Russian wheat aphid, Diuraphis noxia (Hemiptera: Aphididae), was first found in the U.S. in 1986, and is currently found in 16 western states (Fig. 1). In Utah, Russian wheat aphid was first detected in wheat and barley in San Juan County in 1987; now it is confirmed in every Utah county but Daggett, Piute, and Rich. Russian wheat aphids can build up to high numbers and cause significant plant damage.