Common root sponge

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This article was based on formal or substantive deficiencies in the quality assurance biology in the section "Mycology" entered for improvement. This is done in order to bring the quality of the biology articles to an acceptable level. Please help improve this article! Articles that are not significantly improved can be deleted if necessary.

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Reason: The article text takes on the species in a broader sense and therefore needs to be revised - the Technical University of Munich provided an overview ( Memento from August 30, 2014 in the Internet Archive ). - Ak ccm ( discussion ) 02:46, Feb. 16, 2014 (CET)
Common root sponge
Heterobasidion annosum - Lindsey.jpg

Common root sponge ( Heterobasidion annosum )

Class : Agaricomycetes
Subclass : insecure position (incertae sedis)
Order : Russulales (Russulales)
Family : Mountain Porling Relatives (Bondarzewiaceae)
Genre : Root sponges ( heterobasidion )
Type : Common root sponge
Scientific name
Heterobasidion annosum
( Fr  .: Fr.) Bref. s. st.

The common root sponge ( Heterobasidion annosum ) is a type of fungus from the family of mountain porlings . As forest pest he caused in the affected spruces a red stain . This core rot is very important economically. At least vegetatively, i.e. without additional appearance of its fruiting bodies, the root sponge can be described as extremely common in all (including former) forest areas.


Half resupinate form
Resupinate form

Macroscopic features

The fruiting bodies of the root sponge can be designed as flat hats, semi-resupinate or resupinate (lying on the substrate). The hats have a sharp edge (not rounded) and are often irregularly grown together. They reach a width of 5 to 15 centimeters and a length of 1 to 8 centimeters (measured from the substrate to the edge of the hat); in the middle they become one to two centimeters thick. The color ranges from gray to red to dark brown; Incremental edges are white.

The wrinkled top is finely felted, but later balded; it can also be zoned. It consists of a thin black crust that can be easily dented. When the fruit body is dried, it appears as a dark, shiny line; In contrast, the Trama is whitish to wood-colored and has a corky, tough consistency, and when dry it has a woody consistency. It turns dark reddish brown with Melzer's reagent .

On the underside are the tubes, whose year-by-year layering is rather difficult to see. The small, round pores are creamy white to ocher yellow in color. The spore powder is white.

Microscopic features

The generative hyphae are hyaline . They have buckleless septa (partitions). The skeletal hyphae are also hyaline and mostly unbranched. They discolor in Melzer's reagent or Lugol wine-red (dextrinoid) and their cell walls with cotton blue violet (cyanophil).

The basidia are hyaline, club-shaped and have no basal buckle; they each form four spores. These are also hyaline, broadly ellipsoidal to spherical and measure 4–7 × 3–5 micrometers. They have a fine black surface and a thin outer wall, which are slightly discolored in Melzer's reagent (weakly amyloid).

Where no fruiting bodies are formed, occurrences of this fungus on fresh, moist wood can be microscopically demonstrated on the numerous conidia that are formed on the inflated hyphae ends.

Species delimitation

The root sponge is usually difficult to find generatively due to its mostly small fruit bodies, which are inconspicuous on the upper side and protrude deep on the trunk or on superficial roots, although it must be described as extremely common vegetatively. Pale brownish specimens can be confused with the row tramete ( Antrodia serialis ), which, however, has no hat crust and whose mycelium produces a cubic brown rot in the wood.


The root sponge can be found in practically all types of forest. Due to its "preference" for spruce, it is particularly common in spruce forests. Occasionally, the fungus can also be found in parks, gardens and similar areas. However, it is rare on trees that stand alone or in smaller groups.

The root sponge lives parasitically on the base of the trunk, on roots or stumps of various coniferous and deciduous trees. Its mycelium causes all phases of wood rot one after the other. The spores are usually more than 90 percent capable of germination. They germinate much better in damp and cool conditions than in dry conditions.

The fruiting bodies are perennial and can therefore be found all year round. The growth and the sporulation set in in the south of Germany shortly after the beginning of spring and persist throughout the year. This process is largely independent of temperature and is only interrupted for a short time by extremely cold or dry conditions. The fruiting bodies and spores can even withstand sudden freezing to −18 degrees Celsius in a moist environment. Spore production is cyclical, with the maximum at midnight and the minimum at noon.

Harmful effect

Red rot in spruce wood
Red rot in the lower trunk of a storm-thrown spruce

Especially in young spruce monocultures, the root sponge can cause major damage that can run into the millions. In natural mixed forests, however, it does not pose a serious threat. For this reason, the fungus was viewed by forest managers as a pest and by nature conservationists as a "beneficial". As a result, the root sponge has repeatedly been discussed in relation to its role in the forest ecosystem .


