Larvicidal activity and component interactions of Leonotis nepetifolia essential oil against Aedes aegypti.

This study evaluates the larvicidal activity of Leonotis nepetifolia essential oil and its major sesquiterpenes against Aedes aegypti larvae, with a focus on interaction effects among components. The essential oil exhibited strong larvicidal activity. While individual constituents and binary mixtures showed variable effects ranging from slight synergism to antagonism, ternary combinations consistently produced pronounced synergistic interactions. These findings demonstrate that larvicidal efficacy is strongly dependent on mixture composition and cannot be reliably predicted from single components or simple pairwise combinations. Importantly, the results highlight the potential of optimizing defined sesquiterpene mixtures to develop more effective plant-based larvicidal formulations.