吡虫啉与多杀菌素混配剂对韭菜迟眼蕈蚊幼虫的室内毒力测定

摘要

为了筛选可用于韭菜迟眼蕈蚊幼虫防治的杀虫剂混剂,测定了吡虫啉与多杀菌素混配剂对韭菜迟眼蕈蚊幼虫的室内毒力.使用胃毒及触杀联合毒力的室内生物测定法,测定了吡虫啉与多杀菌素以1∶5,1∶10,1∶20及1∶40等4个浓度比例组成的混剂对韭菜迟眼蕈蚊3龄幼虫的室内毒力,并计算了相应的共毒系数.与吡虫啉和多杀菌素对韭菜迟眼蕈蚊3龄幼虫的LC50分别是11.68和92.21mg/L相比,吡虫啉与多杀菌素以1∶5,1:10,1∶20及1∶40等4个浓度比例组成的混剂对韭菜迟眼蕈蚊3龄幼虫的室内毒力LC50是12.30、8.14、5.39和9.29mg/L.共毒系数表明吡虫啉与多杀菌素以1∶5,1∶10,1∶20及1∶40浓度比例组成的4种混剂对韭蛆的毒力均表现出了增效作用.其中以1∶20浓度比组成的混剂具有最大的共毒系数1 287.58.吡虫啉与多杀菌素以1∶20浓度比组成的混剂具有最大的共毒系数,对韭蛆幼虫的毒力也最高,可用于韭菜迟眼蕈蚊幼虫的防治.%To select insecticides mixtures for controlling the larvae of Bradysia odoriphaga Yang et Zhang (B.odoriphaga) efficiently,the toxicity of mixtures of imidacloprid and spinosad to the larvae of Bradysia odoriphaga Yang et Zhang were determined.The combined topically and orally toxicities of mixtures of imidacloprid and spinosad,at concentration ratios of 1 ∶ 5,1 ∶ 10,1 ∶ 20and 1∶ 40,to the third instar larvae of B.odoriphaga,were determined in the laboratory bioassay.Meanwhile,the co-toxicity coefficients of these mixtures were also calculated.The LC50 of mixtures of imidacloprid and spinosad,at concentration ratios of 1 ∶ 5,1 ∶ 10,1 ∶ 20 and 1 ∶ 40,to the third instar larvae of B.odoriphaga,is 12.30,8.14,5.39 and 9.29m g/L,while the LC50of imidacloprid and spinosad is 11.68 and 92.21mg/L,respectively.The co-toxicity coefficients of these four mixtures showed that all the four mixtures of imidacloprid and spinosad exhibited synergistic effects on the toxicity to the third instar larvae of B.odoriphaga.The mixtures of imidacloprid and spinosad at concentration ratios of 1∶ 20 exhibited the highest co-toxicity coefficient of 1 287.58.The mixture of imidacloprid and spinosad at concentration ratio of 1 ∶ 20 exhibited both the highest co-toxicity coefficient and the highest toxicity to the larvae of B.odoriphaga,and could be used in the control of B.odoriphaga.