Étude de l’efficacité insecticide in vitro de Zilla macroptera contre l’insecte Tribolium castaneum

Abstract

As part of the valorization of Saharan plants and the search for natural alternatives to chemical insecticides, this study aimed to evaluate the insecticidal activity of aqueous and methanolic extracts of Zilla macroptera against adults of Tribolium castaneum (Coleoptera: Tenebrionidae), a major pest of stored food products. The extracts were obtained by maceration and applied using two methods: direct contact and ingestion. The insecticidal effect was assessed under in vitro conditions. Bioassays were carried out using different concentrations (20, 40, 60 mg/ml) over exposure periods of up to 10 days. The main evaluated parameters were lethal doses (DL25, DL50, DL90) and lethal times (TL25, TL50, TL90). The results showed that insecticidal efficacy was influenced by the applied concentration, solvent type, and mode of application. The methanolic extract demonstrated greater toxicity at lower doses, while the aqueous extract acted more rapidly at high concentrations. In contrast, ingestion resulted in very low efficacy, with TL50 values exceeding several hundred hours, indicating limited digestive bioavailability. However, contact application produced significant mortality rates starting from the fifth day of exposure. These findings highlight the insecticidal potential of Zilla macroptera and support its use in developing natural plant-based insecticides within an environmentally friendly biological control strategy. Further studies are recommended to identify the active compounds responsible for the observed toxicity