Gray Leaf Spot
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Gray leaf spot (Cercospora zeae-maydis) tends to be most active in the period just before tasseling and beyond. Early symptoms include yellow lesions with a faint halo. Older lesions have a distinct rectangular shape; lesions tend to be narrow and between 3 and 4 inches in length. Lesion color changes from brown to tan-gray as spore production begins. The causal agent survives in crop debris and its effect can be severe in poorly rotated fields. High humidity is required for infection and spread of disease.
Gray leaf spot.
(Photo: Paul Vincelli, University of Kentucky)
Management:
- Crop rotation, resistant varieties, incorporation of corn residues, and fungicides.
