Abstract
Petroleum ether (60–80°C) extracts of the leaves of
Vitex negundo
(Verbenaceae) were evaluated for larvicidal activity against larval stages of
Culex tritaeniorhynchus
in the laboratory. Larvae of
C
.
tritaeniorhynchus
were found more susceptible, with LC
50
and LC
90
values of 2.4883 and 5.1883 mg/l, respectively. Human volunteers wearing special terricot (68:32) fabrics, in the form of armbands, anklets, headbands, collar, and shoulder and pocket strips impregnated with
V
.
negundo
leaf extract were used, to test their repellent efficacy at two concentrations viz., 1.5 and 2.0 mg/cm
2
under the field conditions. At 1.5-mg/cm
2
concentration, more efficacies were found and 6-h complete protection against mosquito bites was provided. Complete protections for 8 h were found at 2.0 mg/cm
2
against mosquitoes bites. These results clearly reveal that the
V
.
negundo
leaf extract served as a potential larvicidal agent against Japanese encephalitis vector
C
.
tritaeniorhynchus
and additionally acted as a promising repellent against various adult vector mosquitoes.