The common green lacewing Chrysoperla carnea (Stephens) is a general biocontrol agent of several insect pests in greenhouses. The lethal effects of four compounds imidacloprid, lufenuron, thiametoxam and thiodicarb on eggs and 1st instar larvae of C. carnea were studied in laboratory conditions. Dipping bioassay tests were used for eggs and residual contact method for larvae. Positive relationships were detected between the concentrations of insecticides and mortality rates of various stages. However, there were considerable variations in toxicity of insecticides. Thiodicarb had no effect on eggs, whereas thiametoxam with the LC50 value of 1.90 μg ai. L-1 showed the highest ovicidal activity. On larvae, thiametoxam was the most toxic (LC50= 0.55 μg ai. L-1) and lufenuron proved to be the least toxic (LC50 = 44.02 μg ai. L-1). The use of thiametoxam should be carefully evaluated if employed in combination with C. carnea in IPM programs.

Keywords