Hp-45: Gas chromatography analysis and insecticidal activity of eucalyptus radiata essential oil against culex pipiens larvae

Abstract

Culex pipiens L. (Diptera: Culicidae) constitute a mosquito vector of important diseases such as the West Nile virus. For the control of Cx. pipiens larvae, different types of insecticide groups are widely used but this mosquito developed resistance to many of these insecticides. The present study aimed to evaluate the larvicidal effect of Eucalypltus radiata (E. radiata) essential oil (EO) against mosquito larvae Cx pipiens. The EO was extracted by steam distillation method. Chemical composition of essential oil was analyzed by gas chromatography (GC), and the E. radiata EO toxicity was tested against fourth-instar of Cx pipiens larvae following the procedure of the World Health Organization under laboratory conditions. The EO yield was 1.12%. GC analyses revealed thirty compounds in E. radiata EO, only five of them were identified wich are viridiflorol (5.20%), globulol (0.74%), piperitone (0.37%), and Guaiol (0.27%). The larvicidal assay showed that the E. radiata EO exhibited insecticidal activity against the fourth instar larvae of C. pipiens (LC50 = 95.2 ppm and LC90 = 164.9 ppm at 24 hour exposure). The investigation confirmed the toxicological effects of E. radiata EO against mosquito larvae ; consequently, it could be considered as a potent source for producing natural larvicidal agents and bioinsecticides for pest an insect vector control