杀虫剂对新入侵海南草地贪夜蛾种群幼虫的毒力

草地贪夜蛾是2019年1月新入侵我国云南的重大农业害虫,4月首次在海口玉米田中剥查发现该虫。草地贪夜蛾严重威胁到海南本地的鲜玉米生产,筛选出具有较高毒力水平的化学药剂防治该虫迫在眉睫。本文采用浸叶法测定了15种杀虫剂对草地贪夜蛾幼虫的毒力。实验结果表明,采用较低浓度的甲维盐（5 mg/L,24 h）和多杀菌素（5 mg/L,24 h）,以及较高浓度氯虫苯甲酰胺（50 mg/L,72 h）和辛硫磷（100 mg/L,72 h）时,对草地贪夜蛾幼虫的致死率达100%,这4种杀虫剂在24 h的LC₅₀分别为0.28、0.31、9.77和11.7 mg/L;其他种类杀虫剂如灭多威、吡丙醚、氟虫腈、啶虫脒、阿维菌素、高效氯氰菊酯和虱螨脲,在100 mg/L浓度水平下,72 h对草地贪夜蛾幼虫的校正死亡率分别为100%、96.67%、88.33%、86.11%、81.67%、80.83%和80.09%。表明了可选用甲维盐、多杀菌素、氯虫苯甲酰胺和辛硫磷作为主要成分的杀虫剂,并组合其他种类杀虫剂,作为当前防治草地贪夜蛾幼虫主要防治药剂。

Toxicity of Insecticides Against Larvae of Spodoptera frugiperda Population,A New Invasive Pest

The fall armyworm, Spodoptera frugiperda, first invaded Yunnan, China, in January 2019, is a notorious agricultural pest insects. It was first founded on maize in Haikou city in April, and poses a serious threat to the production of fresh eating maize. It is urgent to screen out high toxicity insecticides for controlling this pest. By leaf dipping method, the toxicities of 15 insecticides to larvae of S. frugiperda were tested under laboratory conditions. The results showed that at the relative lower concentration of emamectin benzoate (5 mg/L, 24 h) and spinosad (5 mg/L, 24 h), and relative higher concentration of chlorantraniliprole (50 mg/L, 72 h) and phoxim (100 mg/L, 72 h) have 100% contact toxicity to larvae of S. frugiperda. Their 50% lethal concentration (LC₅₀) at 24 h is 0.28, 0.31, 9.77 and 11.7 mg/L, respectively. Other insecticides such as methomy, pyriproxyfen, fipronil, acetamiprid, abamectin, beta-cypermethrin and lufenuron, at concentration of 100 mg/L with 72 h, have 100%, 96.67%, 88.33%, 86.11%, 81.67%, 80.83%, and 80.09% contact toxicity to larvae of S. frugiperda. It recommended to use emamectin benzoate, spinosad, chlorantraniliprole, and phoxim as the main ingredients, as well as combined with other above mentioned insecticides, for controlling of larvae of S. frugiperda.