RESUMO
Ethanolic extracts from the Ginkgo biloba L. exocarp from the Chinese ginkgo were assayed against larvae of three strains of Culex pipiens pallens Coquillett. The chemical compositions were detected using a Hewlett-Packard 6890/5973 mass spectrometric detector. The larvicidal bioassay was carried out according to the recommendations of the World Health Organization. The analysis of the essential oil of ginkgo exocarp showed that its major components are ginkgo acid (85.3%) and ginkgo phenolic (5.69%). The larvicidal bioassay showed that extracts of ginkgo exocarp have LC50 of 18.6, 12.7, and 25.0 mg/liter for deltamethrin-susceptible, deltamethrin-resistant, and field strains, respectively. The acute toxicity concentrations of the ginkgo extracts that killed 50% (LD50) of Wistar rats within 2 wk and young carp within 96 h were 4947.2 mg/kg and 557.9 mg/liter, respectively. These results are promising in creating new, effective, and affordable approaches to mosquito control.
