杀虫剂对韭菜迟眼蕈蚊毒力与药效相关性研究

Study on Correlationship Between Toxicity and Field Control Effect of Insecticides to Bradysia odoriphaga

韭菜迟眼蕈蚊Bradysiaodoriphaga以幼虫蛀食韭菜根茎造成危害,为使毒力测定方法与田间幼虫受药方式具有较高程度的一致性,建立了胃毒触杀联合毒力测定法,利用该方法测定了分属三个类别的4种杀虫剂即毒死蜱、辛硫磷、丙硫克百威、吡虫啉对韭菜迟眼蕈蚊3龄幼虫的毒力,以辛硫磷为标准药剂,毒死蜱、吡虫啉和丙硫克百威的相对毒力倍数分别为10.36、2.61和2.30。田间达到50%防效所需药剂浓度以辛硫磷为最高,毒死蜱、吡虫啉和丙硫克百威对辛硫磷的防效比值分别为9.58、1.88和2.05。胃毒触杀联合毒力法测得的药剂毒力高低排序及相对毒力倍数与田间小区试验结果基本一致,与常规的单一触杀法比较,该法测定结果的重现性好,并且与田间药效试验结果相关性高。同时讨论了不同操作方法对室内毒力测定结果的影响。

A contact & stomach method was established. Using this method the toxicities of four insecticides, chlorpyrifos, phoxim, benfuracarb and imidacloprid to 3rd-instar larvae of Bradysia odoriphaga were determined. With phoxim as a standard insecticide,the relative toxicities of chlorpyrifos, imidacloprid and benfuracarb were 10.36,2.61 and 2.30, their field effect ratios were (9.58),1.88 and 2.05, respectively. The results showed that the accordance of the toxicity (turn) of 4 insecticides obtained by contact & stomach method in lab with the control effect turn (obtained) in field trial was better than that of contact method toxicity turn with field effect. The precision of contact & stomach method was also high. At last, the influence on toxicity of (different) treatment methods to larvae was compared and discussed.