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Evaluation of larvicidal activity of the leaf extract of a weed plant, Ageratina adenophora , against two important species of mosquitoes, Aedes aegypti and Culex quinquefasciatus

African Journal of Biotechnology (ISSN: 1684-5315) Vol 6 Num 5
Source: OAI

ABSTRACT An attempt is made in the present study to analyse the larvicidal effect of the leaf extract of a vastly grown (in the hilly regions of the Nilgiris district) weed plant, Ageratina adenophora on two important mosquito species, Aedes aegypti and Culex quinquefasciatus. The larval mortality of fourth instar larvae of A. aegypti and C. quinquefasciatus after 24 h of treatment were observed separately in control, 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500 ppm concentrations of the leaf extract (acetone) of κA. adenophora. Based on the Probit analysis, the 24 h Lc50 value of the leaf extract of A. adenophora was found to be 356.70 ppm for A. aegypti and 227.20 ppm for C. quinquefasciatus. When compared to neem, the leaf extract of A. adenophora is more toxic to both A. aegypti and C. quin-quefasciatus and could be effectively used for the control of mosquito larvae.

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    ABSTRACT: Culex quinquefasciatus Say, an arboviral and filarial vector, is one of the most widespread mosquitoes in the world, and insecticide-resistant populations have been reported worldwide. Due to the emergence of resistance in C. quinquefasciatus plant based products or plant extracts may be alternative sources in integrated vector management program. The present study was carried out to establish the larvicidal activities of crude solvent extracts prepared from flowers and leaves of Ipomoea cairica and Ageratina adenophora against third instar larvae of C. quinquefasciatus as target species. The plant extracts were prepared with petroleum ether, choloroform and methanol solvents using sequential extraction method to determine the best extractant for subsequent isolation and characterization of active ingredient. The total yield of plant extract in the soxhlet extraction ranged between 0.79% and 19.35%. The qualitative phytochemical study of the plant extracts from different solvents showed the presence of alkaloids, flavonoids, phenols, terpenes, saponins and tannins in different combinations. I. cairica and A. adenophora plant extracts were found to be effective against third instar larvae of C. quinquefasciatus causing 77 - 100% mortality at 48 h. Highest mortality was observed at 500 ppm and the order of larvicidal action was observed to be of methanol extract of I. cairica flower > petroleum ether extract of A. adenophora leaf >chloroform extract of I. cairica leaf. High mortality (100%) with low LC50 and LT50 were observed in methanolic flower extract (LC50 - 8.43 ppm; LT50- 2.51 h at 48 h) of I. cairica, and petroleum ether (LC50 - 133.56 ppm; LT50 - 9.45 h at 48 h) leaf extract of A. adenophora. Lethal concentration (LC50 and LC90) values gradually decreased with the exposure periods, lethal time (LT50 and LT90) decreased with the concentration in bioassay experiment with the crude plant extracts. There was a significant correlation (three-way factorial ANOVA) was noticed among concentration of the plant extracts, exposure time and solvent extraction in relation to larval mortality (P < 0.0001), which indicates that larval mortality is concentration dependent as well as time-dependent. Further in-depth study is needed to identify and characterize the active components present in the plant solvent extracts and implement the effective arboviral and filarial mosquito vector management program.
    Experimental Parasitology 06/2014; DOI:10.1016/j.exppara.2014.03.020 · 1.86 Impact Factor
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    ABSTRACT: Objective: To determine the phytochemical analysis and larvicidal activity of Trgia involucrata leaf extracts against fourth instar larvae of Aedes aegypti. Methods: Phytochemical analysis of hexane leaf extract and larvicidal activity was determined against two vector mosquito species at concentrations of 50, 100, 150, 200 and 250 ppm. Larval mortality was assessed after 24 hours. Results: The hexane extracts of Trgia involucrata was found to be higher mortality against the larvae of Aedes aegypti with a LC50 value of 153.51 ppm. Conclusions: These results suggested that the leaf extracts of Trgia involucrata showed potential to be used as an ideal ecofriendly approach for the control of the Aedes aegypti.
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    ABSTRACT: Larvicidal activity of crude petroleum ether (PE), ethyl acetate (EtOAc) and methanol (MeOH) extracts of leaves and stem barks of Sterculiaquinqueloba (Garcke) K. Schum were testedagainst the late 3rd instar larvae of Anopheles gambiae, Aedesaegypti and Culexquinquefasciatusat 5 different concentrations50 – 800μg/ml. The larval mortality was observed after 24h, 48h and 72h of exposure. At 24h of exposure all extracts showed moderate larvicidal effects, except for methanolic extracts which showed very week effect at LC50>750μg/ml.The highest larvicidal activityrecorded for leaf extracts against each species used were LC5027.61μg/ml(EtOAc extracts), LC50 43.9μg/ml(PE extracts) and LC50 68.2μg/ml(EtOAc extracts) for A. gambiae, C. quinquefasciatus and A. aegypti respectively. Only EtOAc extract of stem against A. gambiae gave LC50range between 50 - 100μg/ml. Generally leaf extracts showed higher activity than stem extract. This is an ideal eco-friendly approach aid for the control of mosquito species A. gambiae, A. aegypti and C. quinquefasciatus.

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