Insecticidal, Antifeedant and Repellent Effects of Five Essential Oils against Fall Armyworm, Spodoptera frugiperda (J. E.Smith)

The current study aimed to assess the insecticidal effects, antifeedant and repellent activities of five essential oils; peppermint (Mentha piperita), cinnamon (Cinnamomum verum), neem (Azadirachta indica), camphor (Cinnamomum camphora) and lavender (Lavandula angustifolia) against the 4th instar larvae of the fall armyworm, Spodoptera frugiperda, under laboratory conditions, five concentrations of each oil, 10%, 5%, 2.5%, 1.25% and 0.625% (v/v) were used for these experiments. The toxicity results indicated that among all treatments, neem oil demonstrated the highest effectiveness, followed by cinnamon, peppermint, lavender and ultimately camphor oil with LC50 values recorded at 0.362, 0.729, 1.736, 5.704 and 11.578%, respectively. In case of antifeedant activities for the five oils it can be concluded that peppermint oil comes in first place as an antifeedant agent with feeding deterrence index )FDI) reached to 71.76% after 24h post-treatment followed by neem oil which recorded FDI reached to 58.97% followed by camphor, cinnamon oils and finally lavender oil as the FDI values lasted 40.21%, 24.67 and 10.34%, respectively. The repellency percentages of tested oils were increased based on exposure period and concentration, as neem oil had demonstrated the highest repellency percentage of 100% after 3h post-treatment at concentration 10% and after 24h of treatment at 5% concentration, while the cinnamon oil recorded 100% repellency after 24h at 10% concentration.