Effects of zinc oxide submicron particles and nanoparticles on the inhibition of Botrytis cinerea, Fusarium oxysporum and Alternaria alternata

Abstract Zinc oxide nanoparticles (ZnO NPs) exhibit antifungal properties and may be applied for limitation of pathogen growth in crop production. The objectives of the study were: 1) to investigate and compare the effects of ZnO submicron particles (ZnO SMPs) and ZnO nanoparticles (ZnO NPs) on the in vitro response of Botrytis cinerea , Fusarium oxysporum, and Alternaria alternata and 2) to evaluate the impact of those particles on suppressing disease symptoms caused by the three plant pathogens on potted tomato plants ( Solanum lycopersicum L. ‘Bawole Serce’). In the in vitro experiment ZnO SMPs or ZnO NPs at the concentration of 0, 100, 200, 500, 1000, and 2000 mg/l were applied. In the in vivo experiment, potted tomato plants were infected with pathogens and sprayed with ZnO SMPs or ZnO NPs suspensions at the concentration of 500 mg/l. Experimental objects included also non-infected control plants, as well as infected and ZnO SMPs/NPs non-treated control plants. The addition of ZnO NPs and ZnO SMPs to the PDA medium significantly inhibited the growth of mycelium of all tested pathogens. However, the advantage of ZnO NPs over ZnO SMPs in inhibiting the growth of mycelium has not been demonstrated. Interestingly, the lowest tested ZnO SMPs/NPs concentration (100 mg/l) caused a significant reduction of mycelium growth of F. oxysporum and A. alternata (up to 33.32%). As for B. cinerea , only the concentration of 500 mg/l and higher concentrations of tested material samples limited the growth of its mycelium (up to 82.67%). In vivo experiment on tomato plants did not confirm the effectiveness of ZnO SMPs in the reduction of B. cinerea and A. alternata infection, in contrast to ZnO NPs, which significantly limited the growth of all pathogens (by between 56.99% and 65.11%).