Insecticidal Activity of Ficus carica, Eruca sativa, Portulaca oleracea, and Lupinus albus Against Adult Tribolium castaneum

Abstract

This study evaluated the insecticidal, repellent, and fumigant activities of four plant-derived extracts: Ficus carica (common fig), Eruca sativa (arugula), Portulaca oleracea (common purslane), and Lupinus albus (white lupin) against adult Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Gas chromatography–mass spectrometry (GC–MS) analyses identified key bioactive compounds, including unsaturated fatty acids, phytosterols, and tocopherols, which may contribute to their insecticidal and repellent properties. In the residual paper technique, F. carica extract exhibited the highest mortality (22% at 100 mg/mL), followed by E. sativa (14%) and L. albus (6%), while P. oleracea induced only 2% mortality. Repellency bioassays revealed strong deterrent effects, particularly for F. carica and E. sativa. After 3 h, F. carica exhibited 98% repellency at 2 mg/cm², maintaining 66% at 0.5 mg/cm² and 56% at 0.125 mg/cm², indicating broad-spectrum efficacy. E. sativa followed with 64% repellency at 2 mg/cm², sustaining over 50% repellency across all concentrations. Although repellency declined over time, F. carica retained 70% at 2 mg/cm² after 24 h, while E. sativa maintained 64% repellency. In contrast, L. albus and P. oleracea exhibited weaker repellency. These findings highlight the strong repellent effects of F. carica and E. sativa, suggesting their potential as natural alternatives to synthetic insecticides in stored grain pest management. Under fumigation conditions, F. carica, E. sativa, and P. oleracea exhibited minimal insecticidal activity, and L. albus had no measurable effect. These results indicate that the primary potential of F. carica and E. sativa lies in their strong repellency and moderate contact toxicity, rather than fumigation.