Effects of copper and silver nanoparticles on growth of selected species of pathogenic and wood-decay fungi in vitro

As research indicates a role for metal nanoparticles as fungicides, the work described here addresses the influence of copper nanoparticles (CuNPs) and silver nanoparticles (AgNPs) on the growth in vitro of pathogens causing damping-off as well as wood-decay fungi; i.e., Rhizoctonia solani (2 strains), Fusarium oxysporum, F. redolens and Phytophthora cactorum, along with Fistulina hepatica, Grifola frondosa, Meripilus giganteus and Sparassis crispa. Results indicate selective anti-fungal activity of the nanoparticles as applied at concentrations of 5, 15, 25 or 35 ppm. While neither nanoparticle affected P. cactorumor S. crispa, both inhibited growth in R. solani (strain 2), F. redolens and M. giganteus. R. solani (strain 1), F. oxysporum, F. hepatica and G. frondosa only showed sensitivity to higher concentrations of AgNPs, albeit with inhibitory impact on mycelial growth greater than with CuNPs. R. solani strains differed markedly in responses to both nanoparticles. Overall, the considerable toxicity of AgNPs and CuNPs to certain pathogens and wood-decay fungi indicates possible use in protecting nursery seedlings and safeguarding trees and wood, if with an awareness that certain fungi prove insensitive to both kinds of nanoparticle.