(33(3):331-336)十字花科蔬菜三種鱗翅目害蟲抗藥性之探討

The imported cabbageworm, Pieris rapae Boisduval the tobacco cutworm, Spodoptera litura Fabricius; and the cabbage looper, Trichoplusia ni Hubner, were sampled from several major vegetable growing areas for the insecticide susceptibility study. For each species, susceptibilities differ among sampled populations resulted from resistance. The finding of this investigation indicated that the imported cabbageworms were free from the resistance problem and chemical control is a very effective measure for controlling this pest. The cabbage loopers are sensitive to neither mevinphos nor carbofuran and are very sensitive to the insecticidal action of synthetic pyrethroids. The test results clearly showed that resistance had developed in tobacco cutworms and the degree of resistance varied from region to region. The highest resistant ratios observed in tobacco cutworm were 63.0 for mevinphos, 79.0 for carbofuran, 13.0 for permethrin and 4.1 for fenvalerate. In general, the synthetic pyrethroids are still the most effective agents for controlling the three tested pest species, but the organophosphorus and carbamates have encountered resistance problem in both cabbage loopers and tobacco cutworms. 本省歷年來蔬菜之蟲害保護工作多仰賴殺蟲劑，以致近年來害蟲相較趨於單純，但使用藥劑時，常有效果減退之現象發生。查其原因，可能係害蟲已對常用殺蟲劑產生不同程度之抗藥能力，小菜蛾，Plutella xylostella ( L. ) ，即是一已經證實且抗藥問題極嚴重之十字花科蔬菜害蟲。此外，在十字花科蔬某上經常發生的鱗翅目害蟲尚有紋白蝶， Pieris rapae Boisduval 、斜紋夜盜 Spodoptera litura Fabricius 及擬尺蠖Trichoplusia ni Hubner。為暸解後三種害蟲是否亦對殺蟲劑產生某種程度之抗藥力，乃進行本研究。 研究結果發現，本省各地採得之紋白蝶對四種常用殺蟲劑，美文松（ Mevinphos ）、加保扶（Carbofuran ）、百滅寧（ Permethrin ）及芬化利（ Fenvalerate），均極為敏感，無抗藥性產生之跡象，因此利用化學藥劑防治紋白蝶，仍為經濟可行而無抗藥性顧慮之防治方法。而擬尺蟆則對美文松、加保扶均不甚敏感，根據美、加地區之試驗結果報導，上述兩種藥劑對擬尺蠖之防治效果亦不甚良好；所測得之芬化利及百減寧對擬尺蠖則無優良殺除效果。就斜紋夜盜而言，在所採得樣品中已明顯地發現，某些蔬菜密集生產地區之斜紋夜盜已經對常用殺蟲劑產生極高之抗藥性，溪湖地區即為明顯之例證，該樣品較敏感品系對加保扶、美文松之抗藥力分別高出 79倍及 63 倍，對合成除蟲菊精類殺轟劑亦有輕微之抗藥性。斜紋夜盜對不同殺蟲劑產生之抗藥程度，依地區有甚大之差異，但一般而言除蟲菊精類仍有相當好的防治效果；約有半數取樣地區之斜紋夜盜已對美文松產生中等程度以上之抗藥性；而加保扶之防治效果已明顯地消退。本研究之結論為：暫時使用合成除蟲菊精類殺蟲劑，仍為防治此三種鱗翅目害蟲之通用辦法；若採用有機磷劑或氨基甲酸鹽劑作為防治藥劑時，必須密切注意該地區此等害蟲抗藥性之發展