Establishing discriminating concentrations of indigenous plant-based insecticides against adult Aedes aegypti (L.) and Aedes albopictus Skuse (Diptera: Culicidae)

The increasing prevalence of insecticide resistance in Aedes mosquitoes necessitates development of alternative control methods. This study evaluated adulticidal efficacy of essential oils from Litsea cubeba, Syzygium aromaticum, and Cinnamomum porrectum against laboratory and field populations of Aedes aegypti and Aedes albopictus. Discriminating concentrations (DCs) were established using WHO tube tests. L. cubeba showed the lowest DCs (6.21% v/v for Ae. aegypti, 9.68% v/v for Ae. albopictus), followed by C. porrectum (9.70%, 15.55%) and S. aromaticum (19.40%, 24.33%). At these DCs, all oils demonstrated 98-100% knockdown and 99-100% mortality against field populations. Aedes albopictus required higher DCs than Ae. aegypti, suggesting species-specific susceptibility differences. Essential oils showed superior efficacy against field-collected Ae. aegypti compared to cypermethrin. Results indicate potential of these oils as effective botanical insecticides, particularly where conventional insecticide resistance occurs.