Trichoderma fruit rot

Trichoderma fruit rot is a fungal disease caused by species within the Trichoderma genus. Although these fungi are often regarded as beneficial in soil microbiology, certain strains can act as opportunistic pathogens, causing severe decay in harvested fruits, particularly in high-moisture storage conditions.

The primary crop affected by this pathogen is the cranberry. The fungus typically invades the fruit through microscopic skin breaks or bruised areas occurring during harvest. Once the infection is established, the fungus utilizes the berry's moisture to rapidly colonize the internal tissue, leading to complete structural failure.

Key symptoms include the appearance of soft, water-soaked spots on the berry surface. As the infection progresses, a distinct mycelial mat develops, which eventually turns into a conspicuous emerald-green or olive-green layer of spores. The fruit loses its firm texture and develops a mushy consistency with an earthy odor characteristic of Trichoderma growth.

Disease outbreaks are heavily influenced by storage environment. Factors such as high humidity, poor ventilation, and temperature fluctuations in packing houses significantly accelerate rot development. Spores produced by the fungus are easily airborne or transmitted through contact, allowing the disease to spread rapidly from a single infected berry to the rest of the batch.

Management focuses on rigorous post-harvest hygiene and environmental control. Essential measures include:

• Rapid cooling of harvested berries to near-freezing temperatures.
• Thorough cleaning and disinfection of sorting lines and containers.
• Strict moisture control to prevent condensation on fruit surfaces.
• Culling and discarding any berries with mechanical injuries prior to storage.