Disease is a major factor limiting yield of wheat in midwestern states. It ranks with weather, nutrition, cultivar and type of cultivation as a significant factor affecting yield potential. In the humid Midwest, losses as high as 20-40% have been reported in locations where disease control has not been practiced. Fortunately, most grain producers use sound disease control practices. The use of modem high yielding varieties, crop rotation, delayed planting date, and balanced fertility are well accepted agronomic practices that significantly limit the extent of yield losses due to disease.