Near-infrared-responsive CuS@Cu-MOF nanocomposite with high foliar retention and extended persistence for controlling strawberry anthracnose

Abstract

Strawberry anthracnose (Colletotrichum gloeosporioides) exhibits a high pathogenicity, capable of directly infecting leaves through natural openings, resulting in devastating impacts on strawberries. Here, nanocomposite (CuS@Cu-MOF) was prepared with a high photothermal conversion efficiency of 35.3% and a strong response to near-infrared light (NIR) by locally growing CuS nanoparticles on the surface of a copper-based metal-organic framework (Cu-MOF) through in situ sulfurization. The porosity of Cu-MOF facilitated efficient encapsulation of the pesticide difenoconazole within CuS@Cu-MOF (DIF/CuS@Cu-MOF), achieving a loading potential of 19.18 ± 1.07%. Under NIR light irradiation, DIF/CuS@Cu-MOF showed an explosive release of DIF, which was 2.7 times higher than that under dark conditions. DIF/CuS@Cu-MOF exhibited a 43.9% increase in efficacy against C. gloeosporioides compared to difenoconazole microemulsion (DIF ME), demonstrating prolonged effectiveness. The EC50 values for DIF and DIF/CuS@Cu-MOF were 0.219 and 0.189 μg/mL, respectively. Confocal laser scanning microscopy demonstrated that the fluorescently labeled CuS@Cu-MOF acted as a penetrative carrier for the uptake of hyphae. Furthermore, DIF/CuS@Cu-MOF exhibited more substantial resistance to rainwater wash-off than DIF ME, with retention levels on the surfaces of cucumber leaves (hydrophilicity) and peanut leaves (hydrophobicity) increasing by 36.5-fold and 9.4-fold, respectively. These findings underscore the potential of nanocomposite to enhance pesticide utilization efficiency and leaf retention.