3种化学杀虫剂对筛胸梳爪叩甲幼虫的毒力测定

  目的  为明确3种化学杀虫剂对筛胸梳爪叩甲Melanotus ribricollis幼虫的防治效果，选择最适杀虫剂。  方法  采取拌土法对幼虫阶段筛胸梳爪叩甲进行室内毒力测定。选取了质量分数为5.0%的辛硫磷颗粒剂、0.5%的氟虫腈粉剂20.0%的氯虫苯甲酰胺悬浮剂3种药剂，分别以5个质量分数梯度均匀拌入按照1∶2的体积比混合的砂子和竹林土中，以喷洒清水作为空白对照，24 h后观察不同药剂处理后筛胸梳爪叩甲的死亡率。  结果  3种化学杀虫剂对筛胸梳爪叩甲均有一定的毒杀效果，毒力由高到低依次为5.0%辛硫磷、0.5%氟虫腈、20.0%氯虫苯甲酰胺，其中5.0%辛硫磷毒力最高，致死中质量分数（LC₅₀）为0.190 0 g·kg?1，其次为0.5%氟虫腈，LC₅₀为0.950 0 g·kg?1，而20.0%氯虫苯甲酰胺毒力最低，LC₅₀为1.820 0 g·kg?1。  结论  根据毒力、毒性和防治成本等综合因素考虑，5.0%辛硫磷颗粒剂和0.5%氟虫腈粉剂均适合防治竹林害虫筛胸梳爪叩甲。表2参27

Indoor prevention and toxicity test of three chemical insecticides against Melanotus ribricollis

  Objective   In order to clarify the control effect of different chemical insecticides on the larvae of the Melanotus cribricollis, a virulence test was carried out on the larvae stage for the present study.   Method   With 5.0% phoxim granules, 0.5% fipronil powder and 20.0% chlorantraniliprole suspension selected and mixed into sand and bamboo forest soil in a 1∶2 ratio with 5 concentration gradients, to observe the mortality rate of M. cribricollis after 24 hours in contrast with a control group where water was sprayed without any insecticides.   Result   The three selected chemical insecticides all have certain control effects on M. cribricollis, with the control effect from strong to weak: 5.0% phoxim＞0.5% fipronil＞20.0% chloranthrene Benzoamide. It was found that the 5.0% phoxim has the best control effect, with an LC₅₀ of 0.190 0 g·kg?1, followed by 0.5% fipronil, with an LC₅₀ of 0.950 0 g·kg?1, and 20.0% chlorantraniliprole which has the weakest control effect with a LC₅₀ of 1.820 0 g·kg?1.   Conclusion   With control effectiveness, toxicity and control costs taken into consideration, 5.0% phoxim Phosphorus granules and 0.5% fipronil are suitable for the control of bamboo forest pests M. cribricollis, yet with the need to further explore the application methods and relevant technologies of forest chemicals. Ch, 2 tab. 27 ref.]