成蟲飼料添加有機磷類殺蟲劑對瓜實蠅〔Bactrocera cucurbitae（Coquillett）〕（Diptera：Tephritidae）之毒效測試

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.