Loose smut is one of the most common and easily recognized diseases of small grains.
Soon after flowering, small grain heads infected with loose smut can be readily observed in the field from several yards away by their characteristic blackened, smut-like spikes. However, loose smut rarely causes much damage to small grain. Losses to this disease rarely exceed 5 percent in yield reduction. They are host specific. This means that loose smut of barley and wheat attacks barley and wheat only and loose smut of barley and oats is specific to those two crops.