Forest & Grassland Health

Viburnum Leaf & Stem Rust

Puccinia linkii Klotzsch (=Micropuccina linkii (Klotzsch) Arthur & H.S. Jacks.)

Host(s) in Alaska:

Highbush-cranberry (Viburnum edule)

Habitat(s): foliage, petioles, berries, and stems

Photos

Click on image for larger version.

Leaf spots caused by Puccinia Linkii.

Leaf spots on highbush-cranberry caused by Puccinia linkii.

Fruit infection

Puccinia linkii infection of a single berry.

Stem and heavy foliar infection

Heavy petiole and foliar infection beneath a perennial stem infection.

New stem infection

A new stem infection on a current-year shoot.

 

       

Fruit infection by Puccinia linkii

Highbush-cranberry berry infection. Photo credit: Bruce Welkovich.

Bud and shoot infection by Puccinia linkii.

Highbush-cranberry bud and shoot infection. Photo credit: Bruce Welkovich.

New shoot infection by Puccinia linkii.

Highbush-cranberry shoot infection. Photo credit: Bruce Welkovich.

 

Teliospores of Puccinia linkii.

Teliospores of Puccinia linkii obtained from a perennial stem infection.

 

 

Current Status & Distribution in Alaska (2020 Update)

Elevated damage from this disease has been observed in 2020. Increased disease incidence and severity is likely related to cool, wet conditions during the growing season. Leaf rust of highbush cranberry (Viburnum edule) occurs in Alaska and elsewhere in North America. In 2014, this disease was observed causing stem rust near Juneau, Alaska, marking the first time stem damage had been attributed to this fungus (first report available here). Since that time, the disease has been recorded at numerous locations throughout Alaska (Fairbanks, Anchorage, Soldotna, Willow, Susitna North, Skagway, and Juneau). The distribution of stem infections in Alaska is not well known, but stem infections are thought to be most common in the coastal rainforest. iNaturalist has been a helpful way to track this disease in Alaska.

Symptoms, Biology & Impacts

Infections begin as smooth magenta spots on leaves, petioles, fruits, and stems that darken as spores (teliospores) develop. Foliar infections tend to be most extensive close to perennial stem infections. As spores are produced, leaf spots appear dark brown and fuzzy or rough. Disease intensifies during the growing season, with infections becoming larger and sometimes coalescing when disease is severe. Stem infections are usually lethal to affected stems and give rise to more intensive infections on nearby susceptible leaves, petioles, and fruits. Stem infections can be observed any time of year as perennial swellings, while new infections are initiated after leaf flush.

Survey Method

Damage is observed through ground surveys. Observations from the public have helped us to document the fungus throughout the state, especially using the iNaturalist app. Recording the presence or absence of stem infections can improve our distribution information for this form of the disease.

Links to Resources & Publications

Anderson, J. P. 1952. The Uredinales of Alaska and adjacent parts of Canada. Iowa State Coll. J. Sci. 26:507-526.

Cash, E. K. 1953. A checklist of Alaskan fungi. Plant Dis. Rep. Suppl. 219:1.

Daust, K. 2013. Impact of the rust Puccinia linkii on highbush cranberry, Viburnum edule, near Smithers, British Columbia. Can. Field Nat. 127:270. Available here.

Mulvey, R. and S. Hambleton. 2015. Stem Rust of Highbush-Cranberry (Viburnum edule) Caused by Puccinia linkii near Juneau, Alaska. American Phytopathological Society Disease Note. Available here.

USDA. 1960. Agric. Handb. (U. S. Dep. Agric., Sci. Educ. Adm.) 165:1.

 

Content prepared by Robin Mulvey, Forest Health Protection, robin.mulvey@usda.gov. 

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