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 organaophosphate and pyrethroid compounds on the adult flies by using surface contact and oral administration. In contrast to other fruit flies, we found that organophosphates were ineffective against D. ciliatus. This was supported by the insignificant decrease of head acetylcholinesterase activity. All tested pyrethroids showed satisfactory killing ability, rapid and massive knockdown effect, and prevention of oviposition. Piperonyl butoxide considerably increased the toxicity of pyrethroids, which can be explained by oxidase detoxification of these compounds in D. ciliatus. It can be concluded that pyrethroids have high potential for controlling D. ciliatus.