Mosquito larvicidal properties of Impatiens balsamina(Balsaminaceae)against Anopheles stephensi,Aedes aegypti and Culex quinquefasciatus(Diptera:Culicidae)

Objective:To assess the larvicidal potential of the crude benzene,chloroform,ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi(An.stephensi),Aedes aegypti(Ae.aegypti)and Culex quinquefasciatus(Cx.quinquefasciatus).Methods:Twenty five third instar larvae of An.stephensi,Ae.aegypti and Cx.quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO.The larval mortality was observed after 24 h of treatment.Results:Among extracts tested,the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An.stephensi,Ae.aegypti and Cx.quinquefasciatus with the LC_(50)and LC_(90)values 98.04,119.68,125.06 and 172.93,210.14,220.60 mg/L,respectively.Conclusions:From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An.stephensi,Ae.aegypti and Cx.quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

Mosquito repellent potential of Pithecellobium dulce leaf and seed against malaria vector Anopheles stephensi(Diptera:Culicidae)

Objective:To determine the repellent properties of hexane,benzene,ethyl acetate,chloroform and methanol extract of Pithecellobium dulce(P.dulce)leaf and seed against Anopheles stephensi(An.stephensi).Methods:Repellent activity assay was carried out in a net cage(45 cm×30 cm×25 cm)containing 100 blood starved female mosquitoes of An.stephensi.This assay was carried out in the laboratory conditions according to the WHO 2009 protocol.Plant crude extracts of P.dulce were applied at 1.0,2.5,and 5.0 mg/cm^(2) separately in the exposed fore arm of study subjects.Ethanol was used as the sole control.Results:In 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 concentration of the extract.Among the tested solvents,the leaf and seed methanol extract showed the maximum efficacy.The highest concentration of 5.0 mg/cm^(2) leaf and seed methanol extract of P.dulce provided over 180 min and 150 min protection,respectively.Conclusions:Crude extracts of P.dulce exhibit the potential for controlling malaria vector mosquito An.stephensi.

Adulticidal efficacy of Delonix elata against filariasis vector mosquito,Culex quinquefasciatus(Diptera:Culicidae)

Objective:To evaluate the adulticidal activity and toxicity of different solvent crude extracts of Delonix elata(D.elata)against filariasis vector mosquito Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The adulticidal activities of crude hexane,benzene,ethyl acetate,chloroform and methanol leaf and seed extracts of D.elata were assayed for their toxicity against vector mosquitoCx.quinquefasciatus.Bioassay was carried out by WHO method for determination of adulticidal activity against mosquitoes.The adult mortality was observed after 24 h of exposure.Results:All extracts showed moderate adulticidal effects;however,the highest adult mortality was found in methanol extract of D.elata leaf against the adults of Cx.quinquefasciatus with the LC_(50) and LC_(90) values at 197.28 and 347.45mg/L,respectively.Conclusions:These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes.This study provides first report on the mosquito adulticidal activity of D.elata plant extracts against filariasis vector mosquito,Cx.quinquefasciatus.

Mosquito adulticidal properties of Delonix elata(Family:Fabaceae)against dengue vector,Aedes aegypti(Diptera:Culicidae)

Objective:To determine the adulticidal activity of hexane,benzene,chloroform,ethyl acetate and methanol leaf and seed extracts of Delonix elata(D.elata)against Aedes aegypti(Ae.aegypti).Methods:The bioassay was conducted in an experimental kit consisting of two cylindrical plastic tubes both measuring 125 mm×44 mm following the WHO method;mortality of the mosquitoes was recorded after 24 h.Results:The adulticidal activity of plant leaf and seed extracts showed moderate toxic effect on the adult mosquitoes after 24 h of exposure period.However,the highest adulticidal activity was observed in the leaf methanol extract of D.elata against Ae.aegypti with the LC_(50) and LC_(90) values 162.87 and 309.32 mg/L,respectively.Conclusions:From this result,it can be concluded the crude extract of D.elata was an excellent potential for controlling Ae.aegypti mosquitoes.