Description: Several species of aphids are known to feed on and injure winter grains. Aphids are soft- bodied insects. The most common aphids found on winter grains in Georgia are the bird cherry-oat aphid, English grain aphid, corn leaf aphid and greenbug. Both the English grain aphid and the bird cherry-oat aphid have been identified to vector the disease, Barley Yellow Dwarf (BYD). The most prominent characteristic of aphids is the presence of cornicles located on the abdomen.

Hosts: Wheat, barley, oats, corn, winter grasses and some summer grains.

Damage: Grain aphids feed by piercing the plant and sucking out the plant juices. Aphids often congregate on new tissue and can be found deep within the plant near the growth whorl. Damaged plants will often curl, wilt, and may die during periods of weather extremes. Plants infested with BYD will appear stunted and yellowish-purple in color and are subject to environmental stress. Aphid feeding and disease damage can significantly reduce yields. The most significant yield reductions occur when aphid infections develop in the fall on winter grains.

Life Cycle: Grain aphids can overwinter extreme cold temperatures as eggs, late instar nymphs or adults. Overwintering progeny are all females that give birth to living young. This first spring progeny are all wingless females that also produce live progeny without mating. The summer generation is winged and may develop on corn, other grain or volunteer grasses. Winged male adults appear in the fall and mate with over-summered females. Each female aphid lays only about 8 eggs. It is believed as many as 17 generations may develop in a year.

Greenbugs on wheat
Photo by: Randy Hudson, UGA

Aphids of flagleaf wheat
Photo by: Randy Hudson, UGA

Aphid honeydew on wheat
Photo by: Randy Hudson, UGA