1. Department of Entomology, University of Minnesota , 219 Hodson Hall, 1980 Folwell Avenue, St. Paul, MN 55108 , USA
2. Department of Applied Economics, University of Minnesota , 231 Ruttan Hall, 1994 Buford Avenue, St. Paul, MN 55108 , USA
3. Extension Entomology, Department of Plant Pathology, North Dakota State University , 210 Walster Hall, Fargo, ND 58102 , USA
4. Department of Applied Ecology, North Carolina State University , Raleigh, NC 27695-7617 , USA