Colletotrichum nicholsonii

The disease is caused by the fungal pathogen Colletotrichum nicholsonii, a member of the genus Colletotrichum. This fungus is a primary agent of anthracnose, which can severely impact the health and productivity of a wide range of agricultural and ornamental plants. It typically targets the aerial parts of the plant, causing necrosis and tissue degradation.

The fungus is characterized by its ability to survive on infected plant debris and in the soil for extended periods. Once conditions become favorable, Colletotrichum nicholsonii penetrates host tissues, often through natural openings or wounds, where it begins its lifecycle, drawing nutrients from the host and causing visible physiological damage.

Symptoms of the infection include localized lesions that may start as small spots and expand into larger, sunken, and necrotic areas. These spots often develop dark acervuli, which are the fruiting bodies of the fungus. Under high humidity, a distinctive mass of fungal spores, often appearing pinkish or white, can be observed on the lesion surfaces.

The spread of the pathogen is facilitated by environmental factors such as high humidity and temperatures between 20°C and 28°C. Water splashes from rainfall or overhead irrigation are the most common vectors for spore dissemination across fields or greenhouses. Poor airflow and high planting density exacerbate the spread, making early detection critical for management.

• Sanitation by removing and destroying crop residues to eliminate overwintering sites.
• Implementing strict crop rotation to reduce inoculum build-up in the soil.
• Application of appropriate systemic fungicides during high-risk weather conditions.
• Using certified disease-free seeds or planting material.
• Improving air circulation and managing humidity levels in protected cultivation.