瘤野螟（Cnaphalocrocis medinalis）對賽洛寧及培丹抗藥性及生化抗性機制之探討

Insecticides resistance and biochemical resistance mechanism to cyhalothrin and cartap in rice leaf folder Cnaphalocrocis medinalis

"瘤野螟（Cnaphalocrocis medinalis（Guenée））在分類上屬於鱗翅目（Lepidoptera）、草螟科（Crambidae），近年來在台灣成為二期稻的重要害蟲。目前防治此害蟲的方法以化學藥劑為主，但國外已有研究報告指出瘤野螟對約16種不同作用機制的殺蟲劑的抗藥性有上升的現象。本研究首先分析屏東長治及台南後壁兩地區的瘤野螟對八種殺蟲劑之抗藥性，結果顯示兩個族群皆對賽洛寧產生抗性，而長治族群則是在2014到2015年間對培丹抗性有上升的現象。為了解瘤野螟對賽洛寧及培丹產生的生化抗性機制，因此進行協力劑測試以確認是否有解毒酵素參與此害蟲對擬除蟲菊類殺蟲劑的代謝抗性，結果顯示在賽洛寧處理方面，兩族群在添加協力劑Piperonyl butoxide（PBO）後協力比分別高達258及606.8；添加Diethyl maleate（DEM）後協力比分別為1.743及5.389；添加Triphenyl phosphate（TPP）後協力比分別為2.205及6.911。在培丹處理方面，只有長治族群在添加PBO後有協力效果（協力比為3.636）。進一步分析不同濃度之賽洛寧及培丹處理下瘤野螟體內三種解毒酵素的活性變化，首先在賽洛寧方面，結果顯示長治族群的細胞色素P450單加氧酶（Cytochrome P450 monooxygenase, P450）活性只有在處理賽洛寧1μg/ml時才顯著提高，然而酯酶（Esterase, EST）和麩胱甘肽轉移酶（Glutathione-S-transferase, GST）活性則是隨著賽洛寧濃度而提高；相較之下，後壁族群P450活性隨著藥劑濃度提高，但EST活性則是皆顯著降低。在培丹方面，結果顯示後壁族群的P450和EST兩者活性皆顯著降低。依據上述結果推測三種解毒酵素皆與瘤野螟代謝賽洛寧有關，其中以CYP450為主要代謝賽洛寧和培丹的解毒酵素，而且由PBO協力測試、P450解毒酵素活性結果皆顯示出與兩族群對賽洛寧的抗性程度差異有關。"

"In recent years, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) become an important pest on the rice of second phase in Taiwan. Application of insecticides was the main method to control this insect, but the resistance to various kinds of insecticides has been documented in Taiwan and other countries. This study investigated the resistance of C. medinalis from Changjhih and Houbi to eight insecticides. The results showed that both populations developed resistance to cyhalothrin, and the Changjhih population showed additional resistance to cartap. The synergist test was used to determine whether detoxification enzymes were involved in the metabolic resistance to cyhalothrin and cartap. When C. medinalis of Changjhih and Houbi populations were treated with cyhalothrin and three synergists individually, these two populations synergistic ratio of 285 and 606.8 for piperonyl butoxide (PBO), 1.74 and 5.4 for Diethyl maleate (DEM), 2.21 and 7.53 for Triphenyl phosphate (TPP), respectively. In addition, synergism of cartap and PBO was observed in Changzhi population, and the synergistic ratio was 3.64. Further analysis about detoxification enzymes activity treated with cyhalothrin or cartap at different concentrations for C. medinalis, biochemical assay showed cytochrome P450 (P450) activity increased significantly for Changzhi population after exposure 1 μg/ml cyhalothrin, however, the degree of Esterase (EST) and Glutathione-S- transferase (GST) activity increased at higher concentration of cyhalothrin. Besides, elevation of CYP450 activity of Houbi population with the concentration increasing, but EST activity was significantly reduced. The result showed P450 and EST activity significantly decreased in Houbi population after exposure to cartap. Above results concluded all three kinds of detoxification enzymes are involved in metabolism of cyhalothrin for C. medinalis, and cytochrome P450 is the major detoxification enzyme in the metabolism of cyhalothrin and Cartap. Overall results showes degrees of difference of cyhalothrin resistance from two poplution might appear correlation with synergistic test by the PBO."