Toxic effects of Citrus aurantium and C. limon essential oils on Spodoptera frugiperda (Lepidoptera: Noctuidae).
Citrus aurantium and C. limon were selected in the search for natural plant insecticides. The essential oils of C. aurantium and C. limon and ethanol extracts of the seeds, pulp, albedo, and peel of C. aurantium were incorporated into the larval diet of the lepidopteran pest Spodoptera frugiperda. Larval and pupal mortality were quantified and adult malformation was observed. C. aurantium essential oil had antifeedant action and the mixture of albedo ethanol extract and C. aurantium essential oil had toxic effects on S. frugiperda larvae at early stages, when they had not yet produced major damage to the crop. Our results indicated that a mixture of ethanol extract of albedo and C. aurantium essential oil (250 µg of extract mix per g of diet) deterred feeding by 46% and had the highest larval mortality (100%) of the materials tested. The peel extract (250 µg per g of diet) produced an increment in growth rate and diet consumption. However, 40% of the larval and 45% of the pupal populations died after 96 h of treatment. The blend of essential oil and C. aurantium albedo ethanol extract showed the lowest consumption and a poor nutrient conversion into biomass. Finally, the presence of D-limonene and nootkatone in the peel ethanol extract, and C. limon and C. aurantium essential oils, may be the cause of the response in the feeding behavior and toxic effects found on S. frugiperda.