Interest in plant-parasitic nematodes as pests of corn in Iowa, and much of the Midwest, has increased dramatically in the past few years. Damage from these microscopic worms, which feed from within the roots and on the outside of roots, can cause overall stunting of the plant and yellowing of foliage. Ears may be stunted and poorly filled due to damage by this pest. Feeding by some nematode species also causes swelling of corn roots. None of these symptoms are unique and useful in identifying fields in which such damage is occurring.