Plum pockets

Plum pockets, caused by the fungus Taphrina pruni, is a common and destructive disease affecting stone fruit trees. This fungal infection results in the abnormal development of fruit, rendering them inedible and causing significant harvest losses for orchardists.

The primary hosts of this pathogen are trees within the Prunus genus, most notably cultivated plums, damsons, and wild plums. The fungus infects the developing flower buds and ovaries early in the season, preventing normal fruit maturity and pit formation.

Infected fruits become visibly distorted, elongated, and puffed up, resembling hollow pouches or pockets. As the disease progresses, the surface of these malformed fruits develops a powdery, whitish coating of fungal spores. Eventually, the fruits shrivel, turn a dark brown or black color, and drop prematurely from the branches.

The development and spread of Taphrina pruni are heavily dependent on climatic conditions. The fungus thrives during cool, wet spring weather, particularly when high humidity persists during the blossoming period. These conditions are ideal for the release and germination of fungal spores, which can easily infect neighboring trees via wind and rain splash.

Effective management requires a proactive approach centered on sanitation and chemical intervention. Growers should prune and destroy all affected fruits and twigs immediately upon discovery. Applying copper-based fungicides or other appropriate treatments during the late dormant stage, just before bud break, is the most effective way to prevent infection in the upcoming season.