Repellency, Fumigant Toxicity, Antifeedent and Residual Activities of Coridothymus capitatus and Its Main Component Carvacrol against Red Flour Beetle

Abstract

<i>Tribolium castaneum</i> is a challenging pest of stored products, causing significant economic losses. The present study explored the efficacy of <i>Coridothymus capitatus</i> essential oil and its primary constituent, carvacrol, as eco-friendly alternatives for managing this pest. To evaluate their insecticidal potential, repellency, fumigant toxicity, and antifeedant properties, progeny inhibition assays were performed. Carvacrol exhibited superior repellency compared to the essential oil, achieving a 92% repellency rate at 2 mg/cm². Both compounds demonstrated significant fumigant toxicity against <i>T. castaneum</i>, with LC₅₀ values of 168.47 and 106.5 μL/L for the essential oil and carvacrol, respectively, after 24 h. Carvacrol also outperformed the essential oil in antifeedant activity, inducing an 80.7% feeding deterrence at 1.17 mg/g. Moreover, both treatments effectively suppressed the development of the pest's progeny. These results collectively underscore the potent insecticidal properties of <i>C. capitatus</i> essential oil and carvacrol, particularly carvacrol, as promising candidates for the sustainable management of <i>T. castaneum</i> in stored product protection.