What is a primary use of nematicides?

Nematicides are primarily used to manage nematodes, which are microscopic worms that can cause significant damage to a variety of crops. The correct answer reflects that nematicides are typically employed as a preventive measure to inhibit nematode populations before they can inflict harm on plants.

Using nematicides preventively allows growers to protect their crops from potential infestations, thereby ensuring healthier yields and reducing the risk of damage before it occurs. While some nematicides can also be used curatively in response to an existing infestation, their most effective application is often preventative, making it critical to understand when and how to apply these substances in the crop management process.

The other options are less accurate in this context. Nematicides are not exclusively used as fumigants; they can be formulated in various ways, including granules, liquids, and emulsifiable concentrates, allowing for diverse application methods. Additionally, nematicides do not target fungal diseases; they are specifically formulated to combat nematodes, thus distinguishing their use within integrated pest management practices.