Cronartium ribicola
Encyclopedia
Cronartium ribicola is a species
of rust fungi
in the family Cronartiaceae
that causes the disease white pine blister rust.
Like many other rusts, C. ribicola is heteroecious
, meaning it requires two host species to complete its lifecycle that includes five spore stages. The aecial hosts are white pines (Pinus subgenus Strobus
, family Pinaceae
) and the telial hosts include wild and introduced currants
and gooseberries
(Ribes, family Grossulariaceae
), and two genera of the Orobanchaceae
, Pedicularis and Castilleja
. Species of both telial and aecial hosts have varying levels of resistance or immunity to infection. This rust is believed to be native to Asia
or Europe
and was subsequently introduced to North America. Some European and Asian white pines (e.g. Macedonian Pine
, Swiss Pine
, Blue Pine
) are mostly resistant to the disease, having co-evolved with the pathogen.
It was accidentally introduced into North America about 1900, where it is an invasive species
causing serious damage to the American white pines, which have little genetic resistance. Mortality is particularly heavy in Western White Pine
, Sugar Pine
, Limber Pine
and Whitebark Pine
. Efforts are under way to select and breed the rare resistant individuals of these species; resistance breeding is concentrated at the United States Forest Service
Dorena Genetic Resource Center in Oregon
.
Some limited silvicultural
control of the disease is possible. If bark blisters are found on branches over 10-15 cm from the bole, those branches may be pruned off, which will stop the spread of the disease to the rest of that tree. If the main trunk is affected then no control is possible, and the tree will die once the infection girdles the tree. Infected trees are often identified by "flagging", when all the needles on a branch turn brown and die. Infections often occur on low branches close to the ground on young trees, so pruning of white pine can also be effective in multiple ways, as it improves the quality of timber by creating more knot-free timber, and reduces the likelihood of infection from the blister rust to a small extent. Another form of control practiced in some areas is to diligently remove Ribes
plants from any area near white pines. Because the infection moves from currant plants, to pines, and back again, it cannot continue to exist without its alternate host. Although effective in theory, removal of currants is rarely successful in practice, as they readily re-grow from small pieces of root left in the soil, and the seeds are very widely spread in birds' droppings. According to the Southwest Oregon Forest Insect and Disease Service Center, white pine blister rust attacks all five needle pines. "Damage [to plants] includes mortality, topkill, branch dieback, and predisposition to attack by other agents, including bark beetle
s" http://www.fs.fed.us/r6/rogue/swofidsc/pineblister/pineblister.html.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of rust fungi
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
in the family Cronartiaceae
Cronartiaceae
Cronartiaceae are a family of rust fungi in the order Uredinales.They are heteroecious rusts with two alternating hosts, typically a pine and a flowering plant, and up to five spore stages. Many of the species are plant diseases of major economic importance, causing significant damage and heavy...
that causes the disease white pine blister rust.
Like many other rusts, C. ribicola is heteroecious
Heteroecious
A heteroecious parasite is one that requires at least two hosts. The primary host is the host in which the parasite spends its adult life; the other is the secondary host. Both the primary host and an unrelated alternate host are required for the parasite to complete its life cycle...
, meaning it requires two host species to complete its lifecycle that includes five spore stages. The aecial hosts are white pines (Pinus subgenus Strobus
Pinus classification
There are three main subgenera of Pinus, the subgenus Strobus , the subgenus Ducampopinus , and the subgenus Pinus...
, family Pinaceae
Pinaceae
Pinaceae are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae are supported as monophyletic by its protein-type sieve...
) and the telial hosts include wild and introduced currants
Currant
Currant may refer to:Plants:* Ribes, genus of berry plants, e.g. blackcurrant, redcurrant* Zante currant, dried Black Corinth grapes; smaller than raisins* Currant tomato, Solanum pimpinellifolium, small tomato species...
and gooseberries
Gooseberry
The gooseberry or ; Ribes uva-crispa, syn. R. grossularia) is a species of Ribes, native to Europe, northwestern Africa and southwestern Asia...
(Ribes, family Grossulariaceae
Ribes
Ribes is a genus of about 150 species of flowering plants native throughout the temperate regions of the Northern Hemisphere. It is usually treated as the only genus in the family Grossulariaceae. Seven subgenera are recognized....
), and two genera of the Orobanchaceae
Orobanchaceae
Orobanchaceae, the broomrape family, is a family of flowering plants of the order Lamiales, with about 90 genera and more than 2000 species. Many of these genera were formerly included in the family Scrophulariaceae sensu lato...
, Pedicularis and Castilleja
Castilleja
Castilleja, commonly known as Indian paintbrush or Prairie-fire, is a genus of about 200 species of annual and perennial herbaceous plants native to the west of the Americas from Alaska south to the Andes, northern Asia, and one species as far west as the Kola Peninsula in Siberia...
