Corn, Zea mays L., is the most abundant field crop in Iowa, and there are many insect pests associated with this field crop. Although aphids are not typically economic important in corn, recent observations have indicated several species of aphids developing populations in northwest Iowa. The corn leaf aphid, Rhopalosiphum maidis (Hemiptera: Aphididae), has been the most abundant aphid species; however, the bird cherry oat aphid, Rhopalosiphum padi (Hemiptera: Aphididae), and several other species have also been detected in corn after tasseling. Damage potential and management guidelines for aphids in corn are not well defined and this research is aimed at developing economic threshold and sampling protocols.