In the spring, insects transmit the virus to young corn plants. Corn planted at the appropriate time, and not too late in the season, is often damaged less by viruses. There is no chemical control available. They are caused by various species of fungi, including Fusarium , Diplodia , Pythium and Macrophomina . Some of these disease-causing organisms enter through the roots and move up into the stalk, while others enter the stalk directly at the nodes.
Insect damage can increase infection by wounding the plant and allowing fungi to enter.
Do not exceed recommended plant densities. Keep soil fertility balanced based on soil tests. All insect controls should be carefully followed as described in HGIC 2205, Insect Pests of Sweet Corn . This disease is caused by the fungus Helminthosporium maydis . Symptoms occur as leaf spots or cob rots and are fairly easy to recognize on plants.