Adulticidal, larvicidal, pupicidal and oviposition deterrent activities of essential oil from Zanthoxylum limonella Alston(Rutaceae) against Aedes aegypti(L.) and Culex quinquefasciatus(Say)

Objective: To evaluate adulticidal, larvicidal and oviposition deterrent response of the essential oil from dried Zanthoxylum limonella(Z. limonella) fruit against Aedes aegypti(Ae. aegypti) and Culex quinquefasciatus(Cx. quinquefasciatus).Methods: Z. limonella oil was tested by biological assays at 1%, 5% and 10% concentrations in ethanol. Adulticidal efficacy was tested against the 2–3 day old adult females. Larvicidal activity was tested against immature stage of mosquitoes. Oviposition deterrence of the oil was evaluated on gravid females.Results: The adult mortality was observed after 24 h with the LC50 of 6.0% for Ae.aegypti, and 5.7% for Cx. quinquefasciatus. Larvicidal bioassay was carried out with the 10% Z. limonella oil against immature stages of Ae. aegypti and Cx. quinquefasciatus,which caused 100% mortality after 12 h and 24 h. In the larvicidal experiment,Z. limonella showed effective result at 1%, 5% and 10% concentrations with the values of LT50 Ae. aegypti = 9.78, 5.61, 0.24 h for larvae and LT50= 64.08, 21.23 h for pupae;Cx. quinquefasciatus had LT50= 28.46, 20.25, 1.01 h for larvae and LT50= 67.52, 27.96,4.11 h for pupae, respectively. Oviposition deterrence of the oil was evaluated on gravid females. In the study, 10% Z. limonella showed 100% repellency for Ae. aegypti and99.53% for Cx. quinquefasciatus. Likewise, oviposition activity indexes of these oil concentrations were all negative values ranging from–0.89 to-1.00 for Ae. aegypti and–0.64 to–0.99 for Cx. quinquefasciatus. The oviposition activity indexes values revealed that Z. limonella oil has deterrent effect, and it caused a remarkable negative response resulting in very few eggs.Conclusions: This result indicates that Z. limonella oil can be used as an effective adulticide, larvicide and oviposition deterrent against Ae. aegypti and Cx. quinquefasciatus.

Efficacies of four plant essential oils as larvicide, pupicide and oviposition deterrent agents against dengue fever mosquito, Aedes aegypti Linn.(Diptera: Culicidae)

Objective:To evaluate larvicidal,pupicidal and oviposition deterrent activities of four plant essential oils from Alpinia galanga(L.)Willd rhizome,Anethum graveolens L.(An.graveolens)fruit,Foeniculum vulgare Mill.fruit,and Pimpinella anisum L.fruit against Aedes aegypti(Ae.aegypti).Methods:Four essential oils at 1%,5%and 10%concentrations were assessed for insecticidal activity against larvae and pupae of Ae.aegypti,following the procedure of a dipping method assay.Oviposition deterrent activity of four essential oils was evaluated on gravid female of Ae.aegypti by a dual-choice oviposition bioassay.Results:The results revealed that An.graveolens oil provided the strongest larvicidal activity against Ae.aegypti among four tested plant essential oils with the highest mortality rate of 100%and LC_(50)value of-0.3%.From the pupicidal experiment,An.graveolens also showed the highest toxicity against Ae.aegypti pupae with the highest mortality rate of 100%at 72 h and LC_(50)value of2.9%.In addition,10%An.graveolens had an oviposition deterrent effect against Ae.aegypti with effective repellency of 100%and an oviposition activity index of-1.0.Conclusions:An.graveolens oil has a good potential as a larvicidal,pupicidal and oviposition deterrent agent for controlling Ae.aegypti.

Pesticidal activity of Rivina humilis L.(Phytolaccaceae)against important agricultural polyphagous field pest,Spodoptera litura(Fab.)(Lepidoptera:Noctuidae)

Objective:To evaluate the pesticidal activity of antifeedant,oviposition deterrent,ovicidal and larvicidal activities of benzene,dichloromethane,diethylether,ethylacetate and methanol extracts of Rivina humilis at different concentrations against agricultural polyphagous pest Spodoptera litura(Lepidoptera:Noctuidae)(S.litura).Methods:Antifeedant activities of the selected plant extract were studied as described by Isman et al.(1990),with slight modifications.For oviposition deterrent activity,ten pairs of(adult moths)S.litura were subjected in five replicates.After 48 h,the numbers of eggs masses laid on treated and control leaves were recorded and the percentage of oviposition deterrence was calculated.The ovicidal activity was determined against the eggs of S.litura.Twenty five early fourth instar larvae of S.litura were exposed to various concentrations and was assayed by using the protocol of Abbott’s formula(1925);the 24 h LC_(50)values of the Rivina humilis leaf extract was determined by probit analysis.Results:All the extracts showed moderate antifeedant activitiy;however,significant antifeedant,ovicidal,oviposition deterrent and larvicidal activities were observed in methanol extract.Conclusions:This study showed that the selected plant can be a potent source of natural antifeedant,oviposition deterrent,ovicidal and larvicidal activities against field pest S.litura.

Bioefficacy of Caesalpinia bonducella extracts against tobacco cutworm,Helicoverpa armigera(Hub.)(Lepidoptera:Noctuidae)

Objective:To evaluate the antifeedant,oviposition deterrent,ovicidal and larvicidal activities of benzene,dichloromethane,diethylether,ethyl acetate and methanol extracts of Indian medicinal plant,Caesalpinia bonducella(C.bonducella)at different concentrations against Lepidopteran agricultural field pest Helicoverpa armigera(Lepidoptera:Noctuidae).Methods:Antifeedant activities of the selected plant extract were studied using leaf disc no-choice method and oviposition deterrent,ovicidal and larvicidal activities were also assessed by adapting the standard protocols.Results:The antifeedant activity of C.bonducella showed significant antifeedant activity in methanol extract.Oviposition deterrency is higher in methanol extract than the other solvent extracts.Similarly,maximum egg mortality was observed in methanol leaf extract of C.bonducella Lethal concentration,LC_(50)value of benzene,diethylether,dichloromethane,ethyl acetate and methanol extract of C.bonducella were 470.02,469.00,465.47,460.52 and 443.87 mg/L respectively.The Chi-square values are significant at P<0.05 level.Among five solventextracts,the methanol extract was responsible for strong lethal activity observed against selected pest species.Conclusions:Results of this study show that the selected Indian medicinal plant C.bonducella could be a potent source of natural antifeedant,oviposition deterrent,ovicidal and larvicidal agent against the field pest Helicoverpa armigera.