Comparison of larvicidal activities of ethanolic extract of Cymbopogon citratus (Poaceae) and Ocimum basilicum L. (Lamiaceae) leaves in malaria vector control 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 aimed to compare the larvicidal activities of ethanolic extract of Cymbopogon citratus and Ocimum basilicum L. leaves in malaria vector control in Dogbo district in south-western Benin, West Africa. Larvae of Anopheles gambiae sensu lato 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. A batch of twenty-five (25) larvae of four instars were exposed to ethanolic extracts of Cymbopogon citratus and Ocimum basilicum L. leaves with different concentrations of 1 mg/liter, 2mg/liter, 3 mg/liter, 4 mg/liter and 5 mg/liter in some glass jars or plastic test cups of same dimensions covered with small cutting untreated net and in some control, jars containing no trace of these ethanolic extracts. Larval mortality was recorded after 24 hours, 48 hours and 72hours exposure. The results showed that the ethanolic extract of Cymbopogon citratus leaves had the highest larvicidal activity. It was the most effective against larvae of Anopheles gambiae sensu lato. Cymbopogon citratus was found to be effective against the larvae of Anopheles gambiae sensu lato in laboratory conditions. More effort must be done in order to explore the potentiality of these plant parts available for botanical insecticide preparing.