Toxicological studies of organophosphate and pyrethroid insecticides for controlling the fruit fly Dacus ciliatus (Diptera : Tephritidae)

The fruit fly Dacus ciliatus Loew is a pest of the fruits of many cucurbit species. We studied the effect of organophosphate and pyrethroid compounds on the adult flies by using surface contact and oral administration. In con trast to other fruit flies, we found that organophosphates were ineffective against D. ciliatus. This was supported by the insignificant decrease of h ead acetylcholinesterase activity. All tested pyrethroids showed satisfacto ry killing ability, rapid and massive knockdown effect, and prevention of o viposition. Piperonyl butoxide considerably increased the toxicity of pyret hroids, which can be explained by oxidase detoxification of these compounds in D. ciliatus. It can be concluded that pyrethroids have high potential f or controlling D.ciliatus.