English Grain Aphid

Sitobion avenae

English grain aphids on a head of wheat
English grain aphids on a head of wheat. Photo courtesy of Dominique Jacquin. Licensed under CC BY-SA 3.0.
English grain aphids are a tiny pest of small grains and are found throughout the grain growing regions of the United States and Canada. Like other aphids, they have short generation times and their population can grow rapidly under the right conditions.
Adult english grain aphids are green or brown in color. Nymphs are similar in appearance but slightly smaller.
English grain aphids feed on the leaves of small grains, sucking the plant juices and weakening on the plant. Once the plant heads, the aphids feed directly on the developing kernels, reducing yield. They are also a vector for the barely yellow dwarf virus.
Insecticides are available for controlling english grain aphids. Always read and follow all label instructions.