Larvicidal activity of Hibiscus abelmoschus Linn. (Malvaceae) against mosquitoes.

The larvicidal activity of roots of Hibiscus abelmoschus was evaluated against the larvae of mosquitoes in the genera Anopheles and Culex. Mean median lethal concentration values of the aqueous extract from the roots of H. abelmoschus against the larvae of Anopheles culicifacies, An. stephensi, and Culex quinquefasciatus were 52.3, 52.6, and 43.8 ppm, respectively. Efficacy of fraction code HAM-4 decreased with an increase in water depth when sprayed at a dose calculated by surface area. Fraction code HAM-4 at the rate of 82 ppm showed 91.1% reduction of larval An. stephensi in a tank, whereas 87.4% reduction of larval Cx. quinquefaisciatus occurred in a blocked drain 24 h after application of HAM-4 under field conditions.