Trees are usually infected through the roots, either through the basidiospores washed into the ground or through root contact with neighboring trees that are already infected. The basidiospores can also very easily be a wooden body not protected by bark, e.g. B. over the fresh cut surfaces of the stumps of felled trees, infested. Mostly stumps with a diameter of about ten centimeters are affected, which corresponds to a wood age of 15 to 20 years.

An infection of other trees, which is very considerably accelerated compared to root growth, occurs through peeling .

First afforestation on formerly agriculturally used, limed areas is particularly at risk, with a high pH value (> 5.5) favoring the disease. In addition, soil containing carbonate, densely packed, shallow, alternately moist and sandy soils increase the risk of infestation.

Clinical picture

In spruce trees, the mycelium penetrates the trunk after infection and grows upwards. It can rise up to half a meter in a year and reach a height of sixteen meters. The fungus causes a special white rot in the heartwood , which is also known as red rot due to its reddish-brown color . The wood is decomposed in such a way that - in contrast to a cubic brown rot - it retains a longitudinal fiber consistency.

In pines, the mycelium does not spread upwards in the trunk, but is sealed off by the formation of resin, similar to an infestation by the frilled mother hen . Instead, it decomposes the roots, which still causes the tree to die. Since this phenomenon occurs especially on formerly agricultural land, it is also used as arable death called.


An effective treatment of infested trees is not possible. Only preventive measures can be taken to prevent new infections. To do this, saturated urea solution (37 percent) can be applied to freshly cut surfaces, which prevents the fungus from penetrating. A promotion or inoculation of tree stumps with antagonistic fungi such as Phlebia gigantea ( giant bark fungus ) or Trichoderma viride is also possible. Because of the competition, the root sponge cannot settle. With the help of P. gigantea , the infection rate can be reduced by 80 percent. The sodium nitrite that was used in the past is harmful to the environment and is therefore no longer used today.


The root sponge is particularly widespread in the Holarctic , where it occurs mainly temperate to boreal . But it can also occur meridionally. The mushroom can also be found in Australia and New Zealand as well as in India, Pakistan and Central America.

The root sponge is widespread in the Holarctic and is apparently only absent in China and Japan, where H. insulare can instead be found in the coastal areas. In North America, the fungus is common in the USA, along with Alaska, and Canada; in Asia it occurs in the northern part of the Middle East ( Asia Minor , Iran) and in the Caucasus, as well as in Siberia , Central Asia and the Far East .

In Europe, the root sponge is widespread from the coast of the Mediterranean and the Atlantic to the eastern border of the continent, the Urals; to the north the area extends to the Hebrides and the north of Fennoscandinavia . In the latter region, however, the fungus is quite rare. It is common throughout Central Europe and especially in the coniferous forest areas.

In Germany, the root sponge is often and practically completely represented everywhere, including on the islands. In the Alps, the fungus can sometimes reach the tree line.

Related species

European species
  • Fir root sponge ( Heterobasidion abietinum ) Niemelä & Korhonen 1998
  • Pine root sponge ( Heterobasidion annosum ) ( Fr. ) Bref. 1888
  • Spruce root sponge ( Heterobasidion parviporum ) Niemelä & Korhonen 1998
More types



Individual evidence

  1. Ewald Gerhardt: FSVO manual mushrooms . BLV, Munich 2006, ISBN 3-8354-0053-3 . P. 459
  2. German Josef Krieglsteiner (Ed.): Die Großpilze Baden-Württemberg. Volume 1: General Part. Stand mushrooms: jelly, bark, prick and pore mushrooms. Ulmer, Stuttgart 2000, ISBN 3-8001-3528-0 , p. 535.
  3. a b c d e f Information for forest owners. Root sponge. Endangerment - Symptoms - Control. (PDF; 523 kB) Ministry of Infrastructure and Agriculture Brandenburg
  4. a b Information for forest owners. Root sponge as a pathogen in arable and dump afforestation. Biological basics - symptom analysis - defense measures.  ( Page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Ministry of Infrastructure and Agriculture Brandenburg (for all sales)@1@ 2Template: Toter Link /  
  5. The fresh rhizome is an open door for the root sponge.
  6. One of the most common parasitic fungi is the root sponge Heterobasidion annosum (Fr.) Bref. ( Memento of the original from January 10, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot /
  7. The fresh rhizome is an open door for the root sponge. (for the entire paragraph)

Web links

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