Sphacelotheca reiliana is a plant disease that affects corn crops. It is commonly known as corn smut or huitlacoche, and its synonyms include maize smut, corn fungus, and Ustilago maydis. This fungal disease is often a problem for farmers, as it can cause significant damage to their crops and lead to reduced yields. Corn smut is characterized by the formation of large, grayish-black masses on the ears of corn, which are filled with spores. Despite its negative effect on crop productivity, some people consider huitlacoche a delicacy, as it is used in traditional Mexican cuisine and has a distinctive, earthy flavor.