Two Birds with One Stone: Eco‐Friendly Nano‐Formulation Endows a Commercial Fungicide with Excellent Insecticidal Activity

Abstract The development of multi‐action pesticides presents significant advantages, including cost‐effectiveness, reduced application frequency, enhanced resistance management, and minimized environmental impact. Despite its efficacy in targeting chitin synthase in both fungi and insects, the insecticidal performance of polyoxin B remains limited. To overcome this limitation, a novel nano‐formulation, polyoxin B@ZTS is developed, utilizing agricultural byproducts, tea saponin, and zein. This formulation features a small particle size, high leaf deposition efficiency, and excellent dispersion properties. Leveraging a disulfide bond system, polyoxin B@ZTS is designed to respond to the intracellular reducing environment, enabling controlled release of polyoxin B. Remarkably, the nano‐formulation facilitates the penetration of physiological barriers, achieving equivalent insecticidal and fungicidal efficacy to polyoxin B at only one‐fifth of the dosage. This work highlights the potential of eco‐friendly, cost‐effective, and multifunctional nano‐pesticides, providing a compelling solution for sustainable agricultural practices and demonstrating broad applicability in integrated pest and disease management.