University of Illinois

No. 17/July 16, 1998

Watch for Corn Leaf Aphids

In last week's issue (no. 16, July 10, 1998) of the Bulletin, Mike Gray discussed several aspects of corn leaf aphids in corn, including life cycle, description, scouting procedures, thresholds, and suggested insecticides. Although he reported that we have not received many reports of heavy infestations of corn leaf aphids this year, he indicated that pockets of these pests could show up. During our recent "walks" through corn fields in east-central Illinois to assess corn rootworm larval injury in our on-farm trials, we observed an infestation of corn leaf aphids in one field in Iroquois County. Although a small percent of plants were infested, the tassels infested had colonies comprised of hundreds of aphids. Given the reproductive potential of aphids, their numbers can increase very rapidly. If the weather throughout July is hot and dry, corn growers might experience some localized outbreaks of corn leaf aphids.

Refer to last week's issue of the Bulletin for treatment guidelines and suggestions.

Kevin Steffey (, Extension Entomology, (217)333-6652