• Large, greyish-brownish spots develop on the uppermost leaf sheaths enclosing the panicles.
• The young panicles remain in the leaf sheaths or emerge only partially. Grains remain unfilled or are discolored.
• Sheath rot can be confused with sheath blight. The symptoms are similar when the plants are young, and the damage is about the same.
• Hot, humid weather, as in forest areas, favors sheath rot.