With top-dieback, the plant dies from the top down, with the upper leaves turning yellow or reddish purple, then drying out. When these leaves are removed or fall off, typical black anthracnose lesions can often be seen on the outside of the upper stalk. If the stalk is split, the pith appears rotted in the upper internodes. Late-season stress triggers the development of disease symptoms. Anthracnose symptoms may appear at the stalk base or on the upper stalk.
Stalk rot .
Some plants are dying because the base of their stalk is rotted by C. graminicola , Gibberella , or Fusarium . The onset of these stalk rots is also stress related. When the stalk base is rotted, the whole plant wilts and dies rather suddenly. To see the symptoms, you may need to split the stalk all the way the base, below the soil line. Decay of stalk base caused by Fusarium .