苯酰基脲类杀虫剂防治稻纵卷叶螟的研究

EXPERIMENTS ON THE APPLICATION OF BENZOYLPHENYL UREA INSECTICIDES IN CONTROLLING RICE LEAF FOLDER

在防治稻纵卷叶螟小区试验中,苯酰基脲类杀虫剂定虫隆(IKI-7899,chlorfluazuron)每亩5克有效成分的剂量防治效果达100％;每亩1.25克的防治效果略高于每亩25克甲胺磷。不同施药期试验结果表明:于卵盛孵期施药效果最好,卵高峰期次之,三龄期施药效果最差。在大区试验中,以生命表方法评价了定虫隆和甲胺磷对稻纵卷叶螟整个世代的综合效应。每亩施用2.5克有效成分的定虫隆,稻纵卷叶螟的种群增长指数Ⅰ=0.0000466,施用25克甲胺磷,Ⅰ=0.5593,不施药田Ⅰ=2.98。定虫隆对田间主要捕食性天敌蜘蛛较安全。灭幼脲Ⅰ号以实用剂量施用不能有效防治稻纵卷叶螟。

Two benzoylphenyl ureas were tested for controlling the rice leaffolder (Cnaphalocrocis medinalis) in the field.Diflubenzuron (Dimilin)was insufficant to get available results with practical doses.Excellentresults were found with IKI-7899 (chlorfluazuron).100% control wasobtained when 75 g(a.i.)/ha.of this insecticide was sprayed,37.5 and18.75 g(a.i.)/ha.was also better than 375 g(a.i.)/ha.of the conven-tional insecticide methamidophos.For the timing of application of IKI-7899,early 1st instar larval period was the best,next was the eggperiod.During the 3rd instar larval period,poor control resulted.Life tables of leaf folder were used to evaluate the comprehensiveeffectiveness of insecticides on the whole generation of this pest insectin large plot trials.In the plot treated with IKI-7899(37.5 g(a.i.)/ha.),the insect population had a I near zero,in the plot treated withmethamidophos (375 g(a.i.)/ha.) ,I=0.463,and in untreated plot,I=2.11.IKI-7899 was found to be safe to the spiders,the main groupof natural enemies in the paddy field,but application of methamido-phos reduced their numbers in the field.