Toxicity of Aristolochia bracteata methanol leaf extract against selected medically important vector mosquitoes (Diptera: Culicidae)

Abstract

ObjectiveTo evaluate the larvicidal, ovicidal and repellent activities of methanol extract of Aristolochia bracteata (A. bracteata) against Aedes aegypti (Ae. aegypti), Anopheles stephensi (An. stephensi) and Culex quinquefasciatus (Cx. quinquefasciatus). MethodsLarvicidal efficacy of A. bracteata was tested at various concentrations against the early third instar larvae of Ae. Aegypti, An. Stephensi and Cx. quinquefasciatus. Bioassay test was carried out by WHO 2005; the 24h LC50 values of the A. bracteata leaf extract was determined by probit analysis. For ovicidal activity, slightly modified method of Su and Mulla was performed. Ovicidal activity was determined against selected mosquitoes to various concentrations ranging from 50-300 ppm under laboratory conditions. The hatch rates were assessed 48 h post treatment. The repellent efficacy was determined against selected mosquito species at three concentrations viz., 1.0, 2.0 and 3.0 mg/cm2 under laboratory conditions. ResultsThe LC50 and LC90 values of methanol leaf extract of A. bracteata against early third instar larvae of Ae. Aegypti, An. stephensi and Cx. Quinquefasciatus were 114.89, 120.82, 132.24 and 216.24, 230.31, and 238.22 ppm, respectively. The crude extract of A. bracteata exerted 100% egg mortality (zero hatchability) at 240, 300 and 360 ppm for Ae. Aegypti, An. stephensi and Cx. Quinquefasciatus. Similarly, a higher concentration of 6.0 mg/cm2 provide 100% protection up to 210, 180 and 150 min against Ae. Aegypti, An. stephensi and Cx. Quinquefasciatus. ConclusionsThe present results suggest that the A. bracteata methanol leaf extracts provided an excellent potential for controlling selected medically important vector mosquito.