The disease develops on all above-ground plant parts. Yellow flecks generally appear first on lower leaves.
Infections, which are initially water soaked, will become dry, yellow and finally red-brown. Tiny black pepper-like dots (reproductive structures called pycnidia) may appear in the infected areas. L. nodorum most often causes blotches on the glumes and stem nodes rather than on the leaves. Infections begin at the glume tips and work downward and form purplish areas that later produce the dark, characteristic pycnidia.