Yarrowia

Yarrowia is a genus of yeast-like fungi that, while valuable in industrial biotechnology, acts as a significant post-harvest pathogen in agricultural systems. The most common species, Yarrowia lipolytica, is known to cause rapid decomposition and decay of various horticultural products during storage.

The causative agent belongs to the phylum Ascomycota. It is a necrotrophic pathogen that utilizes extracellular enzymes, particularly lipases and proteases, to degrade plant tissues. This type of decay is primarily categorized as post-harvest soft rot, which exploits the biochemical composition of susceptible fruits and vegetables.

The host range includes pome fruits like apples and pears, stone fruits, and solanaceous crops such as tomatoes. The infection typically occurs after harvest, following mechanical injuries, skin micro-tears, or damage caused by insect pests, which provide the entry point for fungal colonization.

Symptoms initially appear as localized, softened, and sunken areas on the skin of the fruit. As the infection progresses, the tissues become necrotic and may be covered with a characteristic creamy, yellowish biofilm of fungal colonies. An off-odor is frequently observed due to the rapid enzymatic breakdown of lipids within the infected produce.

Disease development is heavily influenced by high relative humidity and temperatures exceeding the optimal cold storage range. The economic impact is high, as the fungus spreads through contact, causing rapid rot in storage crates and significantly reducing the shelf life and marketability of agricultural products.

• Maintaining optimal hygiene in packing houses and storage units.
• Careful handling to minimize bruising or puncturing of fruits.
• Rapid cooling of produce post-harvest to slow microbial growth.
• Continuous monitoring of temperature and humidity in storage facilities.
• Strict exclusion of infected produce from storage batches.