Tan Spot of Wheat

Tan spot is a major leafspot disease of winter wheat in the Great Plains of North America. It is more severe in wheat cropping systems that maintain crop residue on the soil surface. Although tan spot can be a serious threat by itself, it occurs more often as part of a foliar disease complex involving tan spot, leaf rust, and Septoria leaf blotch. Wheat, bromegrass and wheatgrass are the primary hosts for the this fungus. The disease progresses most rapidly in rainy, misty, or foggy weather, which allows spores to germinate and infect plants. Management options include crop rotation and foliar fungicides.