Cercospora leaf spot, otherwise known as frogeye leaf spot, is a disease of sweet pepper caused by the ascomycete fungus Cercospora capsici. Present in tropical and sub-tropical regions of the world, Cercospora leaf spot causes leaf lesions, which lead to defoliation and sun scald on fruit if the infection is severe enough.

Capsicum accuum (sweet and chili peppers) and C. frutescens (tobasco peppers) are susceptible hosts. This fungus is also known to remain viable from season to season, considered to survive on crop debris. There are no other known hosts at this time.

Symptoms appear on leaves, petioles, peduncles, and stems of affected plants. Fruit may not be infected but can be affected by diminished photosynthesis, often producing fewer yields and smaller fruits.

Small, round, water-soaked spots on leaves are the first symptoms of this disease. Eventually, these spots will develop into lesions that appear tan to white in color, with a darker border. As the disease progresses, more spots may appear around the original lesion and the central parts of the lesion become dry and cracked. Lesions that develop on the stem have the ability to become elongated, so they do not have the same circular properties of lesions that develop on the leaf. Stem lesions may girdle the plant completely.

This pathogen prefers hot, humid conditions. It is common in the southeastern states where night time temperatures remain relatively high (~70^oF).

• Bury crop debris
• Rotate crops
• Institute fungicide spray program at first signs of disease.
• Use resistant cultivars: some pepper cultivars are resistant to this fungus and may be beneficial if there is a history of high disease pressure

• Bury crop debris
• Rotate crops
• Use resistant cultivars: some pepper cultivars are resistant to this fungus and may be beneficial if there is a history of high disease pressure

• Remove affected leaves early (home gardens are usually small enough that this approach is feasible)
• Bury crop debris
• Rotate crops
• Use resistant cultivars: some pepper cultivars are resistant to this fungus and may be beneficial if there is a history of high disease pressure

• The NC State University Plant Disease and Insect Clinic provides diagnostics and control recommendations
• The Extension Plant Pathology Portal provides information on crop disease management
• The Southeastern US Vegetable Crop Handbook provides information on vegetable disease management
• The USDA Fungus-Host Distributions Database provides information about reported hosts for plant pathogenic fungi and oomycetes