Evaluation of leaf extracts of Vitex negundo L. (Family: Verbenaceae) against larvae of Culex tritaeniorhynchus and repellent activity on adult vector mosquitoes.
Petroleum ether (60-80 degrees 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.
Karunamoorthi
Kaliyaperumal
K
Unit of Vector Biology and Control, School of Environmental Health Science, Faculty of Public Health, Jimma University, Jimma, Ethiopia. k_karunamoorthi@yahoo.com
Ramanujam
Sayeenathan
S
Rathinasamy
Rajendran
R
D000818:Animals; D003465:Culex / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D007302:Insect Repellents / Q000302:isolation & purification / Q000494:pharmacology*; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology; D007814:Larva / Q000187:drug effects*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D016019:Survival Analysis; D020950:Vitex / Q000737:chemistry*
D007302:Insect Repellents; D007306:Insecticides; D010936:Plant Extracts