''Naohidemyces vaccinii'' is a

plant pathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

that affects members of the '' Vaccinium'' and '' Tsuga'' genera, causing leaf

rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH ...

lingonberries ''Vaccinium vitis-idaea'', the lingonberry, partridgeberry, mountain cranberry or cowberry, is a small evergreen shrub in the heath family Ericaceae, that bears edible fruit. It is native to boreal forest and Arctic tundra throughout the Norther ...

blueberries Blueberries are a widely distributed and widespread group of perennial flowering plants with blue or purple berries. They are classified in the section ''Cyanococcus'' within the genus ''Vaccinium''. ''Vaccinium'' also includes cranberries, bi ...

, and

cranberries Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus ''Oxycoccus'' of the genus ''Vaccinium''. In Britain, cranberry may refer to the native species ''Vaccinium oxycoccos'', while in North America, cranberry m ...

, and early needle cast on hemlocks. ''Naohidemyces vaccinii'' is found on the ''Vaccinium'' genus in Canada, the United States (AK, ME, NH), the United Kingdom, Europe, Russia, China, Korea, and Japan, and on hemlock in AK, ID, WA in the United States, BC in Canada, and Japan.

Taxonomy

''Naohidemyces vaccinii'' is a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

rust fungi with a number of different synonyms, including '' Pucciniastrum vaccinii'' and ''Pucciniastrum myrtilli'', but was moved to the ''Naohidemyces'' genus due to its dome-shaped covering over the aecia. ''N. vaccinii'' is now thought to be the western form of the fungi, and ''Thekopsora minima'' as the eastern form.

Pathology

''Naohidemyces vaccinii'' causes leaf rust on the leaves of the ''Vaccinium'' host, and chlorosis and early abscission on both ''Vaccinium'' and ''Tsuga'', to which neither is fatal but can be a drain on fruit yield.

Life cycle

''Naohidemyces vaccinia'' is wind-borne, and initially forms yellow-orange urediniospores in pustulates on the underside of ''Vaccinium'' leaves in midsummer, which reinfect ''Vaccinium'' leaves, building up inoculum for reinfection. This is followed by flat telia crusts in late summer for overwintering, although rarely on lingonberries. Teliospores germinate from telia in spring, from which basidia form, releasing basidiospores to ''Tsuga'' species. Once alighting on ''Tsuga'' needles in the spring, pyncia are formed. Finally in early summer, yellow-orange aeciospores form in shallow conical aecia on the underside of the needles in two rows following the length of the needle.

Disease impact

Leaf rust is most common on cultivated ''Vaccinium'' and relatively rare in wild populations. It is a relatively benign disease, and has little direct impact on crops, but has become an epidemic in rare occasions, particularly to cultivated blueberries.

Controls

Fungicides have been shown to be effective against ''N. vaccinii'', but not all are registered for blueberries, cranberries, or lingonberries. Applications depend on climate and species, as ''Vaccinium'' that keep their leaves throughout the year may need to be treated far earlier than the first sign of leafing out. Removing ''Tsuga'' or other wild, evergreen ''Vaccinium'' hosts within 0.5 km of crops can be beneficial in breaking the sporulation cycle.

References

External links

{{Taxonbar, from=Q6964527 Teliomycotina Fungal plant pathogens and diseases Taxa named by Johannes Baptista von Albertini Taxa named by Lewis David de Schweinitz Fungi described in 1805 Fungi of Asia Fungi of Europe Fungi of North America