Corn Leaf Diseases: Eyespot

Excerpt from Agronomy Guide for Field Crops (Chapter 3)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Incidence
2. Appearance
3. Disease Cycle
4. Management Strategies
5. Updates on Corn Leaf Diseases: Eyespot
6. Related links...

Incidence

Although eyespot normally causes minor losses in corn, the disease has been increasing in Ontario with the shift to leaving corn residue in the field.

Appearance

The disease produces characteristic round or oval spots (1-4 mm (1/16-1/8 in.)) with a tan/brown centre and a brown or purple margin. A translucent yellow halo forms around the margin, and when held to the sun, the lesions resemble an eye. Leaf blighting may occur when these lesions join, killing large portions of leaf tissue. The disease may be confused with non-infectious physiological leaf spots or insect damage.

Plate 27. Eyespot causes round or oval leaf spots with a tan/brown centre, a brown or purple margin, and a translucent yellow halo when held up to the sun.

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Disease Cycle

The disease is more prevalent under continuous corn and reduced tillage systems, since the fungus overwinters in corn residue. Disease development is favoured by cool, wet conditions.

Management Strategies

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Updates on Corn Leaf Diseases: Eyespot

• Field Crop Protection Guide - Publication 812
  • Corn: Eye Spot

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Related links...

• Diseases
• Corn

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