Corn Disease Management in Ohio

Bulletin 802

Viral Diseases

Figure 22. Maize dwarf mosaic is a persistent problem in southern Ohio where johnsongrass is a weed problem. The virus that causes this disease overwinters in johnsongrass and is transmitted by aphids to the new corn crop in spring. Maize chlorotic dwarf, very similar to Maize dwarf mosaic, is another viral disease, but it is transmitted from johnsongrass to corn by leafhoppers.

The two most important viral diseases of corn in Ohio are maize dwarf mosaic (Figure 22) and maize chlorotic dwarf. The diseases are controlled by use of disease-tolerant hybrids. Virus-tolerant hybrids are those that maintain an acceptable yield although they are infected with the virus. Both diseases are transmitted by insect vectors, and the viruses overwinter in johnsongrass. These diseases rarely cause a problem in northern Ohio. However, since johnsongrass occurs primarily in southern Ohio, tolerant hybrids are highly recommended wherever johnsongrass is a problem.

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Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension

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