Adults:
Corn leaf aphids are soft-bodied, oval, and greenish or greenish-blue in color. They have black antennae, legs and cornicles ("tail pipes"), and are about the size of a pinhead (~2 mm long). The head has 2 longitudinal dark bands, and there is a row of black spots on each side. The body often appears to have a powdery coating. Winged and wingless females may occur, but males are rarely found. Females give birth to living young called nymphs without mating.

Eggs:
Eggs do not occur since the aphids give birth to living young.

Nymphs:
The nymphs resemble the adults but are smaller, with no wings.