Repellent activities of ethanolic extract of Cymbopogon citratus (Poaceae) and Ocimum basilicum L. (Lamiaceae) leaves against Culex quinquefasciatus mosquitoes (Diptera: Culicidae) in Dogbo district in south-western Benin, West Africa

The alteration of mosquito life cycle using larvicides is key in the control of diseases transmitted by mosquitoes. The residual and environmental effect of some of these synthetic larvicides has given an opportunity to search for a potent larvicide as an alternate control measure against mosquitoes. The current study was aimed to evaluate the repellent activities of ethanolic extract of Cymbopogon citratus (Poaceae) and Ocimum basilicum L. (Lamiaceae) leaves against Culex quinquefasciatus adult mosquitoes in lymphatic filariasis vector control in Dogbo district in south-western Republic of Benin. Larvae of Culex quinquefasciatus mosquitoes were collected from breeding sites using the dipping method from September to November 2023 during the small rainy season in Dogbo district of Couffo department. Then, these larvae were reared in insectary until became adult mosquitoes. Repellent activities of ethanolic extract of both plant leaves were measured on adult mosquitoes with different concentrations of 1mg/cm2, 2mg/cm2, 3mg/cm2, 4mg/cm2 and 5mg/cm2. The results showed that the leaves of both plant had repellent effects against Culex quinquefasciatus adult mosquitoes. However, the repellent effect of Cymbopogon citratus leaves was higher than that of Ocimum basilicum L. leaves. Both ethanolic extracts of Cymbopogon citratus and Ocimum basilicum L leaves are found to be effective in the repellency against the bites of Culex quinquefasciatus adult mosquitoes.