Cercospora leaf spot of pepper

Cercospora leaf spot, caused by the fungus Passalora capsicicola, is a destructive disease affecting various solanaceous crops, most notably sweet peppers. The pathogen disrupts the normal physiological functions of the plant, often leading to reduced yield and poor fruit development if left unchecked.

The primary symptom is the appearance of small, circular or irregular spots on the foliage. These lesions usually have a gray-to-tan center surrounded by a dark brown or reddish-brown halo. As the infection progresses, these spots enlarge, causing the leaves to turn yellow (chlorosis) and eventually abscise prematurely.

High humidity and temperatures ranging from 20°C to 30°C create optimal conditions for fungal sporulation and infection. The pathogen survives between growing seasons in infected plant debris left in the field or in the soil. Moisture, such as heavy rain, dew, or overhead irrigation, plays a critical role in spreading the spores to healthy tissue.

The severity of the disease lies in the loss of photosynthetic leaf area. When the plant loses a significant portion of its foliage, it cannot produce enough energy to support fruit set and growth. This results in undersized peppers, sunscald on fruits exposed to direct sunlight, and significantly reduced marketability of the harvest.

Effective management requires a multi-faceted approach involving cultural practices and chemical interventions. Sanitation is paramount, including the removal and destruction of crop residues. Chemical control should be implemented early using registered fungicides to prevent the spread of the pathogen.

• Crop rotation with non-solanaceous plants.
• Installation of drip irrigation to keep foliage dry.
• Use of certified, disease-free seed stock.
• Timely application of preventive copper or triazole-based fungicides.