南黃薊馬對不同作用機制殺蟲劑的感受性與抗性機制分析

Susceptibility and resistance mechanisms to different modes of insecticides in the melon thrips (Thrips palmi)

"南黃薊馬（Thrips palmi）為台灣瓜類及茄子上的重要害蟲，目前施用殺蟲劑是主要防治方式。本研究為瞭解台灣地區南黃薊馬對不同作用機制殺蟲劑的感受性，進行三個地區之南黃薊馬對第滅寧、可尼丁、滅賜克、克凡派及賜諾特等五種不同作用機制藥劑的感受性分析。結果顯示第滅寧及可尼丁對南黃薊馬的LC90皆遠大於植保手冊上登記的濃度，由此推論試驗地區的南黃薊馬對除蟲菊類和新尼古丁類殺蟲劑可能已產生抗性。生化代謝解毒是昆蟲產生抗藥性的主要機制之一，利用添加Piperonyl butoxide（PBO）、Diethyl maleate（DEM）、Triphenyl phosphate（TPP）等三種協力劑進行測試，結果顯示在第滅寧及可尼丁中添加PBO後協力比最低達6倍以上，因此推測細胞色素P450（cytochrome P450, CYP450）參與南黃薊馬對第滅寧及可尼丁的解毒作用；第滅寧添加TPP後南黃薊馬的協力比最低4倍，因此推測酯酶（Esterases, EST）參與南黃薊馬對第滅寧的解毒作用。當第滅寧同時添加PBO及TPP後，CYP450及EST活性皆有下降的趨勢，顯示這兩類酵素同時參與南黃薊馬對第滅寧的解毒作用。另一方面，本研究解析三地區南黃薊馬族群中鈉離子通道（Sodium channel）的DNA序列，在所測試的樣本中均帶有（T929I）氨基酸的點突變序列，推測高頻率的T929I點突變可能是南黃薊馬對第滅寧產生高抗性的主要原因。"

"The melon thrips, Thrips palmi, is a major pest of melons and eggplant in Taiwan. Spraying insecticide is main control practice. This study is to understand susceptibility of melon thrips to different MoA insecticides in Taiwan. Melon thrips T. palmi was collected from three populations on eggplant, and then the toxicity of recommended insecticides (deltamethrin, clothianidin, methiocarb, chlorfenapyr, spinetoram) were tested to these populations of melon thrips. Our result showed that LC90 values of these three melon thrips populations are much larger than the recommended concentration of deltamethrin and clothianidin. Therefore, melon thrips from these areas might be resistant to neonicotinoids and pyrethroids. Biochemical metabolic detoxification is one of resistance mechanisms for insect to pesticides. Synergists of piperonyl butoxide (PBO)、diethyl maleate (DEM)、triphenyl phosphate (TPP) was used with deltamethrin and clothianidin to measure the synergist ratio in order to identify which type of detoxification enzyme is involved in metabolic resistance of melon thrips. Our results showed that deltamethrin and clothianidin with PBO can result in significant synergism of more than six times in three tested populations of melon thrips, which implied the involvement of cytochrome P450 to the resistance against deltamethrin and clothianidin. In addition, when adding deltamethrin with TPP synergism was observed at least four times of synergism, which implied esterases are involved, too. Besides, our study show melon thrips from three populations have also the point mutation (T929I) of sodium channel with frequency up to 100%. This phenomenon had confirmed that the high degree of resistance to pyrethroids also contributed with the target site point mutation of sodium channel."