Bipolaris sorokiniana (Sacc.)Shoemaker

1. Symptoms: Lesions caused by this disease are elongated to oval in shape and are generally a dark brown color. As lesions mature, the centers often turn a light brown to tan color, surrounded by an irregular dark brown ring (leaf picture; spike picture).
2. Development: Primary infections tend to be on the lower leaves, beginning as chlorotic flecks or spots. These infection sites enlarge, turn dark brown, and often coalesce. When the disease is severe, affected leaves or leaf sheaths may die prematurely.
3. Hosts/Distribution: Spot blotch affects wheat, triticale, barley, and most grasses. It is found worldwide, but is especially prevalent in more humid and higher rainfall areas.
4. Importance: If infection occurs early in the crop cycle and conditions remain favorable for development, complete defoliation is possible; major reductions in yield and severely shriveled kernels will then result.