Stenocarpella maydis, syn. Diplodia maydis, S. macrospora, syn. D. macrospora

Nature of damage

• Direct yield loss is caused by rotting of ears and kernels leading to reduced weight and nutritional content.
• Infection of kernels at the blister stage can result in reduced kernel size and grain filling.

Signs

• Characteristic development of irregular bleached areas on husks. These areas enlarge until the husks become completely dried, although the plant is still green.
• If husks are removed, ears appear chaffy and bleached, with a white, cottony growth between the kernels.
• Late in the season, many small, black pycnidia form on kernels and cob tissues.

Factors favoring development

• Stem borer injury in the ear often increases incidence of this disease.

Geographic distribution

• Stenocarpella ear rots are commonly found in hot, humid maize-growing areas.

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