Some aphids may attack the bases of stems or the roots. Corn leaf aphids are found in colonies on stems and upper leaves of barley and corn, secreting much sticky honeydew. English grain aphids are found in colonies or scattered on leaves, stems, or in the heads of cereals and cultivated grasses. Greenbugs are found in colonies on leaves of cereals. Oat birdcherry aphids are found in colonies or scattered on lower leaves, stems, and roots of cereals and grasses.
Pea aphids are common wherever legumes are grown, especially in the Red River Valley of Manitoba.
Potato aphids, in addition to being found in potato fields, are becoming increasingly common in flax fields in Manitoba. Russian wheat aphids have not yet been reported from Manitoba. In Manitoba, aphids can be a problem on small grains. Corn leaf aphids feed on barley and corn in Manitoba. Occasionally, it is found on voluntary wheat and oats.