Ph.D. Extension Specialist in Plant Pathology Nematodes are microscopic worms that are associated with plants and soil.
Most nematodes feed on debris and other microorganisms.
A few species, however, can cause substantial damage to plants by feeding on living roots or foliage. Although all soils contain nematodes, not all nematodes cause plant disease. Moreover, plant parasitic nematodes usually occur in populations that are too small to result in plant injury. To determine whether populations of nematodes are high enough to cause noticeable plant injury in commercial or residential plantings, send soil or plant samples to a nematode detection laboratory for analysis. Areas that are different in slope, drainage, and soil type should be sampled and tested separately.