Essential Oil Composition and Larvicidal Evaluation of Platycladus orientalis against Two Mosquito Vectors, Anopheles stephensi and Culex pipiens

Background: Natural plant products as larvicides could be considered as desirable alternatives to synthetic chemi-cal insecticides for vector management. This study was undertaken to assess the mosquito larvicide activity of the essential oil from fresh leaves of Platycladus orientalis against two medically important species of mosquito vec-tors. Methods: Essential oil was extracted by hydrodistillation and analyzed with gas chromatography and mass spec-trometry (GC-MS). Fresh leaves of P. orientalis tree (500g) were collected in June 2014 from Tehran, Iran and was authenticated at the Department of Medical Entomology and Vector Control, School of Public Health, Tehran Uni-versity of Medical Sciences, Tehran, Iran. In addition, the larvicidal potential of oil was evaluated against late-3rd or young-4th instar larvae of Anopheles stephensi and Culex pipiens under laboratory condition. The mortality counts were made after 24h and LC50 and LC90 values were calculated. Results: Forty-six components in leaves of P. orientalis were identified. The major components were α-Pinene (20.17%), 3-Carene (14%) and Cedrol (9.51%). The LC50 values against An. stephensi and Cx. pipiens larvae were 11.67ppm and 18.60ppm after 24h, respectively. Conclusion: Platycladus orientalis oil could be considered as a natural larvicide for mosquito larval control.