Colletotrichum fioriniae

Colletotrichum fioriniae is a significant fungal pathogen within the Colletotrichum acutatum species complex. It is primarily known as the causal agent of anthracnose, a disease that affects a wide range of horticultural and agricultural crops worldwide. This pathogen is highly efficient at infecting host tissues, leading to significant yield reductions and post-harvest decay.

The host range of Colletotrichum fioriniae is quite extensive, including key crops such as strawberries, blueberries, cranberries, and various fruit trees. The fungus can colonize almost any part of the plant, including flowers, leaves, and stems, but it is most notorious for causing severe fruit rot that develops both in the field and after the produce is harvested and stored.

Symptoms of the infection typically appear as small, water-soaked spots on the surface of the fruit, which gradually expand into sunken, necrotic lesions. Under humid conditions, these lesions become covered with masses of spores, often appearing as distinct pink or orange spore pustules. Foliar symptoms include irregular brown spots with dark margins, which may result in chlorosis and premature defoliation.

The spread of the disease is heavily dictated by environmental factors. High relative humidity and warm temperatures, typically ranging from 20°C to 28°C, facilitate the germination of spores and the development of the fungal mycelium. Rainfall and overhead irrigation are primary drivers for spore dispersal across the field, splashing the pathogen onto healthy plant tissues.

Effective management of Colletotrichum fioriniae requires a multi-faceted strategy:

• Sanitation, including the removal and destruction of infected plant debris.
• Improving canopy ventilation to reduce humidity levels around fruit clusters.
• Strategic application of registered fungicides during critical flowering and ripening stages.
• Sourcing pathogen-free nursery stock to prevent introducing the fungus to new fields.
• Regular field scouting to detect and isolate early infection outbreaks.