Armillaria ostoyae

Taxobox
name = "Armillaria ostoyae"

---

regnum = Fungi
divisio = Basidiomycota
classis = Agaricomycetes
ordo = Agaricales
tribus = Tricholomataceae
genus = "Armillaria"
species = "A. ostoyae"
binomial = "Armillaria ostoyae"
binomial_authority = mycomorphbox
name = Armillaria ostoyae
whichGills = adnate
capShape = convex
hymeniumType=gills
stipeCharacter=ring
ecologicalType=saprotrophic
sporePrintColor=white
howEdible=edible

"Armillaria ostoyae" is a fungus commonly known as a Honey mushroom, and sometimes called Shoestring Rot.

This is the most common variant in the western U.S., of the group of species that all used to share the name "Armillaria mellea". "Armillaria ostoyae" is quite common on both hardwood and conifer wood in forests west of the Cascade crest. The mycelium attacks the sapwood and is able to travel great distances under the bark or between trees in the form of black rhizomorphs ("shoestrings").

The disease is of particular interest to forest managers, as the species is highly pathogenic to a number of commercial softwoods, notably Douglas-fir ("Pseudotsuga menziesii"), true firs ("Abies spp.") and Western Hemlock ("Tsuga heterophylla"). A commonly prescribed treatment is the clearcutting of an infected stand followed by planting with more resistant species such as Western redcedar ("thuja plicata") or deciduous seedlings. The removal of stumps (stumping) has been used to prevent contact between infected stumps and newer growth resulting in lower infection rates. However, it is unknown if the lower infection rates will persist as roots of young trees extend closer to the original inoculum from the preceding stand. The use of another fungus, "Hypholoma fasciculare" has been shown in early experiments to competitively exclude "Armillaria ostoyae" in both field and laboratory conditions, but further experimentation is required to establish the efficacy of this treatment.

A mushroom of this type in the Malheur National Forest in the Strawberry Mountains of eastern Oregon, U.S. was found to be the largest fungal colony in the world, spanning 8.9 km² (2,200 acres) of area. This organism is estimated to be 2,400 years old. The fungus was written about in the April 2003 issue of the "Canadian Journal of Forest Research". While an accurate estimate has not been made, the total mass of the colony may be as much as 605 tons. If this colony is considered a single organism, then it is the largest known organism in the world by area, and rivals the aspen grove "Pando" as the known organism with the highest living biomass.

In 1992, a relative of the Strawberry Mountains clone was discovered in southwest Washington state. It covers about 6 km² (1500 acres).

Another "humongous fungus" is a specimen of "Armillaria bulbosa" found at a site near Crystal Falls, Michigan covers 0.15 km² (37 acres), and was published in "Nature".cite journal |author=Smith ML, Bruhn JN, Anderson JB |title=The fungus "Armillaria bulbosa" is among the largest and oldest living organisms |journal=Nature |volume=356 |pages=428-431 |year=1992 |doi=10.1038/356428a0]

ee also

* Largest organism

References

External links

*Beale, Bob. 10 April 2003. [http://www.abc.net.au/science/news/enviro/EnviroRepublish_828525.htm Humungous fungus: world's largest organism?] at Environment & Nature News, ABC Online. Accessed January 2 2007.
* [http://news.bbc.co.uk/1/hi/sci/tech/869808.stm BBC News report about the largest Armillaria in the world]
* [http://botit.botany.wisc.edu/toms_fungi/apr2002.html Mycologist's site about giant Armillaria in Michigan's Upper Peninsula]
* [http://ext.nrs.wsu.edu/forestryext/foresthealth/notes/armillariarootrot.htm Armillaria Root Rot, Shoestring Root Rot, Honey Mushroom] Washington State University.
* [http://maps.wildrockies.org/ecosystem_defense/Science_Documents/Morrison_Mallet_1996.pdf Silvicultural management of armillaria root disease in western Canadian forests] Canadian Journal of Plant Pathology 18:194-199, 1996.
* [http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?_handler_=HandleInitialGet&journal=cjb&volume=82&calyLang=eng&articleFile=b04-078.pdf Early results from field trials using "Hypholoma fasciculare" to reduce "Armillaria ostoyae" root disease] Canadian Journal of Botany, Vol. 82, No. 7, pp. 962-969, 2004.