Metschnikowia pulcherrima

Metschnikowia pulcherrima is a yeast species belonging to the Ascomycota phylum and the Metschnikowiaceae family. In the context of agriculture, it is recognized as a complex organism capable of causing postharvest fruit decay while simultaneously serving as a highly effective biological control agent against other harmful fungi.

This yeast primarily affects fruit crops such as grapes, apples, pears, and stone fruits. When acting as a pathogen, it colonizes the surface of the fruit, exploiting minor wounds or cuticle ruptures. This infection leads to tissue softening, discoloration, and overall deterioration of the fruit quality.

The biology of M. pulcherrima revolves around its metabolic efficiency in utilizing sugars and its ability to rapidly compete for space on host surfaces. Its lifecycle includes an asexual phase characterized by budding and a sexual phase producing characteristic needle-shaped ascospores, which ensure its survival in diverse environments.

Environmental conditions favoring its development include moderate temperatures (20–25°C) and high humidity levels. The spread of the fungus is often mediated by wind, water splashes, and insect vectors that transport the cells into orchards and vineyards, where they quickly settle on ripe or overripe fruits.

Control measures primarily focus on integrated crop management. To limit its pathogenic effects, producers emphasize:

• Proper handling to prevent mechanical injury during harvest.
• Sanitation in storage facilities to reduce inoculum pressure.
• Optimized humidity levels in cold storage rooms.