Fungicidal efficacy of chemically-produced copper nanoparticles against Penincillium digitatum and Fusarium solani on citrus fruit

The environmental problems caused by fungicides cannot be ignored. New eco-friendly and effective nano-agrochemicals as alternative chemical fungicides need to be explored. The fungicidal activity of copper nanoparticles (CuNps) was tested against Penicillium digitatum (green mold) and Fusarium solani (Fusarium rot) in vitro and in vivo. Fungal growth inhibition was observed in the presence of different concentrations of CuNPs, In vitro, a complete growth inhibition was recorder at 20 and 60 mug/mL for P. digitatum and F. solani, respectively. In vivo, CuNPs at 20 and 40 mug/mL were tested as direct and indirect action against green mold and Fusarium rot, respectively. These two concentrations completely inhibited the decay caused by both pathogens when pathogen and CuNPs were applied to the same wound (direct action). Fourier transform infrared (FTIR) spectroscopy identified the possible functional groups involved in the reduction and stabilization of CuNPs and the chemical composition of Cu. From the energy dispersive X-ray spectroscopy (EDX) spectrum, the formation of CuNPs was confirmed. The average particle size and distribution size were characterized by biophysical techniques such as Dynamic Light Scattering (DLS). Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). TEM revealed the presence of spherical CuNPs with size ranging from 45 to 48 nm in diameter. Also, the genotoxicity exhibited by CuNPs was demonstrated by degration of fungal DNA post-treatment even with concentrations at 20 and 40 mug/mL of the nanoparticles against P. digitatum and F. solani, respectively. CuNPs are low-cost effective and less toxic to humans and animals. Thus, they may be a very promising alternative to synthetic fungicides offering a protection against green mold and Fusarium rot of citrus fruit.