The effect of Methanolic extracts of Solenostemma argel (Argel), Rhazya stricta (Harmal), Heliotropium bacciferum (Ramram), and Thymus vulgaris (Zaatar) ; and aqueous extracts of: Calotropis procera (Ushar), Rhazya stricta, Francoeuria crispa (Githgath), Trigonella foenum-graecum (Hilba), Azadirachta indica seeds (neem seeds), and Artemisia abyssinica (Shih) were investigated against Culex pipiens oviposition, egg hatchability, and toxicity to larvae.
Oviposition was suppressed in concentrations as low as 0.05% aqu. extract of R. stricta, C. procera and F. crispa; and 0.025% methanolic extract of S. argel. C. procera and A. indica (0.1% aqu. extract) reduced egg hatch by 52 and 43% , and R. stricta (0.05 and 0.1% meth. extract) it was reduced by up to 54%.
Acute larval toxicities (2 DAT) were 270 and 322 ppm for R. stricta and C. procera, respectively. Larvae suffered mortalities in extracts of C. procera (0.025% aqu. extr), T. vulgaris (0.5 and 1.0% meth. extr.) and A. indica (0.1% aqu. extr.) up to 100, 97.5, 90.2 and 42.2%, resp. Acute toxicity in the 0.2 and 0.4% methanolic extract of S. argel amounting to 100% 48-hr mortality. A concentration as low as 0.025% of S. argel produced 84%, 97.4%, and 100% mortality on 4th , 7th , and 10th DAT, respectively.
Species 1: Diptera Culicidae Culex pipiens (mosquitoes)
Keywords: medicinal plants, methanolic and aqueous extracts
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