Larvicidal and Pupicidal Toxicities of <i>Plectranthus glandulosus</i> and <i>Callistemon rigidus</i> Leaf Essential Oils against Three Mosquito Species

Abstract

Objective: To determine the mosquito larvicidal and pupicidal potencies of Cameroonian Plectranthus glandulosus and Callistemon rigidus leaf essential oils against 4 th instar larvae and early pupae of Anopheles gambiae , Aedes aegypti and Culex quinquefasciatus . Methods: Twenty five early 4 th instar larvae and early pupae of An. gambiae , Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations ranging from 12.5-500 ppm and 2000 ppm for DDVP. The standard protocol of WHO 2005 was followed up under laboratory conditions. The larval and pupal mortalities were observed 24 h post-exposure. Probit analysis was used to determine the LC 50 and LC 90 Results: The essential oil of the two plants showed significant larvicidal and pupicidal potential against all the target mosquito species. P. glandulosus caused LC 50 values of 2.66, 7.37 and 43.16 ppm against Ae. aegypti , An. gambiae and Cx. quinquefasciatus larvae, respectively and 27.22, 22.60 and 104.75 ppm against Ae. aegypti , An. gambiae and Cx. quinquefasciatus pupae, respectively. C. rigidus displayed LC 50 values of 66.67, 99.61 and 176.81 ppm against Ae. aegypti , An. gambiae and Cx. quinquefasciatus larvae, respectively and 50.95, 47.63 and 307.19 ppm against Ae. aegypti , An. gambiae and Cx. quinquefasciatus pupae, respectively Conclusion: These results suggest that the Cameroonian P. glandulosus and C. rigidus leaf essential oils can be used as an ideal ecofriendly approach that may replace DDVP, the synthetic chemical, for vector control programs.