Mosquitocidal and repellent activity of the leaf extract of Citrullus vulgaris (cucurbitaceae) against the malarial vector, Anopheles stephensi liston (diptera culicidae)

The efficacy of the Cucurbitaceous plant Citrullus vulgaris against the Anopheles stephensi was assessed in the present study. The leaf extract of Citrullus vulgaris with different solvents viz, benzene, petroleum ether, ethyl acetate and methanol were tested for larvicidial, ovicidal, repellent and insect growth regulatory activities against Anopheles stephensi. The larval mortality was observed after 24 h exposure. The LC50 values are 18.56, 48.51, 49.57 and 50.32 ppm respectively. The mean percent hatchability of the egg of Anopheles stephensi were observed after 48 h. 100 per cent mortality was exerted at 250 ppm with benzene extract and the other extracts exerted 100 percent mortality at 300 ppm. Skin repellent test at 1.0, 2.5 and 5.0 mg per cm(2) concentration gave the mean complete protection time ranged from 119.17 to 387.83 minutes with the four different extracts tested. The Citrullus vulgaris plant extract have shown insect growth regulatory activity against Anopheles stephensi at five different test concentrations ranging from 10 to 150 ppm with different solvents and they exhibit the following EI50 values 28.99, 70.02, 106.33 and 84.25 ppm respectively.