Symptoms of barley yellow dwarf vary with crop and variety. In wheat, the most common symptoms include a yellow to red discoloration that begins at leaf tip or margins and progresses toward the base of the leaf (Figure 1). The last leaf of the crop, often referred to as the flag leaf, may become prominently discolored and retain an upright posture. When infection takes place at early growth stages, plants often become severely stunted and produce heads of reduced size. Infected barley plants frequently become golden yellow in color. In oats, the virus produces a distinctive red discoloration of leaves.