Phaeosphaeria leaf spot

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.


  • 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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