Leucostoma

(Nitschke) Hohn., 1917

Leucostoma is a of ascomycete in the Cytosporaceae ( Diaporthales). in this genus are that cause canker , primarily affecting woody . The genus produces both sexual (perithecia) and (pycnidia) fruiting bodies, with the asexual stage formerly classified under the name Leucocytospora. Leucostoma species are distributed across temperate regions of North America, Europe, and Asia.

Habitat

Associated with , particularly branches of Salix (willow) and Populus (poplar) . Found in temperate forest and orchard environments.

Distribution

Canada, USA (Colorado, Idaho, Iowa, Montana, New Mexico, New York, North Dakota, Pennsylvania, South Dakota, Virginia, Washington, Wyoming), Republic of Georgia, Iran, Kazakhstan, Kyrgyzstan, Pakistan, Austria, Bulgaria, Denmark, Finland, Germany, Hungary, Italy, Latvia, Montenegro, Netherlands, Poland, Romania, Russia, Serbia, Slovakia, Spain, Sweden, Switzerland, Ukraine, and UK.

Host Associations

Salix sp. - Primary ; found on branches
Populus sp. - Secondary ; rarely found

Ecological Role

causing canker on woody . The stage (Leucocytospora) produces in pycnidia that disperse to infect new tissue.

Human Relevance

Economic impact as a of cultivated trees. Leucostoma cincta has caused significant losses in apple orchards, particularly affecting McIntosh . Canker expansion is greater during spring and fall than summer, with bark cracking, peeling, and leaf death as progress.

Similar Taxa

LeucocytosporaLeucocytospora is the (anamorph) stage of Leucostoma; and colony characteristics ( to buff initially, turning ) are used to distinguish this connection

More Details

Nomenclature note

The name Leucostoma has also been used for a genus in (Animalia) and appears as a subspecific epithet in other (e.g., Agkistrodon piscivorus leucostoma, Cydia leucostoma). This record refers specifically to the fungal genus Leucostoma ().

Disease symptoms

Initial canker appear as orange discolored areas on bark, frequently associated with pruning wounds or winter injury. At later stages, bark cracks and peels, with leaves to cankers dying. Perithecia of Leucostoma and pycnidia of Leucocytospora may both be present on infected tissue, though pycnidia often predominate.