. Species of both telial and aecial hosts have varying levels of resistance or immunity to infection. This rust is believed to be native to Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
or Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and was subsequently introduced to North America. Some European and Asian white pines (e.g. Macedonian Pine
Macedonian Pine
Pinus peuce is a species of pine native to the mountains of Macedonia, Bulgaria, Albania, Montenegro, Kosovo, the extreme southwest of Serbia, and the extreme north of Greece, growing typically at 1,000-2,200 m altitude. It often reaches the alpine tree line in this area...
, Swiss Pine
Swiss Pine
The Swiss Pine or Arolla Pine, Pinus cembra, is a species of pine tree that occurs in the Alps and Carpathian Mountains of central Europe, in Poland , Switzerland, France, Italy, Austria, Germany, Slovenia, Slovakia, Ukraine and Romania. It typically grows at to altitude. It often reaches the...
, Blue Pine
Blue Pine
Pinus wallichiana is a pine native to the Himalaya, Karakoram and Hindu Kush mountains, from eastern Afghanistan east across northern Pakistan and India to Yunnan in southwest China. It grows at high altitudes in mountain valleys at altitudes of 1800–4300 m , and is a tree from 30–50 m in height...
) are mostly resistant to the disease, having co-evolved with the pathogen.
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
causing serious damage to the American white pines, which have little genetic resistance. Mortality is particularly heavy in Western White Pine
Western White Pine
Western White Pine, Pinus monticola in the family Pinaceae, is a species of pine that occurs in the mountains of the western United States and Canada, specifically the Sierra Nevada, the Cascade Range, the Coast Range, and the northern Rocky Mountains. The tree extends down to sea level in many...
, Sugar Pine
Sugar Pine
Pinus lambertiana, commonly known as the sugar pine or sugar cone pine, is the tallest and most massive pine, with the longest cones of any conifer...
, Limber Pine
Limber Pine
The Limber Pine, Pinus flexilis, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Southwestern White Pine and Rocky Mountain White Pine...
and Whitebark Pine
Whitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...
. Efforts are under way to select and breed the rare resistant individuals of these species; resistance breeding is concentrated at the United States Forest Service
United States Forest Service
The United States Forest Service is an agency of the United States Department of Agriculture that administers the nation's 155 national forests and 20 national grasslands, which encompass...
Dorena Genetic Resource Center in Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
.
Some limited silvicultural
Silviculture
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...
control of the disease is possible. If bark blisters are found on branches over 10-15 cm from the bole, those branches may be pruned off, which will stop the spread of the disease to the rest of that tree. If the main trunk is affected then no control is possible, and the tree will die once the infection girdles the tree. Infected trees are often identified by "flagging", when all the needles on a branch turn brown and die. Infections often occur on low branches close to the ground on young trees, so pruning of white pine can also be effective in multiple ways, as it improves the quality of timber by creating more knot-free timber, and reduces the likelihood of infection from the blister rust to a small extent. Another form of control practiced in some areas is to diligently remove Ribes
Ribes
Ribes is a genus of about 150 species of flowering plants native throughout the temperate regions of the Northern Hemisphere. It is usually treated as the only genus in the family Grossulariaceae. Seven subgenera are recognized....
plants from any area near white pines. Because the infection moves from currant plants, to pines, and back again, it cannot continue to exist without its alternate host. Although effective in theory, removal of currants is rarely successful in practice, as they readily re-grow from small pieces of root left in the soil, and the seeds are very widely spread in birds' droppings. According to the Southwest Oregon Forest Insect and Disease Service Center, white pine blister rust attacks all five needle pines. "Damage [to plants] includes mortality, topkill, branch dieback, and predisposition to attack by other agents, including bark beetle
Bark beetle
A bark beetle is one of approximately 220 genera with 6,000 species of beetles in the subfamily Scolytinae. Traditionally, this was considered a distinct family Scolytidae, but now it is understood that bark beetles are in fact very specialized members of the "true weevil" family...
s" http://www.fs.fed.us/r6/rogue/swofidsc/pineblister/pineblister.html.
External links
- Don't Move Firewood - Gallery of Pests: White Pine Blister Rust
- forestpathology.org
- Dorena Genetic Resource Center
- The Sugar Pine Foundation
- The Whitebark Pine Ecosystem Foundation
- Species Profile- White Pine Blister Rust (Cronartium ribicola), National Invasive Species Information Center, United States National Agricultural LibraryUnited States National Agricultural LibraryThe United States National Agricultural Library is one of the world's largest agricultural research libraries, and serves as a National Library of the United States and as the library of the United States Department of Agriculture...
. Lists general information and resources for White Pine Blister Rust.