Corn Leaf Aphid


Aphids are small, pear-shaped insects with soft bodies. They vary from blue-green to gray and have piercing-sucking mouthparts. They occur in sometimes very dense clusters on the plant. Most aphids in the cluster will be

Corn leaf aphid

Corn leaf aphid

University of Kentucky Dept. Entomology

wingless, but some may have small, clear wings.


Corn becomes stunted or wilted, especially when plants are under drought stress. Aphids secrete a sugary substance known as "honeydew". Tassels of moderately to heavily infested plants may be quite sticky from accumulations of secretion. Aphids cause the greatest damage while feeding in the whorl.

Pest Activity

Please note: No pest activity data currently available for corn leaf aphid. You may wish to contact your county extension agent or agricultural consultant for information tailored to your locality.

IPM Techniques and Scouting Procedures

  • Corn leaf aphids may be found from about four weeks prior to tasseling through tasseling. Begin scouting about three weeks prior to tasseling.
  • Examine 20 plants per each location. Rate infestations on each plant using the following rating scale:

0 - no aphids

l - l to 10 aphids/whorl

2 - more than 10 to 20 aphids/whorl

3 - more than 30 aphids/whorl

  • Aphids occur in clusters in the curl of leaves, in the whorl or on unemerged tassels. Check also for discolored brown or golden aphids. These are diseased or parasitized. Record these observation. Note if aphids are located below the ear zone on the plant or if they are a discolored brown or golden color.
  • Economic Threshold: Consider treatment if there are more than 15 aphids per whorl about three weeks before tasseling. (10 per whorl if plants are stressed from lack of moisture). BUT if plants are not under drought stress and you find 10 or more predators on each plant, controls probably are not justified. It is doubtful if treatment pays after 50% of the tassels have emerged.

References and Additional Information

Corn Diseases and Corn Insects Menu