Colletotrichum crassipes

The causative agent Colletotrichum crassipes is a fungal pathogen belonging to the Ascomycota phylum. This fungus is a primary agent responsible for causing anthracnose diseases in a broad range of botanical hosts. It functions primarily as a necrotrophic pathogen, colonizing host tissues and producing various enzymes that facilitate the breakdown of plant cell walls, leading to localized necrosis.

Host susceptibility to Colletotrichum crassipes includes numerous ornamental species, particularly orchids, and various tropical fruits like coffee and guava. The pathogen exhibits high versatility, attacking leaves, twigs, and fruits. Its presence is often detected in both commercial plantations and greenhouse environments, where microclimatic conditions are highly favorable for fungal proliferation.

Diagnostic symptoms typically manifest as sunken, necrotic spots or lesions that can vary in size and shape. As the disease advances, these lesions often turn dark brown or black and may merge, resulting in large blighted areas. In the center of the lesions, small, raised structures known as acervuli appear, which produce masses of conidia often visible as slimy, pinkish, or white spore droplets.

Disease development is highly dependent on environmental factors, specifically high relative humidity and temperatures ranging from 20 to 30 degrees Celsius. The dispersal of spores occurs mainly through water splashes during rain or overhead irrigation, as well as by wind currents. The fungus persists in infected plant debris, soil, or symptomless host tissues, allowing it to remain viable between growing seasons.

Management of Colletotrichum crassipes requires an integrated approach to disease prevention. Key practices include:

• Removal and destruction of all infected plant material.
• Improvement of airflow and canopy management to reduce leaf wetness duration.
• Use of disease-free planting material.
• Application of protective and systemic fungicides during high-risk periods.
• Implementation of crop rotation where feasible to break the disease cycle.