Metal nanoparticles against fungicide resistance: alternatives or partners?

Chemical control suffers from the loss of available conventional active ingredients due to strict environmental safety regulations which, combined with the loss of fungicide efficacy due to resistance development, constitute major problems of contemporary crop protection. Metal‐containing nanoparticles (MNPs) appear to have all the credentials to be next‐generation, eco‐compatible fungicide alternatives and a valuable anti‐resistance management tool. Could the introduction of MNPs as nano‐fungicides be the answer to both reducing the environmental footprint of xenobiotics and dealing with fungicide resistance? The potential of MNPs to be utilized as nano‐fungicides, both as alternatives to conventional fungicides or/and as partners in combating fungicide resistance, is discussed in terms of effectiveness, potential antimicrobial mechanisms as well as synergy profiles with conventional fungicides. However, their “golden” potential to be used both as alternatives and partners of conventional fungicides to combat resistance and reduce environmental pollution is challenged by undesirable effects towards non‐target organisms such as phytotoxicity, toxicity to humans and environmental ecotoxicity, constituting risks that should be considered before their commercial introduction as nano‐pesticides at a large scale. © 2022 Society of Chemical Industry. Metal nanoparticles alone or combined with conventional fungicides demonstrate effectiveness against sensitive and fungicide‐resistant plant pathogens utilizing various mechanisms including: (i) enhanced membrane perturbation, (ii) disruption of ion homeostasis, (iii) inhibition of efflux pumps or (iv) detoxification enzymes, and (e) nanoparticle size reduction due to a “capping” effect.