The western bean cutworm (WBC), once a pest of the High Plains, has been on the move since at least 2000. (See map below.) This native caterpillar pest of dry beans and corn has been expanding its range to the east through the Corn Belt. WBC spread across Iowa during 2000-2003 and was first recorded in Illinois and Missouri in 2004.
Available at: http://works.bepress.com/erin_hodgson/183/