Mature common smut galls on corn ear. In order to reduce infection points from insect injury, control corn borers as first tassels appear by application of insecticides when insect populations are high. Avoid injury of roots, stalks, and leaves during cultivation. Deep plow diseased corn stalks in the fall to bury surviving spores. Use resistant hybrids or varieties.
Dent corn is generally more resistant than sweet or popcorn.
In sweet corn, the larger, later-growing varieties usually are more resistant than the smaller, early varieties. The name loose smut describes the characteristic symptoms of the diseased heads as they extend from the boot in late spring. Loose smut reduces yield in proportion to the percentage of smutted heads in the field. To estimate the loss per acre, several hundred heads must be examined randomly in the field to determine the percent which are smutted. In seed fields this loss is continued into the next year's crop because some of the harvested grain will contain the loose smut fungus.