Symptoms

The role of this insect as a vector of the sugarcane mosaic virus, maize dwarf mosaic virus, and maize leaf-fleck virus makes it a pest of considerable economic importance. Diseased plants may become stunted, show a conspicuous yellowish mottling, and turn reddish as they mature. Young plants that have been infected seldom produce ears.

Piercing of the leaves and sucking of plant fluids by the insect causes some yellowish mottling, but this damage is seldom of economic importance. Sugary droplets excreted by the aphids favor the development of black molds and make the plants sticky. These insects usually attack maize plants at the end of the midwhorl stage. Their colonies may completely cover emerging tassels and the surrounding leaves, preventing pollen release. In severe outbreaks the ear shoot is also infested, and seed set may be affected.

Description and life cycle

The small, greenish blue adults females do not lay eggs but give birth to nymphs. In crowded colonies winged forms are produced that eventually migrate to other plants. Skins that have been shed give the colonies a whitish appearance.