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White Pines - Jelly, Scurvy, and Rust

 Most cultivated currants are of European origin.  There are also North American species.  The fruit of currants is used for jams, jellies, pies, and fresh and frozen fruit.  The fruit is high in vitamin C and was used in the past by Europeans to prevent scurvy.  The fruit, especially that of black currants, is also high in antioxidants and anthocyanins.  Native Americans and Europeans used the fruit as a medicinal treatment for various internal infections.  The fruit is also purported to help prevent liver cancer.  Because of these uses and the interest in traditional and heritage plants, there is a growing market for currants and gooseberries.

Photo Above: Aecia of white pine blister rust (Cronartium ribicola) on the trunk of a pine tree.
Photo by:  H.J. Larsen, Bugwood.org

While this is good for the growers of small fruit nursery stock, it causes a problem for the white pine.  WPBR is considered the most destructive disease of five-needle pines in North America.  The disease is of Asian origin.  It was thought that Swiss stone pine was the original host of the fungus.  In 1705, Eastern white pine seedlings from North America were exported to England, and then distributed throughout Eastern Europe.  This brought the Eastern white pine in contact with the disease.  By the mid-1800s there were outbreaks of WPBR in Eastern Europe.  In the late 1800s to early 1900s, U.S. and Canadian nurserymen from both the east and west coasts imported low-cost white pine seedlings from Europe for forestry planting.  These imports brought the rust to North America.  Over time the disease has spread inland. 

The blister rust cycle begins in the fall when pine needles are infected by spores from the alternate host, Ribes spp.  The spores germinate and enter the needles through the stomata and grow down the needle to the branches and the phloem cells.  This causes a swollen canker.  It takes about three years after a tree is infected to produce visible symptoms.  In the spring, spores are produced on the surface of the tree and these are carried long distances by wind to the Ribes spp. host.  Several weeks after a Ribes spp. host is infected, light yellow spots appear on the upper surface of the leaves.  Orange spores develop on the underside of the leaf and these spores will continue to reinfect other Ribes spp. until fall.  The fall spores infect the white pine, completing the cycle. 

One early attempt to control WPBR was the destruction of infected white pine, but the latent time from infection to visual symptoms failed to control the problem.  In 1912, the United States enacted the Plant Quarantine Act (7 USC 151 et seq.) in an attempt to prevent further introduction and spread of the disease.  Later quarantines prohibited the importation of five-needle pines into the U.S.; authorized the eradication of Ribes spp. in pine forests and in cultivations; and prohibited movement of Ribes spp. west of the Mississippi River.  Eradication of wild Ribes spp. was found to be expensive and impractical.

To control and eradicate WPBR in Michigan, the White Pine Blister Rust, Act 313 of 1929, was enacted.  It declared the rust “to be a dangerous forest pest in all its stages.”  The cultivated black currant was declared a public nuisance and “planting, possessing, growing, propagating, selling or offering for sale plants, roots, or cuttings” was prohibited.  The Act also provided for designating counties in the state where white pine is common as WPBR control areas and the remaining counties as fruiting currant and gooseberry production areas for growing Ribes spp.  Permits are required to plant Ribes spp. in the WPBR control area and for white pine to be planted in the Ribes spp. control area.  Planting of black currants is still prohibited state-wide except under permit.

Permits may be granted for the planting of WPBR-resistant varieties of currant and gooseberry plants in Michigan.  The Michigan Department of Agriculture and Rural Development issues the permits.  Permits can be obtained by contacting Mike Bryan, Nursery and Export Specialist at bryanm@michigan.gov or (800) 292-3939, indicating the varieties, the quantity, and address where they will be planted. 

Permission will be granted only to those varieties that have been shown to be highly resistant to WPBR through scientific research.

The following varieties of Ribes spp. are considered acceptable at this time based on their WPBR resistance rating:

  •      Gooseberries: Achilles, Captivator, Columbus, Downing, Glenton Green, Golda, Hinnomaen kiltaenen green (Hinnomaki yellow), Howards Lancer, Jahns Prairie, Jeanne, Josselyn, Oregon, Pixwell, Poorman,   Sabine, Whitesmith
  •      Black currant-Gooseberry hybrids: Josta (a.k.a. Jostaberry)
  •      Black currant: Consort (Prince Consort), Crusader, Coronet, Crandall, 'Doch Siberyachki (Daughter of
  •      Siberia), Kosmioleskaja, Lowes Auslese, Minaj smyriou, Pilot Alexander Mamkin, Polar, Risager, Titania, Willoughby
  •      Red & white currant cultivars: Rondom, White Imperial, White Currant 1301

These varieties were identified as WPBR resistant in consultation with USDA researchers in Corvallis, Oregon, as listed on their websites at:

http://www.ars.usda.gov/SP2UserFiles/Place/53581500/catalogs/ribrustimmu...
http://ars.usda.gov/SP2UserFiles/Place/53581500/catalogs/ribrustresist.html

Michigan was once known as the king of white pine.  From 1850 to 1900, Michigan delivered more board feet of white pine to the mills than did any other state.  In 1955, Eastern white pine became Michigan’s state tree.  Michigan has approximately 36 million acres of land and before European settlement in the state, ten million acres of it was pine.  WPBR has devastated the white pine forests in many parts of North America.  WPBR can still be found in cultivated and wild plantings of white pine in northern Michigan.  Currant jellies are delicious, so enjoy them and protect our white pine resource by selecting a rust resistant variety.



References:

MSU Extension Service, Michigan State University.  Growing Currants & Gooseberries.  E-856, SF-8 July 1977.
Michigan Department of Agriculture and Rural Development.  White Pine Blister Rust Control Areas & Fruiting Currant and Gooseberry Control Areas.  Sept. 2011.
Maloy, Otis C.  White Pine Blister Rust.  APSnet.  2008.
Landowner’s Guide.  Dry Mesic Conifers.
Government Printing Office.  The Plant Quarantine Act, August 20, 1912, As Amended March 4, 1913 and March 4, 1917.
Government Printing Office.  White Pine Blister Rust Quarantine.  Quarantine No. 63 Revision Regulations.  1937.
MSU Extension Bulletin, Michigan State University.  Unusual Fruit Plants for Gardens in the North Central Region.   E-2747 March 2001.
Michigan Department of Agriculture and Rural Development.  White Pine Blister Rust Resistant Currant & Gooseberry Varieties.  Update February 8, 2012.
State of Michigan.  White Pine Blister Rust Act 313 of 1929.  1929 and 2003.
NCGR-Corvallis Ribes Catalog.  White Pine Blister Rust (Cronartium ribicola) Immune Genotypes.  March 1, 2012.
NCGR-Corvallis Ribes Catalog.  White Pine Blister Rust (Cronartium ribicola) Resistant Genotypes.  March 1, 2012.
Boyce, John Shaw.  Forest Pathology.  3rd Edition.  McGraw-Hill Book Company, Inc., New York.  1961.