Effect of soil application of imidacloprid on survival of adult green lacewing, Chrysoperla carnea (Neuroptera: Chrysopidae), used for biological control in greenhouse

In the greenhouse, survival of adult green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), was reduced after feeding on flowers from plants treated with a soil application of imidacloprid (Marathon 1% G, label rate and twice label rate). Percent survival for C. carnea at 10 d was statistically different between treatments and controls: 79% for untreated flowers, 14% for label rate, and 6% for twice label rate. Trembling was observed in imidacloprid treatments, but not controls. A cold anthrone test showed that C. carnea were feeding equally from all treatments, confirming that lacewings were not starving to avoid feeding on treated flowers. In support of these data, a previous study in this system using residue analysis demonstrated that soil-applied imidacloprid was translocated to flower nectar. Consequently, plants treated with imidacloprid for the control of greenhouse pests will reduce populations of C. carnea and lower their efficacy as biological control agents.