(45(4):422-435)Instability of the Currently Used Poison Baits for the Oriental Fruit Fly and Melon Fly－The Study on Decomposition of Naled and Cuelure

東方果實蠅誘殺劑，含毒甲基丁香油，在1992─93年成品發生褐變，以致藥效消退。經研究發現，主要原因來自誘殺劑中之乃力松受光分解，脫溴成為二氯松後，再分解為無效成份，經試以茶色瓶遮光，即可大幅提昇誘殺劑之穩定性；誘殺劑中之甲基丁香油則無明顯分解情形。瓜實蠅誘殺劑中之乃力松亦有類似的受光分解問題，而另一主成份克蠅則有自發性的水解現象，似與常態下室溫及光線之變化無關。克蠅經解離乙酸根後形成p-phenyl-2-butanone，而失去誘集瓜實蠅之作用。The insecticide component naled, in methyl eugenol poison bait for oriental fruit fly (Bactrocera dorsalis), will easily decompose through dichlovos to non-toxic material by sunlight photolysis. Brown bottle packing of poison bait can prevent naled from decomposing by shading off the sunlight, hence stablize the formulation of this bait. Poison bait for control of melon fly (Bactrocera cucurbitae) contains cuelure, methyl eugenol and naled. The photo-decomposition of naled also occurred under sunlight in even faster rate than that of methyl eugenol-naled bait. The increase rate of decomposition may due to the mixing of more components in the bait. Brown bottle packing can also prevent the naled from decomposing. In the melon fly poison bait, 12~20% cuelure was deacetylated in a 2-month period, which was not affected by sunlight or temperature in the condition of this experiment. The loss of cuelure by autolysis should be specified for registering commercial formulation of melon fly poison bait