Background: Fluazaindolizine is a novel sulfonamide nematicide that is currently under commercialization in various countries. Four trials (two in tomato, two in zucchini) were carried out over two growing seasons in a root-knot nematode (RKN; Meloidogyne incognita)-infested plastic house to test the effects of a single application of fluazaindolizine at 1000 and 2000 g ha-1 , on RKN, the resident nematode community and to estimate any side effects on the soil food web and soil ecological functions. The composition of the nematode community was evaluated at three sampling times, pre-treatment (before soil preparation), at planting (after nematicide application) and at harvest. Nematode abundance and nematode-based ecological indices, such as maturity indices, soil food web indices (Structure, Basal, Enrichment index) and metabolic footprints were calculated and compared between the untreated and nematicide treatments at various sampling times.
Results: In both crops the test rates of fluazaindolizine significantly reduced both the soil numbers of RKN as well as the observed root galling at harvest. Fluazaindolizine treatments showed a low impact on the numbers of other plant-parasitic nematodes, and at harvest the numbers of some ectoparasites as Telotylenchus even showed higher values within the nematicide-treated plots than in the untreated control. Overall, fluazaindolizine treatments neither decreased the bacterivorous, fungivorous or omnivorous nematode densities, nor reduced the maturity and soil food web indices. However, we observed some slight reductions in the structure index as well as increases in the basal index that might indicate some adverse impact on soil functions resulting from the nematicide application. Still those impacts were considered small compared to the impact of the soil preparation.
Conclusions: Overall, fluazaindolizine showed a good level of selectivity towards RKN and therefore could become a useful tool within integrated nematode management approaches that also complements soil health and maintaining diversity in soil.
Keywords: nematicide; root-knot nematodes; soil food web; soil health.
© 2021 Society of Chemical Industry.