Differential larvicidal efficacy of four species of <Emphasis Type="Italic">Vitex</Emphasis> against <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> larvae

The early fourth instar larvae of Culex quinquefasciatus, reared in the laboratory were used for larvicidal assay with leaf extracts of Vitex negundo, Vitex trifolia, Vitex peduncularis and Vitex altissima. The methanol extracts of the four species possessed varying levels of larvicidal nature. The highest larvicidal activity was found with the extract of V. trifolia (LC₅₀ = 41.41 ppm) followed by V. peduncularis (LC₅₀ = 76.28 ppm), V. altissima (LC₅₀ = 128.04 ppm) and V. negundo (LC₅₀ = 212.57 ppm).