Common Smut

Disease Facts

Common smut caused by the fungus Ustilago maydis is a common disease of field corn found in New York State.  

Common smut may infect all above ground parts of the plant but causes the greatest economic losses when the ear becomes infected or if smut galls form on the stalks immediately above the ears.

Infection is favored by dry conditions as seen during a drought as well as mechanical injury due to hail.

Higher levels of common smut are observed in fields with soils with high N levels or after heavy applications of manure.

Management Strategies

Management strategies include the use of resistant hybrids and avoiding mechanical injury of plants. See the Handy Bt Trait Table updated for 2023 for U.S. Corn Production from the University of Michigan for recommendations.

Proper maintenance of soil fertility can also play a role in managing this disease.

Symptoms

White, soft galls may form on all above ground parts of the plant including ears, tassels and leaves.

As the galls age, the interior darkens turning into masses of dark green to black powdery spores.

a disease corn plant

Common smut on corn after deer damage

a stalk of corn with a healthy cob and disease damage

Common corn smut