Facile fabrication of a fungicide and plant immune inducer co-delivery nanosystem for enhanced control efficacy against plant disease

A stimuli-responsive co-delivery nanosystem for site-specific release of two or more pesticides with different mechanisms of action holds vast promise for enhanced control efficacy against agricultural pests. In this work, taking Zn-Al hydrotalcite (HTlc)-like nanosheet as the carrier, FEN/SA@HTlc was fabricated by a facile one-step method without heating and organic solvents to co-deliver hydrophobic fungicide (fenhexamid, FEN) and plant immune inducer (salicylic acid, SA) in a plant disease microenvironment responsive manner for dual-mode synergetic control of Sclerotinia disease in vivo. The loading amounts of FEN and SA in HTlc could be precisely controlled by adjusting the molar feed ratio between FEN and SA. The obtained FEN/SA@HTlc had nanosheet morphology, narrow particle size distribution (approximately 314 nm), and positive surface charge (+31.4 mV), and could intelligently co-deliver FEN and SA in respond to oxalic acid which is the pathogenicity factor of many plant phytopathogenic fungi. The photodegradation half-life of FEN/SA@HTlc (17.6 min) increased by 3.9 times compared with free FEN (4.56 min). In vivo control efficacy evaluations demonstrated an enhanced control efficacy, long protection duration, and desirable biosafety of FEN/SA@HTlc. This fungicide and plant immune inducer co-delivery nanosystem would provide new perspective for multimode synergetic nanopesticide design and sustainable plant disease management.