The Effect of Downy Mildew on Corn

Leaves

• Corn plants affected by downy mildew develop mottling, chlorotic streaking and lesions on both surfaces of the leaves. White stripes develop on some leaves and eventually shred the leaves. Affected leaves become narrower and stand more erect.

Growth

• If downy mildew attacks corn seedlings less than 4 weeks old, the plants will become stunted and chlorotic. They will eventually die a premature death. Downy mildew also stunts the growth of mature plants and distorts the shapes of their reproductive organs. Seeds fail to form and tassels become bushy.

Tillers

• Corn plants affected by downy mildew produce abnormally high numbers of tillers. These tillers grow only a few inches, then wither and die. They appear as dense, dead clumps of vegetation.