1. USDA-ARS, Sugarbeet Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, North Dakota, USA
2. USDA-ARS, Northwest Irrigation and Soils Research Laboratory, Kimberely, Idaho, USA
3. Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, USA
4. USDA-APHIS-Plant Germplasm Quarantine Program, Laurel, Maryland, USA