Lethal effects of four insecticides on eggs and first instar larvae of Chrysoperla carnea )Stephens( (Neuroptera: Chrysopidae) in laboratory conditions.

The common green lacewing Chrysoperla carnea Stephens is a general biocontrol agent of several insectpests in greenhouses. The lethal effects of four compounds imidacloprid, lufenuron, thiametoxam andthiodicarb on eggs, 1st instar larvae and adults of C. carnea were studied in laboratory conditions (25±2 ºC,60±10% RH and 10-h photo phase). Dipping bioassay tests was used for eggs and residual contact methodfor larvae and adults. Positive relationships were detected between the concentrations of insecticides andmortality 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 thehighest ovicidal activity. Order of the ovicidal activity of other insecticides was as follows: thiametoxam>imidacloprid> lufenuron On larvae, thiametoxam was the most toxic (LC50= 0.55 μg ai. L-1) and lufenuronproved to be the least toxic (LC50 = 44.02 μg ai. L-1). LC50 value of lufenuron, imidacloprid and thiodicarbwere about 80, 25 and 29 times higher than that of thiametoxam, respectively So thiametoxam are notrecommended to be used in IPM programs as for recommendation of Lufenuron and thiodicarb, they needs tobe more studied.

کلیدواژه ها:

Chrysoperla carnea ، imidacloprid ، lufenuron ، thiametoxam ، thiodicarb