Colletotrichum arboricola

Colletotrichum arboricola is a pathogenic fungus belonging to the genus Colletotrichum, widely recognized as a causal agent of anthracnose and severe leaf spot diseases in various woody plants. This pathogen is known for its ability to infect multiple plant tissues, including leaves, stems, and fruits, which significantly impairs the physiological health of the host.

This fungus primarily affects a broad range of agricultural crops and ornamental species, including citrus, tea plants, and various broad-leaved trees. The impact of Colletotrichum arboricola is particularly severe in high-density cultivation areas such as nurseries and commercial orchards where environmental conditions facilitate rapid disease transmission.

Symptoms typically manifest as necrotic lesions that vary in color from light brown to black. As the infection progresses, the centers of these lesions may develop small, cushion-like structures known as acervuli, which are responsible for the production of asexual spores (conidia). Heavy infestations often lead to premature abscission of leaves and dieback of young shoots, reducing overall plant vigor.

The development and spread of this disease are heavily favored by high relative humidity, prolonged periods of leaf wetness, and moderate temperatures. Rain splash, wind, and the movement of contaminated farm tools are primary vectors for dissemination. The fungus can survive the dormant season within infected plant debris or in perennial cankers on woody stems.

Effective management strategies combine cultural practices and chemical control. Growers should prioritize the removal and destruction of infected plant material to reduce the primary inoculum load. During the growing season, the application of systemic or contact fungicides, such as triazoles or copper-based formulations, is essential to prevent secondary infections and protect new growth.

• Regular pruning to improve air circulation.
• Sanitation by removing fallen leaves and debris.
• Use of resistant cultivars when available.
• Application of fungicides at the first sign of symptoms.