Larvicidal and ovicidal properties of some plants from asteraceae family against zika virus, dengue and chikungunya vector, Aedes aegypti Linn. (diptera: culicidae)
This study was carried out to evaluate the larvicidal and ovicidal activities of leaves extract from Aspilia africana (Pers.) C. D. Adams, Tithonia diversifolia (Hemsl.) A. Gray, Vernonia amygdalina Del., Tridax procumbens Linn.,Vernonia cinerea (Linn.) Less, Struchium sparganophora (Linn.) Kuntze, Ageratum conyzoides Linn., Melanthera scandens (Schum et Thonn.) Roberty, Chromolaena odorata (Linn.) Hassk, Emilia coccinea (Sims) G.Don, Synedrella nodiflora (L.) Gaertn, Launaea taraxacifolia (Willd.) Amin ex C, Jeffrey, Senecio biafrae Oliv. & Hiern, Crassocephalum crepidioides (Benth.) S.Moore, Eclipta alba (Linn.) Hassk, Spilanthes filicaulis (Schumach. & Thonn.) C.D.Adams, Acanthospermum hispidum D.C. and Bidens pilosa Linn. all inAsteraceae family. The extracts were all tested against Aedes aegypti Linn. eggs and larvae. Twenty each were counted into each of the various concentrations of the eighteen aqueous plant extracts: 62.5, 125, 250, 500, and 1000 mg/L.They were each put in a labeled transparent bowl (300ml). The hatch rates were assessed at 48 hours post-treatment while the percentage mortality of 2nd instar larvae was determined 24 hours post treatment. Spilanthes filicaulis exerted 100% mortality at 1000, 500 and 250 mg/L while Bidens pilosa and Acanthospermum hispidum exerted 100% mortality at 1000 and 500mg/L. Zero percent hatchability was recorded for Spilanthes filicaulis, Bidens pilosa and Acanthospermum hispidum at 1000 and 500 mg/L.The order of increasing larvicidal activity (percent mortality) is Spilanthes filicaulis (100.00 ± 0.0) >Bidens pilosa (71.25 ± 1.3) >Acanthospermum hispidum (58.75 ± 2.4) at 1000mg/L. Other plant extracts showed little or no mortality. Our findings suggest that the aqueous leaf extracts of Spilanthes filicaulis, Bidens pilosa and Acanthospermum hispidum were very effective against eggs and larvae of this important vector specie. The leaf extract of these plants therefore could be a potential source of herbal larvicide for vector control and could be used in integrated vector management which is being encouraged by WHO.
Keywords: Leaf; Aqueous Extracts; Nigerian Asteraceae Plants; Larvicidal Activities; Ovicidal Activities; Aedes aegypti; Plant Larvicides