Information gathered by Scott StoreyDrawings by Justin Spurlin

Rhopalosiphum padi

Physical CharacteristicsCan reduce forage and grain yields.Does not cause visible symptoms in the wheat but heavy infestations will cause plants to become sticky with honeydewVery efficient vector of the virus that causes Barley Yellow Dwarf disease DamageOlive-green color, has a red orange patch surrounding the base of each cornicle“Old” aphids found in winter or early spring Could be totally black in color, but will give birth to more typical aphids in the springMeasures about 1/8 inch long

Schizaphis graminum

Physical CharacteristicsLime-green colored Darker green stripe on its backOuter half of its antennae, outer half of its legs and the tips of its cornicles are blackMature greenbug measures about 1/16 inches long DamageCauses yellowing of young wheat leavesOrange-red spots on the leaves of older plantsOften occur in concentrated patches in the fieldDamage frequently occurs as small circular patches Can carry the virus causing Barley Yellow dwarf disease

Diuraphis noxia

Physical CharacteristicsLime green in color, “spindle shape”Short antennae, no prominent cornicles, a projection above “tail” giving a “double tail appearance” Mature RWA is about 1/16 of an inch longDamageSerious injury, yield loss even at low levels because it injects chemicals that affect plant growthAs it feeds, causes leaf to curl, creating an enclosure protecting it from climate, natural enemies, and insecticides. Symptoms become visible as white, yellow, or purple streaks

Sitobion avenae

Physical Characteristics Larger than greenbug, has a “spidery” appearance due to its long legs and long narrow cornicles Body is lime green, but legs and cornicles are black The English grain aphid is 1/8 inch long when mature.DamageMore common in the late growing seasonPrefers to feed on awns and wheat headsSeldom reduces yields, generally does not require controlIs vector virus that causes Barley Yellow Dwarf disease

Rhopalosiphum maidis

Physical CharacteristicsBluish-green with short black cornicles and black antennae and legsThe corn leaf aphid is not considered an economically important pest of wheat in Oklahoma. More commonly found in corn and sorghum, but may be found on seedling wheat in the autumn or on mature wheat late in the growing season.DamageIt is a known vector of the virus that causes Barley Yellow Dwarf disease

Identifying insect pests can help determine problems before they proliferate. Knowing the difference between pest insects and natural enemies can also help. To view the presentation on natural enemies, click here.