吡蚜酮对烟粉虱取食干扰效应的探讨

采用甘兰叶片浸液法测定了吡蚜酮对烟粉虱Bemisia tabaci(Gennadius)成虫、卵、1龄若虫和3龄若虫的致死作用。在所测试的浓度范围(9.38～300mg/L)内,烟粉虱若虫和成虫的校正死亡率均随吡蚜酮浓度的增大而顺次显著增大。取食75～150mg/L、9.38～37.5mg/L吡蚜酮处理叶片和清水处理叶片的存活成虫个体单头蜜露量(分别为0.37～0.42、0.59～0.72、1.48mm2)间存在显著差异(P<0.05)。用EPG技术研究了吡蚜酮对烟粉虱口针刺吸的不同阶段和取食活性的影响。接触低浓度吡蚜酮(75mg/L)时,最初粉虱能够正常开始取食,但不能从韧皮部正常吸取汁液。高浓度的吡蚜酮(300mg/L)抑制了口针向植物的插入。综合上述结果,说明吡蚜酮可望成为防治番茄黄曲叶病毒病载体-烟粉虱的重要药剂之一。

Effect of pymetrozine interferes with feeding behaviour of Bemisia tabaci(Homoptera: Aleyrodidae)

We tested the mortality and LC50 of pymetrozine against whiteflies using the cabbage leaf-disc dipping method.The concentration of pymetrozine ranged between 9.38mg /L and 300mg /L and mortality was significantly dosage-dependent.There were significant differences in the honeydew quantities（0.37-0.42、0.59-0.72 and 1.48 mm2,respectively）of adults feeding on leaves dipped in 75-150、9.38-37.5 and 0 mg /L pymetrozine（P 0.05）.The effect of pymetrozine on different phases of stylet penetration and feeding activity of individual whiteflies was studied using the Electrical Penetration Graph technique（EPG）.When low-concertration pymetrozine（75 mg /L）was applied to leaves,whiteflies started feeding normally.However,after some time they withdrew their stylets from the phloem.Higher concertrations of pymetrozine（300 mg /L）inhibited stylet insertion into the plant.Therefore,pymetrozine may be one of the most effective chemicals for the control of sweet-potato whiteflies,which are vectors of tomato yellow-leaf curl viruses.