Corn smut is a plant disease caused by the pathogenic fungus Mycosarcoma maydis, synonym Ustilago maydis. One of several cereal crop pathogens called smut, the fungus forms galls on all above-ground parts of corn species such as maize and teosinte. The infected corn is edible; in Mexico, it is considered a delicacy, called huitlacoche, often eaten as a filling in quesadillas and other tortilla-based dishes, as well as in soups.