Phoma fruit rot of apple

The fungus Ectophoma pomi is the causal agent of a specific type of fruit rot affecting pome fruits. This pathogen is primarily recognized for its ability to cause lesions on apple fruit, which often develop late in the growing season or emerge during the storage phase.

Apples are the most common host for Ectophoma pomi, though the disease has been documented on other pome fruits. The fungus behaves as a necrotrophic pathogen, colonizing host tissues and causing the breakdown of fruit pulp, which renders the produce unmarketable.

Symptoms initially appear as small, circular, light-colored spots on the skin of the fruit. As the infection progresses, these lesions turn dark brown or black and become sunken into the surface of the apple. A diagnostic feature is the appearance of small, black, pin-head-sized fruiting bodies known as pycnidia, which emerge within the necrotic area.

Environmental conditions play a crucial role in disease dissemination. High humidity, heavy rainfall, and moderate temperatures favor the production and dispersal of conidia. In storage, the disease spreads rapidly if fruits are wounded or if ambient humidity levels are not properly managed, allowing the fungus to colonize neighboring healthy fruit.

Integrated management is essential for controlling this fungal disease. Orchard sanitation, including the removal of mummified fruit and infected branches, is the first line of defense. Growers should apply protective fungicides during the growing season and ensure that harvested fruit is stored in cold, well-ventilated environments to inhibit fungal growth and spread.