Dark, dusty clouds are lingering behind many combines this fall as smut-infected ears are harvested. During the latter half of the season I received more calls than usual about this disease, and reports of smut have accelerated as some of the previously unnoticed fields were harvested. Common corn smut, caused by the fungus Ustilago zeae or Ustilago maydis, is a well-known disease that usually does not cause economic damage.