Also known as Cercospora leaf spot
Cercospora zeae-maydis, C. sorghi varmaydis

Nature of damage

• Can result in severe leaf senescence following flowering and in poor grain fill.
• Loss of photosynthetic leaf area results in reduced yield.
• Yield losses up to 70% due to gray leaf spot have been reported.

Signs

• Lesions begin as small, regular, elongated brown-gray necrotic spots growing parallel to the veins.
• Occasionally, lesions may reach 3.0 x 0.3 cm.
• Lesions usually develop on the lower leaves, gradually spreading upwards on the plant during the season.

Factors favoring development

• Minimum tillage practices have been associated with an increased incidence of GLS.
• Development is favored by extended periods of leaf wetness and cloudy conditions

Geographic distribution

• May occur in subtropical and temperate, humid areas.
• The disease is of concern in South America and eastern and southern Africa.