22 Ara 2024 Pazar
Comparative lethal effects of three Ocimum plants species against Culex quinquefasciatus mosquito larvae
Abstract :Successes have been reported from studies involving the use of botanical derivatives as larvicides, repellents or insecticides. The toxicity of the aqueous, methanolic and oil extracts of the three plants: Ocimum gratissimum L., O. canum Sims and O. basilicum L. (family: Labiacae) were tested on the 3rd instars larvae of Culex mosquitoes which is an important vector for filariasis, encephalitis to humans. This approach is meant to find a safer and cheaper alternative for vector control. The extracts were graded into concentrations and the larvae were exposed to test for 3 and 24 hours with percentage mortality of 74.17% at LC50 value of 0.95g/ml in methanolic extract of O. basilicum being the most potent after 24 hours followed by O. canum (methanol) with 71.83%, O. basilicum aqueous (68.33%) and O. gratissimum methanol extract (65%). However, the oil extract of O. canum was most potent after 3hours with 57.33% mortality (LC50 = 1.0g/ml), followed by O. basilicum 49.33% (LC50 = 1.0mg/ml) while O. gratissimum was the least toxic at 42.00% mortality (LC50 = 2.0g/ml). Invariably, these plants can be incorporated as botanical larvicides to inhibit the growth of mosquito vectors in order to prevent transmission of the mosquito borne diseases.
Toxicity, extracts, Ocimum gratissimum L., Ocimum canum Sims, Ocimum basilicum L.