The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a major pest of wheat and barley in the southern and central Great Plains. Monetary losses to the pest nationwide averaged $127 million per year between 1987 and 1993.

Approximately 65% of total losses occurred in the 7 Great Plains states of Texas, Oklahoma, New Mexico, Colorado, Kansas, Nebraska, and Wyoming. Climate and the spatial and temporal availability of host plants play major roles in determining patterns of abundance and pest status of D. noxia in the Great Plains. Oversummering is limited by the abundance, spatial distribution, and seasonal growth patterns of noncultivated host plant species. Overwintering is limited primarily by the extremes and duration of cold. Even though landscape structure plays an important role in D. noxia population dynamics, determining and predicting how landscape structure and climate interact to produce observed patterns of abundance is difficult because of the number of interacting variables and the size and complexity of agricultural landscapes and the region as a whole. Spatially explicit population dynamics simulation models that extrapolate population processes to a landscape or larger geographic scale may play an important role in elucidating how the factors mentioned above interact to generate observed abundance patterns. Use of remotely sensed data, geographic information systems, and simulation modeling are required to develop spatially explicit population dynamics models to facilitate understanding of the aphid’s ecology. These models also may play a role in prediction and management of population outbreaks.