TOTAL PHENOLIC AND FLAVONOID CONTENT IN THE ESSENTIAL OILS OF SELECTED PLANTS AND ITS INSECTICIDE ACTIVITY FOR SUSTAINABLE CONTROL OF RED PALM WEEVIL (Rhynchophorus ferrugineus)

Essential oils offer a promising alternative to chemical pesticides, which pose environmental and health risks. However, comprehensive field studies evaluating their long-term effectiveness and practical application in diverse agricultural settings are lacking. This study investigates the insecticidal efficacy of essential oils from four plants: Cymbopogon citratus (lemongrass), Melaleuca cajuputi (gelam), Vitex rotundifolia (beach vitex), and Pandanus amaryllifolius (pandan) to control the red palm weevil (Rhynchophorus ferrugineus, RPW). The oils were assessed for their antifeedant and repellent properties to contribute to sustainable pest management strategies. Gelam oil had the highest levels of phenolics and flavonoids while pandan oil had the lowest. Prickmark analysis revealed that lemongrass oil had the greatest deterrent effect against RPW feeding, followed by gelam and beach vitex, with pandan oil showing no antifeedant activity. A Y-tube olfactometer evaluated the repellent effectiveness of the oils. Lemongrass and beach vitex had slightly attractive characteristics while gelam and pandan oils effectively repelled RPWs. Male and female RPWs responded differently: Males were more attracted to lemongrass and beach vitex while females were more repulsed by gelam and pandan. These findings suggest that essential oils’ insecticidal properties could help develop gender-specific and sustainable agricultural pest management plans.