Toxicity and side effects of three insecticides on adult Chrysoperla carnea (Neu.: Chrysopidae) under laboratory conditions

Green lacewing, Chrysoperla carnea (Stephens), is an important predator of arthropod pests such as aphids, psyllids, thrips and whiteflies. Toxicity of endosulfan, imidacloprid and indoxacarb was assessed on male and female C. carnea in the laboratory. Contact bioassays were carried out in glass Petri dishes. The LC50 values for indoxacarb, imidacloprid and endosulfan were 0.011, 0.053, and 0.343 g AI/L for males, and 0.019, 0.098 and 0.398 g AI/L for females, respectively. Males were more sensitive than females to all three insecticides. To assess the sublethal effects, using IOBC (International Organization for Biological Control) method, adults were treated with LC25 of each insecticide. Analysis of variance did not show significant differences among treatments regarding the developmental time of the first, second and third instars, pupae and sex ratio. Differences between treatments and control were significant regarding pre-oviposition, oviposition and post-oviposition periods, fecundity, fertility, longevity of male and female. Mean longevity for control, imidacloprid, endosulfan and indoxacarb were 30 ± 2.3, 24.3 ± 3.3, 21.3 ± 2.4 and 19.7 ± 1.4 days for males, and 36.9 ± 2.5, 31.8 ± 2.9, 27.7 ± 1.7 and 26.7 ± 2.6 days for females, respectively. The highest and the lowest rates of fecundity were 540 ± 49 and 206 ± 42 in control and indoxacarb, respectively. Based on the IOBC classification method, imidacloprid, endosulfan and indoxacarb were slightly harmful (%30 < Total Effect Index < %79) against adults. The adult stage was very sensitive to indoxacarb, imidacloprid and endosulfan. Hence, these insecticides should not be applied when the density of adults is high in the field.