Colletotrichum fioriniae

Taxonomic classification and nature of the pathogen. Colletotrichum fioriniae is a fungal pathogen belonging to the Ascomycota division, Glomerellales order, and Glomerellaceae family. As part of the Colletotrichum acutatum species complex, it is widely recognized for its aggressive pathogenic behavior. It is classified as a hemibiotroph, meaning it initially thrives on living host tissue but transitions to a saprotrophic phase once the host tissue starts to decay.

Host range and diseases. The fungus has a remarkably broad host range, impacting various fruit, berry, vegetable, and ornamental crops. It is a primary causal agent of anthracnose in apples, pears, strawberries, and tomatoes. The disease manifests as necrotic lesions on leaves, stems, and fruits, often progressing into bitter rot, which results in substantial economic losses both in the orchard and during post-harvest storage.

Biology and life cycle. The life cycle involves both asexual and sexual reproduction stages. In temperate climates, the pathogen overwinters as mycelium in infected plant debris, tree bark, or mummified fruits. During spring, under moist conditions, it produces conidia that are disseminated by wind and rain splashes. These spores germinate and form specialized infection structures called appressoria, which facilitate direct penetration into the plant epidermis.

Environmental conditions and impact. The development of the fungus is highly favored by high relative humidity (above 85%) and temperatures ranging from 20 to 28°C. Infection can occur throughout the growing season, though the fungus often remains latent in the fruit until ripening. The damage is severe, leading to fruit drop, reduced aesthetic quality, and rapid decay in cold storage facilities.

Protection and control measures. Effective management of Colletotrichum fioriniae requires an integrated approach to reduce inoculum pressure:

• Sanitation practices, including the removal and destruction of fallen leaves and mummified fruit that harbor the pathogen.
• Proper canopy management and pruning to improve air circulation and reduce humidity levels.
• Application of targeted fungicides, such as strobilurins and triazoles, during high-risk growth stages.
• Maintenance of optimal post-harvest storage conditions to inhibit fungal growth on harvested fruit.