Post-seedling infections are progressively less severe to the point where only the upper leaves, or the flag leaves, show discoloration. Mildly infected wheat may not show any discoloration. The leaves of plants infected with barley yellow dwarf virus are shorter than normal, and the flag leaf may be severely shortened. Leaves often are stiffer and more erect. Root systems are reduced and diseased plants are more easily pulled than healthy plants.
Stunted plants result from the failure of the stem internode to elongate.
Even the head, or panicle, doesn't emerge fully or properly. Patterns of barley yellow dwarf in a field either may be seen as random within the crop or as circular or angular patches which reflect the pattern of movement of the aphid vectors or carriers. Many of the infected plants ripen prematurely, after which they may be invaded by sooty molds which give a dirty appearance to the plants and may lower germination of harvested seed. Necrotic brown flecking or spotting may accompany the yellowing. Symptoms of barley yellow dwarf on barley.