A high adhesion co‐assembly based on myclobutanil and tannic acid for sustainable plant disease management

Abstract Background Pesticides are irreplaceable inputs for protecting crops from pests and improving crop yield and quality. Self‐assembly nanotechnology is a promising strategy by which to develop novel nano‐formulations for pesticides. Nano‐formulations improve the effective utilization of pesticides and reduce risks to the environment because of their eco‐friendly preparation, high drug loading, and desirable physicochemical properties. Here, to enhance the utilization efficiency of myclobutanil (MYC) and develop a novel nano‐formulation, carrier‐free co‐assembled nanoparticles (MT NPs) based on MYC and tannic acid (TA) were prepared by noncovalent molecular interactions using a green preparation process without any additives. Results The results showed that the prepared spherical nanoparticles had good stability in neutral and acidic aqueous solutions, low surface tension (40.53 mN m −1 ), high rainfastness, and good maximum retention values on plant leaves. Release of active ingredients from MT NPs could be regulated by altering the molar ratio of subassemblies in the co‐assembly and the pH of the environment. Antifungal experiments demonstrated that MT NPs had better activities against Alternaria alternata and Fusarium graminearum [half‐maximal effective concentration (EC 50 ) = 6.40 and 77.08 mg/L] compared with free MYC (EC 50 = 11.46 and 124.82 mg/L), TA (EC 50 = 251.19 and 503.81 mg/L), and an MYC + TA mixture (EC 50 = 9.62 and 136.21 mg/L). These results suggested that MYC and TA incorporated in the co‐assembled nanoparticles had a synergistic antifungal activity. The results of a genotoxicity assessment indicated that MT NPs could reduce the genotoxicity of MYC to plant cells. Conclusion Co‐assembled MT NPs with synergistic antifungal activity have outstanding potential for the management of plant diseases. © 2023 Society of Chemical Industry.