Potential for Using Four Plant Essential Oils to Protect Stored Products Against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Abstract

Food products that are kept in storage, such as grains, cereals, and processed foods, can sustain serious damage from stored-product insects. This study examined the effects of four essential oils (EOs) extracted from sweet violet (Viola odorata L.), parsley (Petroselinum crispum L.), neroli (Citrus aurantium amara), and marjoram (Origanum majorana) against red flour beetles Tribolium castaneum (L.) in terms of contact and fumigant toxicities, repellency, and antifeedant properties. The EOs of O. majorana and V. odorata had the highest contact toxicities against T. castaneum adults, with LC₅₀ of 5,313 mg/L and 5,512 mg/L, respectively. The EO of V. odorata showed the highest fumigant toxicity against adults of T. castaneum with an LC₅₀ of 491 mg/L after 48 hours of exposure. All tested EOs exhibited a repulsive effect against adults of T. castaneum. Rejection of the tested EOs increased with increasing concentrations and time of exposure, except for O. majorana. The lowest concentration of EOs extracted from P. crispum and O. majorana demonstrated feeding stimulatory effects over control, but C. aurantium showed the highest feeding deterrence index (FDI) value against adults of T. castaneum. The phagostimulant activity of O. majorana and P. crispum decreased linearly as the applied concentration of the EOs increased. The application of EOs resulted in a significant decrease in the number of emerged adults of new generation progeny (F₁); the reduction in F₁ exhibited a dose-dependent relationship. These findings highlight the prospective application of plant EOs as biocontrol agents against adults of T. castaneum.