Which statement about nematodes is false?

• A. Nematodes are small, usually microscopic, roundworms
• B. It is easy for people to unknowingly spread them
• C. There are relatively few genera and species important to agricultural crop production
• D. The only effective way of determining the presence or distribution of nematodes is by soil and root tissue sampling.

Answer: (C)

Nematodes affecting crops come from a wide range of genera and species, and many of them are economically important. They are tiny, often microscopic roundworms that live in soil and on roots, and they spread easily through contaminated soil, water, plant material, and farming equipment. Because there are numerous genera and dozens of species that can damage different crops in different environments, it’s not accurate to say there are relatively few that matter.

Detection typically relies on sampling soil and root tissue to extract and identify nematodes, which is a primary method, but other diagnostic tools—such as molecular tests or bioassays—also play a role in confirming which nematodes are present and posing a risk.