Phaeosphaeria maydis

Nature of damage

• Loss of photosynthetic leaf area due to lesions results in less photosynthate production for grain filling.
• Under severe disease pressure, sugars may be diverted from the stalks for grain filling resulting in crop lodging.

Signs

• Lesions appear as small pale green areas, which later become bleached and finally necrotic, surrounded by dark brown margins.
• Spots on leaves are round to slightly elongated.

Factors favoring development

• High humidity (> 70%).
• Relatively low night temperatures.

Geographic distribution

• This disease is found in Brazil, Colombia, Ecuador, northern India, eastern and southern Africa, the USA, and Mexico, where Exserohilum turcicum is also prevalent.

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