Cercospora leaf spot of pepper

Cercospora capsici is a fungal pathogen responsible for causing Cercospora leaf spot, a prevalent and damaging disease in pepper crops globally. This fungus thrives under warm and humid conditions, posing a significant threat to greenhouse and open-field production systems alike.

The disease primarily targets peppers (Capsicum species), including bell, chili, and ornamental varieties. All aerial parts of the plant, especially the leaves, are susceptible to infection. When left unchecked, the disease can cause severe defoliation, significantly reducing the plant's photosynthetic capacity and fruit development.

Diagnostic symptoms include the formation of small, circular to angular spots on leaves. As these lesions mature, they develop grey or white centers with distinctive dark brown or purplish margins. In cases of severe infestation, the spots coalesce, causing the leaf tissue to necrotic, yellow, and eventually drop prematurely.

The spread of the fungus is facilitated by high humidity, frequent rain, or overhead irrigation, which splashes spores onto healthy foliage. The pathogen survives between growing seasons in infected plant debris left in the soil or on contaminated seed surfaces. Optimal temperatures for disease development range between 20°C and 30°C.

Effective management requires a proactive strategy that combines sanitation, cultural practices, and chemical control. Growers must focus on removing debris, ensuring proper plant spacing for airflow, and implementing early-season monitoring to detect the first signs of the infection before it becomes widespread.

• Rotate crops with non-solanaceous plants to break the disease cycle.
• Use certified disease-free seeds or seedlings.
• Maintain proper greenhouse ventilation to minimize leaf moisture duration.
• Apply preventative fungicides based on copper or other systemic active ingredients.
• Promptly remove and dispose of infected plant tissues to reduce the inoculum load.