In the colonies, nymphs, adult wingless females, and winged females may be present at the same time. The winged females usually are not present unless the colony is fairly large and somewhat crowded. The aphids disappear from the plants when the leaves start drying or at the onset of cold weather. Their tiny, white, flakey cast skins may remain on the plants for several months. The infested tassels become covered with a sticky substance called honeydew that drips onto the leaves and silks.
Pollination probably is affected by honeydew covered silks.
Heavily infested leaves and tassels may wilt and turn brown. A few weeks after the initial infestation, plants will have a black, sooty appearance due to a sooty fungus that develops and thrives on the honeydew excreted by the aphids. Although a few colonies of corn leaf aphids are present in just about every corn field in the state each year, their damage is generally of little economic importance except in seed corn production. Corn leaf aphid populations normally are controlled by environmental factors, several parasitic wasps, a fungal disease, lady beetles, syrphid fly larvae, and lacewing larvae and adults. Corn plants are most frequently injured by the aphids during the late whorl or pollen shed stage.