Smuts are fungal diseases. They are most commonly seen on grasses, grains, and corn. Enlarged galls are soft and spongy when young but change to a dark, powdery mass as they age.
Corn smut can form on kernels, tassels, stalks, and leaves. Smut galls ripen and rupture, releasing spores that travel through the air to infect new plants and overwinter in the soil, awaiting future crops. To control corn smut, select resistant cultivars. Remove and burn galls before they break open, and follow a 4-year rotation.