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Section 26.5.4: Northern Corn Leaf Blight

Various species

Time for concern: Whorl through tassel
Key characteristics: Long elliptical, grayish green or tan lesions ranging from 1 to 5 inches in length, develop on the lower leaves first, and then progress to younger tissue. Lesions often look “boat shaped.” This disease has increased in importance in the northeast.

Management Option Guideline
Scouting/thresholds

Fungicide sprays may be needed for fresh market sweet corn, hybrid seed production, and dent corn fields planted with susceptible hybrids. The following recommendations are from Ohio: The spray schedule should start when the first lesions appear on the leaf below the ear on 50% of the plants. Applications made at tasseling or silking (VT/R1) provide the most consistent results in terms of disease control and yield response.

Fresh Market Sweet Corn IPM Scouting Procedures

Resistant varieties Plant resistant varieties whenever possible. See Section 26.1 Recommended Varieties.
Crop rotation

Plant only in fields where sweet or field corn was not grown in the previous year.

Site selection Avoid fields with poor air drainage.
Postharvest Crop debris should be destroyed as soon as possible to remove this source of disease for other plantings and to initiate decomposition.
Seed selection/treatment
and Sanitation
These are not currently viable management options.
Pesticides Cornell Integrated Crop and Pest Management Guidelines for Commercial Vegetable Production