Insecticidal Activity of Lectin Preparations from Moringa oleifera Lam. (Moringaceae) Seeds Against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae)

The lesser mealworm, <i>Alphitobius diaperinus</i>, is a widespread pest in poultry farming, causing economic losses and facilitating the spread of pathogens. Current control methods rely heavily on synthetic insecticides, which raise environmental concerns and contribute to resistance. This study investigated the insecticidal potential of <i>Moringa oleifera</i> seed preparations, including an aqueous extract (AE), a protein-enriched fraction (PF), and an isolated lectin (WSMoL), against <i>A. diaperinus</i>. Contact assays demonstrated that AE and PF reduced adult survival by up to 90% and 100%, respectively, while WSMoL was effective only against larvae, causing 48% mortality. Ingestion assays showed that AE and PF reduced adult survival by 60% and 30%, respectively; impaired diet utilization; and caused significant weight loss. WSMoL exhibited antinutritional effects, including a 94% reduction in trypsin-like activity, but did not cause lethality, although it may impair long-term survival. Midgut histological analysis revealed epithelial disorganization, vacuolization, and nuclear condensation in the treated insects. These findings suggest that <i>M. oleifera</i> seed preparations are promising candidates for sustainable pest control, offering both lethal and sublethal effects on <i>A. diaperinus</i>. Future research should focus on the development of formulations and long-term impact assessments on pest populations and non-target organisms, paving the way for eco-friendly alternatives in integrated pest management.