻纵卷叶螟的危害提供依据。方法]将供试7种药剂稀释成5个系列浓度,3龄中期幼虫为试材,浸虫法测定,处理后48 h(氟铃脲96 h)调查试虫死亡情况。结果]杀虫单对水稻稻纵卷叶螟毒力最低,LC50为306.624 2 mg/L,毒力最高的为阿维菌素,LC50达到了0.221 0 mg/L,氟虫腈对稻纵卷叶螟的LC50为7.237 5 mg/L,仅次于阿维菌素。7种药剂对稻纵卷叶螟毒力的高低顺序为阿维菌素>氟虫腈>毒死蜱>氟铃脲>三唑磷>丙溴磷>杀虫单。1.8%阿维菌素乳油用量8.1 g(a.i)/hm2和40%丙溴磷乳油480 g(a.i)/hm2,药后10 d防效分别达到86.68%和81.72%。结论]丙溴磷、阿维菌素、氟虫腈、氟铃脲对稻纵卷叶螟的防效均较好,混配使用可达到理想的防治效果。

Toxicity Determination of Several Insecticides against Cnaphalocrocis Medinalis(Gunenée)

Objective] The study aimed to determine the toxicity of several insecticides against Cnaphalocrocis medinalis(Gunenée),and provide a base for controlling Cnaphalocrocis medinalis(Gunenée).Method] With the 3th instar larvae of Cnaphalocrocis medinalis(Gunenée) as tested larva,seven kinds of insecticides were diluted as five series of concentration,the mortality of the tested insects were investigated after treating by insect-soaking method for 48 h(96 h treated with Monosultap).Result] Monosultap had a lowest toxicity to C.medinalis with LC50 of 306.624 2 mg/L.Avermectins had a highest toxicity with LC50 of 0.221 0 mg/L and Fipronil's LC50 was 7.237 5 mg/L,being only lower than Avermectins'.Based on their toxicity to C.medinalis,the tested 7 insecticides were arranged in decreasing order as Avermectins > Fipronil > Hexaflumuron > Profenofos > Chlorpyrifos > Triazophos > Monosultap.Control efficacy of 1.8% Avermectins EC at 8.1 g(a.i) /hm2 and 40% Profenofos EC at 480 g(a.i) /hm2 was 86.68% and 81.72% resp.after applying insecticides for 10 d.Conclusion] Profenofos,Avermectins,Fipronil and Hexaflumuron had a good control efficacy in the field,and applying their mixtures could have a better control efficacy against C.medinali.