Diplodia Leaf Streak of Corn
Published: 11/30/2023
Diplodia leaf streak is caused by the fungus Stenocarpella macrospora. Symptoms are typically first observed in the mid-lower canopy as small, round, dark brown or brown lesions on leaves. These small lesions may have concentric rings visible in the center. As disease progresses, the lesions will expand and can result in long streaks (several inches to over 12 inches long) on leaves and/or form long elliptical-shaped lesions that can resemble lesions of northern corn leaf blight. Large areas of leaves can be blighted by the disease. Within mature lesions, small, dark, round fungal structures (pycnidia) can be observed.
Diplodia leaf streak lesions on corn leaf.
Kiersten Wise
Leaf lesions on corn caused by Stenocarpella macrospora,
Kiersten Wise
The fungus overwinters on residue and has been reported to infect seed. Infection can occur at any growth stage. Spores are dispersed by wind and splashing water. Disease development is favored by high humidity and moderate temperatures (64-81°F).
The fungus that causes Diplodia leaf streak can also cause Diplodia ear rot. The relationship between the presence of Diplodia leaf streak and the occurrence of Diplodia ear rot is poorly understood, but each disease can occur independently.
Diplodia leaf streak has not been reported to cause yield loss. While management is not currently needed, rotating away from corn and reducing residue can limit the amount of fungus that overwinters each year. Hybrid susceptibility to Diplodia leaf streak is not well known, and there are currently no foliar fungicides specifically labeled for this disease.
Developed by Nolan Anderson Texas A&M University; and Kiersten Wise, University of Kentucky.
Diplodia leaf streak lesions. Image by Kiersten Wise.
Early Diplodia leaf streak lesions. Image by Kiersten Wise.
Diplodia leaf streak lesions. Image by Kiersten Wise.
Diplodia leaf streak lesions with visible pycnidia. Image by Kiersten Wise.
Gallery images courtesy Kiersten Wise.
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