Plant-parasitic nematodes can damage corn, and several instances of this are discovered each year in Iowa. More frequent cropping of corn following corn and less frequent use of soil-applied insecticides, which may have provided some nematode control in the past, could result in more instances of nematode damage to corn this year and in the future. For most plant-parasitic nematodes that feed on corn, numbers increase through the first half of the growing season. And samples should be collected midseason, when nematode numbers likely are greatest, so that the numbers can be compared to damage thresholds established for corn.