Ecological Impacts of Chemical Fumigants on Nematode Community Composition

ABSTRACT Soil fumigation is widely used to control targeted plant‐parasitic nematodes in agricultural systems, but how they affect nematode communities and nematode‐based indices (NBIs) has remained underexplored. This review examines the effects of common chemical fumigants, including methyl bromide, chloropicrin, 1,3‐dichloropropene, metam sodium, and dimethyl disulfide, on nematode trophic groups and soil food web dynamics. While these fumigants effectively suppress plant‐parasitic nematodes, they also negatively impact beneficial nematode groups such as fungivores, omnivores, and predators, reducing overall nematode diversity and ecological function. The structure index (SI) and maturity index (MI) often decline post‐fumigation, reflecting a shift toward a simplified and less stable soil ecosystem. Conversely, the basal index (BI) may increase, indicating a transition toward stress‐tolerant nematodes. Bacterivore populations tend to recover quickly due to bacterial proliferation, whereas fungivores, omnivores, and predators exhibit delayed or incomplete recovery, potentially altering nutrient cycling and natural pest control. Persistent declines in higher trophic groups weaken soil functionality and increase reliance on chemical inputs. Given these ecological consequences, integrating sustainable alternatives such as biofumigation, crop rotation, and organic amendments is essential to mitigate adverse effects. Future research should focus on long‐term community recovery, dose‐response relationships, and site‐specific impacts to refine fumigation practices and develop environmentally sustainable nematode management strategies.