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About the Aphid

Aphids are soft bodied insects that are capable of multiplying rapidly. The most distinguishing characteristics that they possess are their stylet-like mouthparts and a pair of tubelike structures that project from their abdomen, called cornicles. Aphids may be winged or wingless and they usually reproduce asexually, giving birth to live young through a process called parthogenesis in which all the young are females. They grow by shedding their skin, which leaves a "ghost-like skeleton on the leaf.
Aphids feed by sucking plant juices. Some aphids like the Greenbug and Russian wheat aphid possess toxic substances in their saliva that causes the plant to become distorted or injured. Others are able to transmit plant diseases. Aphids have a number of natural enemies that hold down population increases.

Types of Aphids

There are five common aphids that attack winter wheat in the Great Plains. They are the Bird Cherry-Oat Aphid, the Corn Leaf Aphid, the English Grain Aphid, the Greenbug and the Russian Wheat Aphid.

Bird Cherry - Oat Aphid

Bird cherry-oat aphids (BCOA) occur in fall and spring. Wingless BCOA are distinguished from the greenbug by their olive-green color and the red-orange patch on the rear end of the aphid. "Old" BCOA found in winter and early spring may be totally black in color, but they will give birth to more typical aphids in the spring. The BCOA is a very efficient vector of the virus that causes barley yellow dwarf disease (BYD).

Corn Leaf Aphid

Corn leaf aphids are bluish-green, with black cornicles (tail pipe looking projections on the rear of the aphid) and black antennae and legs. They sometimes occur in seedling wheat in autumn or on mature wheat in late spring. Insecticidal control is never recommended for corn leaf aphids in wheat.

English Grain Aphid

English grain aphids are larger than greenbugs and have a "spidery" appearance due to their long legs and narrow, long cornicles (tail pipe looking projections on the rear of the aphid). The body of the English grain aphid is green, but the cornicles and much of the legs are black. The English grain aphid is commonly found in the heads of wheat but seldom reduces yield, and insecticidal control is not recommended.


The greenbug is lime-green colored with a darker green stripe running down the length of its back. The outer half of its antennae and tips of the legs are black, as are the tips of its cornicles (tail pipe looking projections on the rear of the aphid).

Russian Wheat Aphid

The Russian wheat aphid (RWA) occurs primarily in the Oklahoma Panhandle, and in the Texas and Colorado High Plains. It is pale green in color and "spindle shaped" with a waxy coating that gives it a powdery appearance. It does not have prominent cornicles (the tail pipe looking projections that occur on the rear end of the other aphid species that infest wheat). Damage symptoms appear as visible white, yellow, or purple longitudinal streaks on the leaves and stems of wheat plants.

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