Smuts affect grasses, notably including cereal crops such as maize. They initially attack the plant's reproductive system, forming galls which darken and burst, releasing fungal spores which infect other plants nearby.
A smut infestation is controlled by removing and destroying the infected plants. In Agriculture, this process is known as destruction of the initial inoculum.
Sugarcane smut or culmicolous smut is caused by the fungus Ustilago scitaminea. The smut 'whip' is a curved black structure which emerges from the leaf whorl. Sugarcane smut causes significant losses to the economic value of a sugarcane crop. Sugarcane smut which has recently been found in the Eastern Seaboard Areas of Australia, which is one of the worlds highest yielding sugar areas.
Corn smut, (Ustilago maydis), which infects maize, is a delicacy in Mexico, and Brazil, originally enjoyed by the Aztecs. It enlarges the ear of corn and fills it with sooty spores. Corn smut causes millions of dollars in crop damage every year. However, the immature galls of corn smut remain a popular delicacy and is deliberately cultivated in some areas as huitlacoche.
- Covered smut Tilletia tritici (syn. T. caries) and T. laevis (syn. T. foetida)