1. Department of Entomology and Plant Pathology; The University of Tennessee; Knoxville TN 37996 USA
2. United States Department of Agriculture-Agricultural Research Service and Department of Crop Sciences; University of Illinois; Urbana IL 61801 USA
3. Department of Plant Pathology, Physiology and Weed Science; Virginia Tech; Blacksburg VA 24061 USA
4. Department of Plant Pathology and Microbiology; Iowa State University; Ames IA 50011 USA
5. Department of Crop and Soil Environmental Sciences; Virginia Tech; Blacksburg VA 24061 USA