Larvicidal, ovicidal and repellent activities of the leaf extract of two cucurbitacious plants against filarial vector Culex quinquefasciatus (Say) (Diptera : Culicidae).

The leaf extract of two cucurbitacious plants Citrullus colocynthis and Cucurbita maxima with different solvents viz., benzene, ethylacetate, petroleum ether and methanol were tested for larvicidal, ovicidal and repellent activities against the mosquito Culex quinquefasciatus. Larval mortality was observed and recorded after 24 h exposure period. The LC50 values of C. colocynthis were 61.72, 47.58, 66.92 and 118.74 ppm respectively. C. maxima shows the LC50 values of 123.02, 75.91, 117.73 and 171.64 ppm respectively. The mean percent hatchability of the egg rafts were observed after 48 h treatment. 100% mortality was observed at 450 ppm for C. colocynthis and 600 ppm for C. maxima. Skin repellent test at 1.0, 2.5 and 5.0 mg/cm2 concentration of C. colocynthis gives the complete protection time ranges from 107 to 271 minutes. C. maxima exerted the complete protection time of 78 to 215 minutes. The leaf extract of these two plants shows the larvicidal and ovicidal properties and they can also be applied as an effective personal protection measure against mosquito bites.