Plum Pocket

Conservation Status

IUCN Red List

not listed

NatureServe

NNA - Not applicable

Minnesota

not listed

Description

Plum Pocket is a fungus that infects all species of native plum but does not infect commercially cultivated plums from Europe and Asia. It occurs across the United States and in southern Ontario Canada. It is uncommon in Minnesota. It causes deformation and underdevelopment of fruit but is not fatal to the plant.

Plum pocket spores overwinter on twigs and buds of the host. The spores germinate in early spring and infect young developing fruit 6 to 8 weeks after the buds open. The infection first appears as small white blisters on the fruit. The vegetative part of the fungus (mycelium) grows between the cells of the fruit, causing the cells to expand and divide abnormally. The blisters enlarge as the fruit grows, and eventually envelop the entire fruit. Spore-bearing cells (asci) eventually break through the skin (epidermis) of the fruit.

The result is an enlarged, misshapen fruit with a grayish velvety coating. Seeds do not develop in infected fruits, and the hollow plums are called “pockets”. When the asci mature they release their spores which are spread by wind and splashed by rain to new plants and new parts of the same plant. These spores do not germinate until the following spring. Eventually the pockets turn brown or black and fall from the plant.

Similar Species

Habitat and Hosts

American plum, Canadian plum

Ecology

Season

Spring

Distribution

Sources

7, 24, 30, 77, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 7/10/2026).

Taphrina communis (Sadeb.) Giesenh. in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-06-19 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgy8b

Mycology Collections Portal (MyCoPortal) https://www.mycoportal.org/portal/collections/index.php). Accessed 7/10/2026.