A dual pesticide–fertilizer silicon-base nanocomposite to synergistically control fungal disease and provide nutrition

The mixed utilization of pesticides and fertilizers plays an important role in the prevention of plant diseases and in providing nutrients for crop growth. The combination of pesticides with different mechanisms of action can achieve synergistic effects on plant disease control compared to the long-term use of a single pesticide. Herein, a pH-responsive dual pesticide–fertilizer silicon-base nanocomposite was fabricated. Copper ions (Cu²⁺) were integrated as metal nodes into mesoporous silica nanocarriers (Cu-MSNs), and zinc oxide (ZnO) quantum dots as nanocaps were grafted onto aminated Cu-MSNs by a Schiff base. The fungicides prochloraz (Pro) and hymexazol (Hym) were simultaneously encapsulated in Cu-MSNs, with loading rates of 11.42% and 14.71%, respectively. The Pro@Cu-MSNs-ZnO/Hym nanoparticles (Nps) had a rod-like structure with a particle size of 499.4 ± 7.88 nm and a low polymer dispersity index (PDI) of 0.17 ± 0.03. The Nps possessed excellent acid-responsive controlled release behavior, gradually self-degrading within 72 h and being absorbed by the crop. The inhibitory action of the Nps on Rhizoctonia solani (R. solani) was dependent on the concentration and showed good synergistic effects based on the physical mixture of Pro and Hym (1 : 1.29). Nps promoted plant growth by delivering metal elements and increasing the chlorophyll and cellulose content. The biosafety evaluation further indicated that the Nps had good biocompatibility and reduced the risk to the environment. Therefore, this new nanopesticide–fertilizer complex has potential application value in the development of sustainable agriculture.