(62(4):372-381) Lethal Effects of Organophosphates Mixed with Adult Food against the Melon Fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae)

本研究利用8 種有機磷類殺蟲劑分別依5 種比例添加於成蟲飼料中，評估其對瓜實蠅 [Bactrocera cucurbitae (Coquillett)] 的毒殺效果。試驗結果顯示隨著藥劑濃度的升高，瓜實蠅的死亡率也隨著升高。僅供含毒食餌之非選擇性試驗結果顯示，含大滅松的食餌對瓜實蠅有較佳的毒殺效果，濃度1/2000 (v/v) 時大滅松食餌在24 h 後即可導致85% 的瓜實蠅死亡率，在48 h 後則達98%，而含佈飛松的食餌對瓜實蠅的毒殺效果最差。同時供給含毒及無毒食餌的選擇性試驗結果顯示，所有供試餌劑中仍以含大滅松的食餌對瓜實蠅的毒殺效果最高，而含撲滅松或馬拉松的食餌對瓜實蠅的毒殺效果最低。殘效試驗結果顯示，賽達松食餌持效性在所有供試藥劑中最長，濃度1/100 經2 wk 後瓜實蠅死亡率仍可維持超過80%。綜合而言，供試藥劑中之陶斯松、大滅松、芬殺松、賽達松與普硫松添加於餌劑對瓜實蠅有良好的毒殺效果，可作為未來瓜實蠅誘殺餌劑之添加農藥的參考。 The study was conducted to evaluate effects of five ratios of eight organophosphates in adult food on the mortality of the melon fly, Bactrocera cucurbitae (Coquillett). Higher ratios of insecticides resulted in increasing melon fly mortalities. As there were no non-insecticide food baits provided for melon fly's choice (no-choice test), baits mixed with dimethoate caused higher mortalities compared to other insecticides tested on the melon flies. Dimethoate baits at a concentration of 1/2000 (v/ v) killed approximately 85% of the flies tested at 24 h, while it caused 98% mortality at 48 h. On the other hand, the profenofos bait was least effective to the melon fly. In a non-insecticide bait provided together with an insecticide bait to the melon flies for choice (choice test), dimethoate bait still caused the highest mortalities to the flies tested, while fenitrothion and malathion baits resulted in the lowest ones. Melon fly mortalities were higher in the no-choice tests than the choice. Phenthoate bait maintained the highest residual toxicity among all of the baits tested. This bait at a concentration of 1/100 after two weeks of exposure in the greenhouse still caused over 80% of mortalities. Collectively, this study showed that chlorpyrifos, dimethoate, fenthion, phenthoate and prothiofos elicited high toxicity to the melon fly while incorporated into the adult food, and were potential to be considered as the insecticide additives in melon fly baits