INCIDENCE OF WESTERN CORN-ROOTWORM BEETLES (COLEOPTERA, CHRYSOMELIDAE) ON CORN IN VIRGINIA FROM 1987 TO 1992

The discovery of western corn rootworm beetles, Diabrotica virgifera virgifera LeConte, in a southwest Virginia corn field in 1985 prompted annual surveys of com fields in an average of 28 counties across the state from 1987 to 1992. All counties included in the annual surveys were representative of the major corn-growing regions of Virginia. Survey results indicated that western corn rootworm beetles spread rapidly throughout most of the western and central continuous corn-growing regions of the state. In the eastern and southeastern corn-growing regions of the state, where crop rotation is widely practiced, detections of western corn rootworm beetles were less common and typically involved only one to two counties per year from 1987 to 1992.