Nematodes, microscopic roundworms that are practically everywhere, are one of nature's most interesting critters. Nematodes are ubiquitous in all of nature. Dozens of soil inhabiting nematodes can found in a single cup of soil. Most species of soil inhabiting nematode feed on dead plant material or other organic matter.
Some nematodes are predators that that feed on insects, protozoa, or other nematodes.
A relatively small number of nematode species are parasites of plants. Plant parasitic nematodes have a specialized organ called a stylet that allows them to puncture living cells and suck out the contents of the plant cell. Nematodes that feed on plant roots greatly destroy the ability of the plants to absorb water and nutrients. Sandy soils have a greater tendency to have high populations of plant parasitic nematodes than clay soils. The sting nematode is extremely harmful to most grasses.