For a tabular Departmental chronology, Click here. Nematodes are a diverse group of roundworms that occur worldwide in virtually every environment.
Nematodes are second only to insects in the number of species in the animal kingdom.
However, only about 3 percent of all nematode species have been studied and identified. One cubic foot of soil may contain millions of individual nematodes belonging to several different taxonomic groups. Some of the best known nematodes are animal parasites such as heartworms, pinworms, and hookworms. Often, plant damage caused by nematodes is overlooked because the resulting nonspecific symptoms, such as slow growth, stunting, and yellowing, can also be attributed to nutritional and water-associated disorders. Many nematode species are beneficial to agricluture and the environment.