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
4
th 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 posttreatment 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.
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