The tightly rolled leaves protect the aphid from unfavorable weather, natural enemies and contact insecticides. Infestations may occur throughout wheat growth and development, but are less successful after head emergence. Damage severity is related to length of infestation. Early infestations often result in circular areas in the crop containing thin, stunted and discolored plants with rolled leaves. Severe infestations can cause stunted plants and heads, bleached heads containing poorly formed grain, and poorly emerged heads due to awns becoming trapped in the tightly rolled flag leaf.
Infestations often result in reduced grain yield and quality.
Russian wheat aphid does not transmit any important cereal diseases. Much of our biological knowledge is summarized above. In the Great Plains, migrants fly in from the south in the spring and are a threat to spring-planted crops, but most losses in winter grains are due to local overwintering populations. Biological control agents have been imported and released against Russian wheat aphid. Rolled leaves provide some protection against natural enemies.