An Iron-Based Metal–Organic Framework as Nanocarrier for Lambda-Cyhalothrin Delivery: pH-Responsive Controlled Release, Enhanced Leaf Adhesion, and Prolonged Duration Period against <i>Culex pipiens pallens</i>

Lambda-Cyhalothrin (LC) is a high-efficiency and broad-spectrum insecticide. However, due to its poor water dispersion stability and unstable efficacy, it has many problems in practical applications. Therefore, there is an urgent need to develop new formulations with stability, low toxicity, and environmental friendliness to overcome the drawbacks of traditional pesticide formulations. This study designed an iron-based metal-organic framework (MIL-101(Fe)) as a nanocarrier for the loading of LC and then surface modified it with polydopamine (PDA) to form the nanopesticide PDA-LC-MIL. The results showed that PDA-LC-MIL has good stability and can achieve controlled release of pesticide by adjusting the pH value. In addition, it also has a good leaf affinity and can effectively adhere on crop leaves, improving the utilization rate of pesticides. The insecticidal experimental results indicate that PDA-LC-MIL has significantly improved sustained insecticidal activity. PDA-LC-MIL also has good biocompatibility and shows no significant inhibitory effect on seed germination and seedling growth of <i>Vigna radiata</i> (L.) <i>Wilczek and maize</i>. Therefore, we firmly believe that MIL-based nanopesticides will have broad application prospects in the field of green pesticides and modern agriculture.