Clean seed severely and discard shriveled kernels. TAN SPOT, Pyrenophora tritici-repentis Symptoms. Elliptic or diamond shaped tan spots form on leaves, often with a yellow border and a small chocolate brown center. Survival and Spread . Survives on infected straw and stubble, on wild grasses, and rarely on seed.
Spores are airborne and also spread by splashing rain.
Other Crops Affected. Bromegrass, rye and wheat grass. Varieties vary in susceptibility. Check variety information publications for susceptibility to leaf spot fungi. Crop rotations or burying crop refuse by tillage reduces early infection but may not prevent late infection.