Causal Agent:
Fungus (Exerohilum tursicum syn Hemninthosporium tursicum)
| Characteristic Symptoms: | |
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Long, gray-green and elliptical or cigar-shaped lesions develop first on older lower leaves. |
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Pale gray to tan lesions will be formed as the disease progresses. |
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Husks can be infected with the disease but not on ears. |
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Lesions on resistant hybrids have a yellow margin. |
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NCLB pathogen overwinters on leaves, husks, and other plant parts in debris. |
| Conditions for Disease Development: | |
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Moderate temperatures, heavy dews, and frequent showers are favorable for the disease. High losses will occur with infection before silking. |
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In wet weather, black spores are produced on the lesions that are wind-blown over long distances. Secondary spread is common within and between fields. |
| Management and Control: | |
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Use resistant varieties, if available.
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Crop rotate with non-host to reduce corn residues and disease inoculum. |
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Apply fungicides such as pyraclostrobin+dimetomorph (e.g. Cabrio®), azoxystrobin (e.g. Amistar®) or propiconazole (e.g. Bumper®, Tranzole ®). |
References
https://www.pioneer.com/home/site/us/agronomy/crop-management/corn-insec...
The CIMMYT Maize Program. 2003. Maize Diseases: A Guide for Field Identification. 4th edition. Mexico, D.F.: International Maize and Wheat Improvement Center (CIMMYT).
Wise, K. 2015. Fungicide efficacy for control of corn diseases. Purdue Extension Publication BP-160-W. Purdue University, West Lafayette, Indiana.
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