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Plant-parasitic Nematodes in Canada Part 1

A large and thriving community of diminutive roundworms, or nematodes, lives within the soils of Canada. A few grams of soil from a garden, lawn, forest, or farm may contain scores of individual nematodes. Because of their transparent bodies and small size (seldom exceeding 2 mm in length and 0.04 mm in width), special extraction techniques are necessary to detect their presence in the soil. When they are isolated in a clear water suspension and observed under a microscope, a mixture of species appears that exhibits great diversity in form and purpose. Some kinds are highly adapted to feeding on microorganisms or the decomposition products of animals and plants: other species prey on other nematodes and on small invertebrates; occasionally they are parasites of insects; and, invariably, some species attack plants. Nematodes themselves may also be victims of fungal, viral, bacterial, protozoan, or invertebrate parasites. Consequently, the existence of nematodes in faunal communities is important for sustaining the structure and viability of the soil ecosystems. To the grower, however, nematodes are pests that create problems in plant management and production, particularly of nursery and agricultural crops.