Mosquito repellent properties of Delonix elata (L.) gamble (Family: Fabaceae) against filariasis vector, Culex quinquefasciatus Say. (Diptera: Culicidae)

ObjectiveTo determine the repellent activity of hexane, ethyl acetate, benzene, chloroform and methanol extract of Delonix elata (D. elata) leaf and seed against Culex quinquefasciatus (Cx. quinquefasciatus).MethodsEvaluation was carried out in a net cage (45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of Cx. quinquefasciatus. Repellent activity was carried out in the laboratory conditions according to the WHO 2009 protocol. Plant crude extracts of D. elata were applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed fore arm of study subjects. Ethanol was used as the sole control.ResultsIn this study, the applied plant crude extracts were observed to protect against mosquito bites. There were no allergic reactions experienced by the study subjects. The repellent activity of the extract was dependent on the strength of the extract. Among the tested solvents, the leaf and seed methanol extract showed the maximum efficacy. The highest concentration of 5.0 mg/cm2 provided over 150 min and 120 min protection, respectively.ConclusionsCrude extracts of D. elata exhibit the potential for controlling Cx. quinquefasciatus, the mosquito vector of filariasis.