Barley Yellow Dwarf

The disease can affect wheat, barley, and oats, resulting in yield losses ranging from 5 to 25 percent. The disease is often found at low levels in all areas of Pennsylvania, but severe epidemics have been reported. Outbreaks of barley yellow dwarf are often associated with warm fall and mild winter conditions that favor the spread of the disease to fall-sown small grain crops.

Symptoms

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.