Advanced Formulation of Ecological Biopesticides Based on Citrus Limonum in Clayey Matrices: Optimization of Diffusive Dynamics

This study investigates the innovative use of natural porous clays from the Bejaad region in Morocco as a support matrix for the encapsulation and controlled release of lemon essential oil (Citrus limonum, EOCL), a natural compound with well-documented insecticidal properties. The research aims to address the inherent challenges of essential oils, particularly their high volatility and rapid degradation, by improving their stability and insecticidal efficiency against the grain pest Sitophilus granarius. By anchoring EOCL onto clay matrices, the study seeks to achieve a sustained and controlled release of the active components, thereby enhancing their practical application as biopesticides. The clays were comprehensively characterized using advanced analytical techniques, including X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX), and thermogravimetric analysis (TGA). These techniques revealed the mineralogical composition, thermal properties, and morphology of the clays, demonstrating their suitability for effectively adsorbing and retaining EOCL. The insecticidal performance of the clay/EOCL composites was rigorously tested under controlled conditions, revealing a marked improvement in efficacy, with significantly lower lethal doses required to achieve high mortality rates in Sitophilus granarius. The diffusion of EOCL through the clay matrix was modeled using Fick law of diffusion, and the results were further refined through statistical optimization to identify key parameters that influence the release and effectiveness of the active compounds. Complementing the experimental approach, a bioinformatics analysis was conducted to explore the molecular interactions between limonene, the primary active component of EOCL, and target proteins in insects. This theoretical investigation provided insights into the potential mechanisms of action, reinforcing the empirical findings. The study concludes that encapsulating EOCL within porous clay matrices not only enhances the stability and controlled release of the oil but also significantly boosts its insecticidal effectiveness. This approach presents a promising, environmentally sustainable strategy for crop protection, integrating material science, theoretical modeling, and bioinformatics to develop more efficient and durable biopesticides.