Bacterial rot of apples

The causative agent of this disease is the bacterium Pseudomonas melophthora. It is a specific phytopathogen known to cause bacterial decay in apple fruits, particularly affecting them during the ripening stage and post-harvest storage.

The disease primarily targets apple cultivars. The bacterium enters the fruit tissues through natural openings like lenticels, or more commonly, through mechanical wounds and injury sites caused by orchard pests such as the codling moth.

Symptoms of the infection include the development of water-soaked spots on the surface that eventually turn brown. Internally, the flesh softens and degrades, often accompanied by a distinct unpleasant odor. In many cases, the decay proceeds internally while the skin remains seemingly intact for some time.

Development and spread are favored by high humidity and moderate temperatures. The pathogen utilizes water films on the fruit surface to move and infect healthy tissues, while insect vectors facilitate the transfer of bacteria within the canopy and during the harvest process.

Effective prevention and control strategies involve integrated pest management to reduce fruit wounding, careful handling during harvest to minimize bruising, and the maintenance of strictly controlled atmospheric conditions in storage facilities to slow down bacterial proliferation.