Toxicity Effects of Abamectin, Spinosad and Chlorpyrifos on Predatory Bug Orius albidipennis Reuter in Laboratory and Greenhouse Conditions

Orius albidipennis Reuter is an important predator of economic pests in greenhouse. In this studu، investigations were performed on toxicity values of abamectin، spinosad and chlorpyrifos in laboratory (Petri dish) and greenhouse (clip cage) conditions. LC50 and LC90 values were determined to both sexes، male and female، by using SAS software، and comparisons were made according to ratio of LC50 values and 95% confidence limits. For males، toxicity of the insecticides was more than females in laboratory and greenhouse conditions. Toxicity rates were significantly different between the insecticides. Chlorpyrifos had the most toxicity in laboratory (LC50=0. 06 ppm for males and LC50= 0. 05 ppm for females) and greenhouse conditions (LC50=83 ppm for males and LC50= 99. 3 ppm for females) and spinosad had the least one. Laboratory and greenhouse trials showed that toxicities of these insecticides were lower in greenhouse bioassay than in laboratory bioassay but this difference was notable for spinosad. It is concluded that multiple testing methods should be used in evaluating the effects of pesticides on beneficial arthropods.