Corn Smut Control

Corn Smut Control & Treatment
 

CORN SMUT CONTROL

Corn smut is an extremely common disease of sweet, pop, and dent corn in Ohio and throughout the world. It is usually not economically important, although in some years yield losses in sweet corn may be as high as 20%. In Mexico, immature smut galls are consumed as an edible delicacy known as cuitlacoche, and sweet corn smut galls have become a high value crop for some growers in the NE United States who sell them to Mexican restaurants.
HOST PLANTS: Corn

SYMPTOMS: The corn plant may be infected at any time in the early stages of growth, but becomes less susceptible after formation of the ear. Above-ground parts may be infected, but it is more common to see smut galls on the ears, tassels, and nodes than on the leaves, internodes, and aerial roots (Figures 1 and 2). The smut gall is composed of a great mass of black, greasy, or powdery spores enclosed by a smooth white covering of corn tissue. The gall may be 4-5 inches in diameter. When leaves are infected, small pustules develop, usually on the midrib, causing some leaf distortion. After the spores mature, the outer covering becomes dry and brittle, breaks open, and the spores sift out. Greatest yield losses occur when the ear becomes infected or if smut galls form on the stalks immediately above the ears.

FAVORED ENVIRONMENT: Corn smut overwinters on garden debris and in the soil. It is carried by wind, rain and irrigation and does best in hot, dry weather. Spores may remain viable for 5 to 7 years. Wounds from various injuries, including cultivation and abrasion from blowing soil, provide points for the fungus to enter the plant.

CORN SMUT CONTROL: Choose resistant varieties when available. In backyard gardens, collecting and destroying galls before the dark fungal spores are released is suggested. This will limit the number of available fungal spores and help break the disease-cycle. Reduce infection points by avoiding injury of roots, stalks, and leaves during cultivation. Prevent damage from insects, such as corn borers, with organic insecticides. Apply sulfur or copper fungicides weekly when the disease is first noticed and continue applications as long as disease conditions are favorable. Remove and destroy all plant debris after harvest and practice crop rotation the following year. Do not compost infected plant parts.

Products for Corn Smut Control