Abstract

Mosquitoes are considered as a major problem in public health. Control measures mainly by chemical insecticides, have led to several environmental and health problems in addition to development of resistance. The bioefficacy of aqueous extract of leaves of Duranta erecta against the yellow fever and dengue vector, Aedes aegypti was evaluated as a step towards developing a safe and eco-friendly agent to combat the problems of mosquitoes and mosquito-borne diseases. Pulverized leaves of D. erecta were macerated in 2 L of distilled water for 24 h, filtered and concentrated. The aqueous extract of D. erecta leaves at different dilutions such as 50, 200, 500, 700, 900 and 1000 mg/L were tested against 525 eggs and 1050 fourth instar larvae of A. aegypti using emersion method. The percentage ovicidal, larvicidal activities, pupal and adult emergence, adult immergence and fecundity inhibition were studied. A concentration dependent increase in ovicidal, larvicidal, inhibition of adult emergence and fecundity were recorded. High ovicidal activity (low egg hatchability) was recorded with LC50 (95% CL) values of 340.085 mg/L (250.85-430.17mg/L). High larvicidal, emergence and fecundity inhibition were recorded with LC50 value of 420.59 mg/L (33.34-520.06 mg/L). Preliminary phytochemical analysis showed the presence of tannins, saponins, alkanoids, flavonoids, glycosides and anthroquinone. The results indicated that these botanicals may play an important role in reducing the use of chemicals for mosquito control. In-depth investigations to elucidate the active ingredients of the extract responsible for mosquitocidal activity in Aedes aegypti should be conducted and small scale field trials are needed for utilization.

Key words: Duranta erecta, aqueous extract, Aedes aegypti, mosquitocidal activity.