If you grow corn, you may occasionally notice swollen, lumpy growths forming on the ears. Many people worry when they see this and wonder whether the corn is ruined. In most cases, the crop is still safe. These unusual growths are known as corn smut, a naturally occurring fungus that affects corn plants without making them toxic or chemically contaminated.Corn smut is caused by Ustilago maydis, which transforms smooth kernels into soft, pale gray or silvery lumps. As it matures, the surface darkens and eventually turns black. The fungus can also appear on stalks or tassels.

Warm, moist conditions and small plant injuries from wind or insects allow spores to enter and develop. Its presence does not mean the corn was poorly grown or unsafe.When harvested at the right stage—while the growths are firm, moist, and odorless—corn smut is considered safe to eat when properly cooked. It should be avoided only if it is dry, crumbly, or has a strong unpleasant smell. Eating it is entirely optional, and discarding it is perfectly acceptable if it feels unappealing.