Answer: Corn smut is caused by the fungus Ustilago zeae. The fungal spores can remain in the soil 2 or 3 years, and spores can be wind-blown long distances. Infection occurs in the seedling stage at soil temperatures of 70F to 86F degrees.
The best ways to control this problem is to stop planting corn for 3 or 4 years in lightly infested fields, or try planting resistant varieties. Another method to "outwit" the fungus is to plant your corn seed shallowly to promote rapid germination, or try pre-germinating your seed by placing between two damp paper towels. If you can keep the seedbed moist the first 4 weeks after planting, you may be able to discourage fungal growth.
Some studies have shown that a "living mulch" of white clover sown between the corn rows can help suppress the corn smut fungus. However, note that you may need to water the planting more often, as the clover will compete with the corn for water.
Q&A Library Searching Tips