Activity of Otostegia fruticosa (Lamiaceae) Leaves Extracts Against Lymphatic Filariasis Vector, Culex pipiens L. (Diptera: Culicidae)

Document Type : Original Article


Department of Zoology and Entomology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, 11651, Egypt.


The present study was carried out to evaluate the activity of methanol, ethyl acetate, chlorobenzene, and hexane extract from leaves of Otostegia fruticosaas larvicidal and repellent agents against Culex pipiens. The effect of tested extracts on the female reproductive potential treated as larvae was also investigated. The obtained results showed that hexane extract have potent larvicidal activitywithLC50 and LC90 values equal to (126.27 and 236.84 ppm), respectively followed by chlorobenzene (242.14 and 501.17 ppm), ethyl acetate (578.07 and 856.29 ppm) and methanol (653.00 and 1127.10 ppm). All tested extracts of O. fruticosa induced significant (P<0.01) reduction in fecundity and increased the infertility percentages of C. pipiens females developed from treated larvae as compared with control and these effects were solvent- and concentration-dependent. In addition, the repellency effect of tested extracts was found to be varied among tested extracts. Four hours post-treatment, the dose of 3.33 mg/cm2 recorded repellency percentages of 64.13 and 75.09 by methanol and ethyl acetate extracts, respectively. Meanwhile, chlorobenzene extract induced repellency percentages of 80.15, 75.94, and 65.84 for the doses of 3.33, 1.67 and 0.83 mg/cm2, respectively. Moreover, repellent activity of hexane extract at doses of 3.33, 1.67 and 0.83 mg/cm2 recorded 88.08, 79.01 and 75.50%, respectively.