Nematicides

Nematicides are pesticides used to control nematodes, especially plant-parasitic nematodes that attack roots and reduce crop yields. They encompass chemical compounds, biological agents, and cultural methods applied to soil or plant surfaces to suppress nematode populations.

Chemical nematicides include soil fumigants such as chloropicrin and 1,3-dichloropropene, as well as non-fumigant compounds like metam sodium, oxamyl, and fosthiazate. Fumigants diffuse through soil and kill multiple life stages, while non-fumigants typically act as neurotoxins or metabolic inhibitors upon contact. Timing and method of application, such as pre-plant soil treatment or root-zone drenches, are key to effectiveness and safety.

Biological and naturally derived nematicides use living organisms or natural products to suppress nematodes. Examples include bacteria and fungi that parasitize nematodes or compete in the rhizosphere, as well as nematophagous fungi and Pasteuria spores. Plant-derived compounds and certain microbial products are also used as part of integrated pest management.

Environmental and regulatory considerations are important in nematicide use. Many products pose risks to non-target organisms, beneficial soil biota, and groundwater; chronic exposure can raise safety concerns for workers and ecosystems. Resistance and quota restrictions can limit effectiveness, necessitating rotation and integration with cultural controls such as resistant host varieties, crop rotation, and soil health management.

Nematicides are most common in high-value crops, vegetables, and ornamentals, where soilborne nematodes are a persistent problem. They are typically used under strict regulatory labels and safety guidelines to minimize environmental and human health risks.