Geotrichum candidum

Geotrichum candidum is a filamentous fungus belonging to the kingdom Fungi and the genus Geotrichum. It is a well-known opportunistic plant pathogen that frequently causes post-harvest decay in various fruit and vegetable crops, leading to significant economic losses in agricultural supply chains.

The primary disease associated with this fungus is sour rot. It is commonly identified on tomatoes, citrus fruits, carrots, and other succulents. Infected tissues exhibit a soft, watery consistency and are covered with a velvety white or cream-colored fungal growth that emits a distinctive acidic odor.

The biology of the pathogen relies on the production of arthrospores, which are readily dispersed via wind, water splashes, or insect vectors. The fungus typically enters plant tissues through wounds, surface abrasions, or cracks caused by environmental stress or secondary infections by other microorganisms.

Optimal conditions for the development of Geotrichum candidum include high relative humidity (above 85%) and warm temperatures ranging from +20°C to +25°C. The pathogen thrives in storage environments with poor aeration, where it can rapidly spread from infected items to healthy produce through direct contact or spore dissemination.

Control strategies for sour rot are primarily preventative, focusing on maintaining the integrity of the harvested produce:

• Careful handling during harvest to minimize skin injuries.
• Strict sorting procedures to remove damaged items before storage.
• Sanitation of packing houses and cold storage containers.
• Managing storage humidity and temperature to prevent moisture condensation on produce surfaces.