Maize dwarf mosaic virus

Maize dwarf mosaic virus (MDMV) is a plant pathogenic virus of the family Potyviridae.

Symptoms
Symptoms vary with the corn hybrid and the stage of development of the plant at the time of infection. Early infection results in chlorotic spots or flecks that elongate in young leaves in the whorl. Flecks merge into chlorotic streaks along the leaves. These streaks form mosaic or mottled patterns and may turn to a general yellowing as the growing season progresses. Later, plants may have blotches or streaks of red that generally appear after periods of cool 16°C (60°F) night temperatures. Infected plants are predisposed to root rot and may be barren.

Control
Grow hybrids tolerant or resistant to MDMV. Destroy johnsongrass and other grass hosts, including volunteer corn in areas where corn is to be planted. Best control occurs when all growers in a community area cooperate in eradicating hosts. Plant early, since early planted corn will escape damage because aphid populations do not build up until the plants are past the seedling stage.