Barley yellow dwarf (BYD) is a virus disease that can cause serious yield loss when stunted and discolored plants are widely distributed in a field. Severe losses due to BYD occur state-wide about every five years or so, but individual fields are impacted to varying degrees each year. There are many diseases that can reduce wheat yields, but in the case of BYD, most of the disease management decisions (such as field selection, tillage practices, variety, and planting date) are made by the time the seed is actually sown in the fall.