Copper Based Nanomaterials Suppress Root Fungal Disease in Watermelon (Citrullus lanatus): Role of Particle Morphology, Composition and Dissolution Behavior

Abstract

With increasing global population, innovations in agriculture will be essential for a sustainable food supply. We compare commercial CuO NP to synthesized Cu3(PO4)2·3H2O nanosheets to determine the influence of coordinating anion, particle morphology, and dissolution profile on Fusarium oxysporum f. sp. niveum induced disease in watermelon. Copper dissolution in organic acid solutions that mimic complexing agents found in plants was increased by 2 orders of magnitude relative to water. Cu3(PO4)2·3H2O nanosheets showed a rapid initial dissolution, with equilibration after 24 h; CuO NP exhibited continuous particle dissolution. In a greenhouse study, Cu3(PO4)2·3H2O nanosheets at 10 mg/L significantly repressed fungal disease as measured by yield and by a 58% decrease in disease progress. Conversely, CuO NP only yielded significant effects on disease at 1000 mg/L. In field studies, similar enhanced disease suppression was noted for Cu3(PO4)2·3H2O nanosheets, although biomass and yield effects were variable. ...