土荆芥精油对小菜蛾幼虫表皮的渗透促进作用

Effects of Chenopodium ambrosioides Essential Oil on Exoskeleton and Insecticide Permeation of Plutella xylostella Larvae

【目的】了解土荆芥精油对杀虫剂的渗透促进作用,明确土荆芥精油对小菜蛾幼虫透皮吸收的效果。【方法】采用扫描电镜观察施用土荆芥精油后小菜蛾表皮超微结构的变化,并利用气质联用仪测定和分析土荆芥精油对杀虫剂透皮吸收量的影响。【结果】与蒸馏水对照和丙酮处理相比,土荆芥精油或氮酮处理后,小菜蛾表皮蜡质层结构出现明显的结构性损伤,刺状突起排列变得较为松散,刺状突起变得平滑,刺状突下部变得褶皱或开裂。随着时间的延续,土荆芥精油对3种杀虫剂的透皮吸收量和渗透率均大幅增加;处理24 h后,土荆芥精油处理的氟虫腈渗透率达99.34%,显著高于氟虫腈单剂(55.12%)。【结论】土荆芥精油与氮酮处理对小菜蛾幼虫表皮的影响相似,土荆芥精油对敌百虫、氟虫腈、毒死蜱都具有很好的渗透促进作用。本研究结果可为利用土荆芥精油促进有机磷、苯基吡唑类和硫代磷酸酯类杀虫剂的透皮作用提供理论依据。

【Objective】Effects of Chenopodium ambrosioides(L.)essential oil on the exoskeleton structure and the insecticide permeation of Plutella xylostella(Linn.)were studied to determine if the insecticidal efficacy on the moth could be improved by treatment with the essential oil.【Method】Changes on the exoskeleton ultrastructure of diamondback moth(DBM,P.xylostella)larvae upon treatment of the wormseed essential oil(WEO)or Azone(laurocapram)were examined under a scanning electron microscope.The permeabilities of subsequent separate application of 3 insecticides into the larvae by percutaneous absorption and penetration were determined by GC-MS.【Result】Using distilled water as control and acetone for comparison,WEO or Azone treatment produced significant alterations on the spines and the epicuticle waxy layer structure of DBM.The hair-like piles became sparse,the cuticle surface smoothed,and the lower part of spines folded or cracked.Prolonged treatment significantly increased the penetration of the 3 subsequently applied insecticides through DBM exoskeleton.In 24h,the transdermal absorption rate of fipronil had reached 99.34%,which was significantly higher than control(55.12%).【Conclusion】The enhancing effect of WEO pretreatment on the transdermal penetration of subsequently applied insecticide on DBM was similar to that of Azone.The enhancement on fipronil penetration was also found on trichlorfon and chlorpyrifos permeation.Similar results were,therefore,expected for the cases involving other organophosphorus,phenylpyrazole,and thiophosphate insecticides.