Saccharomyces florentinus

Saccharomyces florentinus (now often classified under the genus Nakaseomyces) is a yeast-like fungus belonging to the kingdom Fungi and the phylum Ascomycota. While recognized for its role in industrial fermentation processes, in an agronomic context, it acts as an opportunistic microorganism contributing to the spoilage of fruit and berry crops.

The primary agricultural impact of Saccharomyces florentinus is the fermentation of sugars within damaged plant tissues. It typically affects grapes, stone fruits, and pomes, particularly when the fruit skin has been compromised by environmental stress, such as cracking after rainfall or damage caused by insect feeding.

Its biological cycle is characterized by cell budding and a robust ability to thrive in anaerobic environments rich in fermentable sugars. The pathogen persists in the environment within soil, crop residues, and the digestive tracts or body surfaces of various insect vectors, which facilitates its dispersal throughout the orchard or vineyard.

Optimal development conditions for this fungus include high relative humidity and moderate temperatures during the maturation stage of the fruit. When fruit integrity is compromised, the high concentration of soluble solids provides an ideal substrate for rapid yeast proliferation, leading to physiological changes in the fruit quality.

Control measures are primarily preventive and focus on mitigating the entry points for the pathogen. Effective strategies include:

• Integrated pest management (IPM) to minimize fruit damage by insects.
• Strategic irrigation management to prevent fruit cracking due to moisture fluctuations.
• Rapid and careful harvesting followed by strict temperature control during storage.
• Application of specialized fungicides to treat primary wounds or infections on the fruit surface.