Effects of Silver, Gold, and Platinum Nanoparticles on Selected Nematode Trophic Groups

As trophic organisms, nematodes play an essential role in the soil environment: they mineralize nutrients into plant-available forms, are a food source for other soil organisms, and feed on pathogenic organisms and plant pests, therefore regulating populations of soil microorganisms. The plant-parasitic nematodes are important pests of crops. Nanoparticles (NP) are increasingly used in agriculture and other production sectors. They are present in the soil, not necessarily in trace amounts, and can affect various soil organisms, including nematodes. In this article, the effects of silver (Ag), gold (Au), and platinum (Pt) nanoparticles on the mortality and reproduction activity of selected nematode species from two trophic groups: entomopathogenic nematodes (EPN) (Heterorhabditis bacteriophora and Steinernema feltiae) and plant parasitic nematodes (PPN) (Xiphinema diversicaudatum, Ditylenchus dipsaci, Heterodera schachtii) were studied under laboratory conditions. All nanoparticles decreased the nematode population to an extent depending on the nematode species, nanoparticle type, and exposure time. AgNP had the greatest nematicidal effect, except for AuNP, which reduced the population of H. schachtii the most. The greatest sensitivity to AgNP was observed in X. diversicaudatum (100% mortality), D. dipsaci (90% mortality), and 37 to 13% mortality in other species. Effect of AuNP and PtNP on entomopathogenic nematodes was comparable to the control, not treated with nanoparticles. AuNP and PtNP similarly influenced nematode mortality. However, the effect of nanoparticles on new generations of entomopathogenic nematodes developing in host larvae Galleria mellonella was inconclusive. All nanoparticles decreased the number of larvae of S. feltiae and increased the number of H. bacteriophora migrating outside the cadavers compared to the control.