Thiamethoxam loaded glycine/iron(III) controlled‐release granules: enhanced pesticide utilization rate and improved crop physiological status

Neonicotinoid pesticides have attracted much attention in pest control due to their excellent systemic properties and high insecticidal activity. Functional carriers based on controlled-release technology can precisely regulate the release of pesticides, improve utilization rate and reduce environmental risks, and have become an important research direction for optimizing root application strategies. In this study, thiamethoxam (TMX) was employed as a model pesticide. A dual binding strategy was adopted to prepare TMX core-shell controlled-release granules (TMX-GR). By adjusting parameters such as iron(III) concentration, glycine (Gly) concentration, material ratio, and particle size, products with distinct release properties were successfully fabricated. The results showed that the TMX-GR prepared successfully had a pesticide-loading efficiency of 50.30% and exhibited obvious controlled-release behavior. Glasshouse potted plants showed that the TMX-GR were more persistent and significantly improved pesticide utilization rate compared to 30% TMX suspension concentrate (30% SC) and 3% TMX granules (3% SP). In addition, the addition of Gly can improve the growth state of Brassica oleracea var. capitata L. seedlings and significantly increase the dry weight and soluble sugar content. In summary, this delivery system has a simple preparation process, demonstrating both excellent insecticidal activity and plant growth-regulation functions, thereby providing an innovative design concept for developing functional controlled-release formulations.