Side rot

Side rot, scientifically known as Phialophora malorum, is a significant post-harvest fungal disease that primarily affects pome fruits. This pathogen is particularly concerning for commercial storage operations because it can thrive in cold conditions, leading to unexpected decay of stored crops.

The disease primarily infects apple trees (Malus domestica) and pear trees (Pyrus communis). The fungus is a wound-invading pathogen, utilizing lenticels, insect punctures, or mechanical harvest injuries to penetrate the fruit surface and establish infection within the tissue.

The visible symptoms include the formation of small, firm, brown, or dark-colored lesions on the surface of the fruit, typically occurring on the sides. As the infection progresses, the lesions expand, and the underlying flesh becomes soft and discolored. In advanced stages, the fungus may produce small, dark, fruiting bodies on the surface.

The development of Phialophora malorum is facilitated by cool and moist environments. Unlike many other storage rots, this fungus is psychrophilic, meaning it can continue its growth even at standard cold storage temperatures (near 0°C). High humidity levels in warehouses further exacerbate the spread of spores from infected fruits to healthy ones.

Effective control measures include orchard sanitation to reduce inoculum levels and careful handling during harvesting to prevent wounding. In storage facilities, maintaining proper air circulation and utilizing effective sanitation practices for bins and crates are essential. Post-harvest fungicide treatments, where permitted, can also help mitigate the impact of this pathogen.