Evaluation of leaf extracts of Vitex negundo L. (Family: Verbenaceae) against larvae of Culex tritaeniorhynchus and repellent activity on adult vector mosquitoes

Abstract

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.

Larvicidal and irritant activities of hexane leaf extracts of Citrus sinensis against dengue vector Aedes aegypti L.

“…aegypti, Anopheles stephensi and Culex quinquefasciatus [7] . Petroleum ether extracts of Vitex negundo leaves offered 8 h of bite protection (2 mg/cm 2 ) by different mosquito species in the field [24,25] . A patented extract of the seeds of Vitex agnus castus was shown effective against mosquitoes resulting in more than 6 h protection against Culex quinquefasciatus and Anopheles stephensi, and 3-4 h against Ae.…”

Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae)

“…quinquefasciatus, and their LC 50 values were 2 214.7 and 5 362.6 ppm, respectively [38] . Mullai and Jebanesan [39] [41] reported that the petroleum ether (60-80 曟) extracts of the leaves of V. negundo were evaluated for larvicidal activity against larval stages of Cx. tritaeniorhynchus in the laboratory with LC 50 and LC 90 values of 2.488 3 and 5.188 3 mg/L, respectively.…”

Tagetes erecta Linn. and its mosquitocidal potency against Culex quinquefasciatus

“…There is considerable international interest in developing benign natural products as an alternative to harmful synthetic pesticides to control invertebrate pests of medical and economic importance [2,3] . Botanical phytochemicals with mosquitocidal potential are now recognized as potent alternative insecticides to replace synthetic insecticides in mosquito control programs due to their excellent larvicidal, pupicidal and adulticidal properties [4][5][6][7][8] . Phytochemicals are less environmentally harmful than synthetic agrochemicals.…”