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