Mushroom house (Serpula lacrymans)Systematics:
- Department: Basidiomycota (Basidiomycetes)
- Subdivision: Agaricomycotina (Agaricomycetes)
- Class: Agaricomycetes (Agaricomycetes)
- Subclass: Agaricomycetidae (Agaricomycetes)
- Order: Boletales
- Family: Serpulaceae (Serpulaceae)
- Genus: Serpula (Serpula)
- Species: Serpula lacrymans (Mushroom house)
This fungus belongs to the category of harmful fungi that destroy trees.
Its other names:
house sponge (Merulius destruens Pers)
nostril destroyer (Merulius vasitator Tode)
It settles on felled dead trees, and is especially dangerous when breeding in various buildings. Once settled in a tree, it can easily and quickly destroy wooden parts.
The mushroom house has a well-developed ability (inherent in all mushrooms to varying degrees) to form a powerful mycelium even in completely unsuitable conditions for fruiting. These conditions include stagnant stale air, high humidity, and lack of light. In the presence of these factors, the fungus develops very abundantly and quickly in the form of a sterile form and actively conducts destructive activity.
As a rule, this fungus spreads in basements and cellars, where it is humid and stuffy, on the bottom of the floorboards, at the base of the beams. It feels especially good if the floor is directly on wet soil.
At the beginning of the development of the fungus, small white dots appear on the tree, which over time merge into slimy spots or woolly delicate deposits, then a plexus similar to a silvery cobweb appears. Gradually, it spreads more and more over the surface of the tree, thickens, acquires a leafy structure, a silky sheen and an ash-gray color.
Along the edges of the mushroom, thin threads are formed, passing over spurs, with the help of which the mushroom, as it were, crawls in search of food through small cracks and holes in the walls. Thus, he moves from one area of the house to another. Sometimes such destructive work can lead to the destruction of the entire house and its fall.
A mushroom house can sometimes act in conjunction with other representatives of fungi, for example, Polyporus vaporarius, Polyporus destructor, and others. Most often, the mushroom house affects conifers, but it can also damage deciduous ones, for example, oak.
Effect on wood
During his research, R. Gartig found that the fungus secretes special enzymes that are capable of dissolving organic compounds of wood at a great distance from the fungus. As a result, the tree turns into a form that the mushroom is able to assimilate. In addition, these enzymes are capable of dissolving the ash constituents in the cell membranes upon their direct contact with the hyphae. As a result of all these processes, the tree is destroyed.
Gradually the wood turns brown, transforms into dust, and if in a fresh state it is soft enough, then as a result of the action of the fungus, it dries up, becomes brittle and fragile. Especially easily wood fungus destroys a floor covered with oil paint, because in this case the underside of the floor is completely protected from light and protected from drying out.
The fact that such a mushroom has appeared on the wood can be understood by the black spots appearing on the upper surface, and if the wood is covered with glue paint, then yellowish fluffy areas are formed on it, located separately from each other.
If you knock on wood contaminated with a tree fungus, you get a dull sound, and when pressed, it breaks easily. The affected tree absorbs water very actively, it becomes too hygroscopic, so moisture from the bottom can pass even to very distant parts of the house. In addition, the mycelium of the fungus itself has the ability to easily conduct moisture and transfer it to dry wood, so even in the driest rooms it can become very damp and it will be impossible to live in them.
In addition, there is another unpleasant moment: the fruiting bodies of the fungus, during decomposition and decay, emit a characteristic and very unpleasant odor, which is also harmful to health.
According to Polek and Geppert's research, woody mushrooms can contain 48 to 68% water.
If the mycelium comes out through cracks or cracks into fresh air and light, then the fruiting bodies of the fungus begin to form. They are lamellar, plate-shaped, wide, can reach a size of up to a meter, have a leathery fleshy consistency. At the beginning of development, the fruit bodies are white, then they become reddish-yellow, and at the end they are rusty-brown. From above they have writhing worm-like folds on which spores are located, and from below they have a fibrous velvety structure with white swollen edges. The edges of the fruit bodies secrete transparent drops of liquid, which later becomes cloudy, acquires a milky color (therefore, this mushroom is called crying). The spores are elliptical, small (0.011 mm long and 0.006 mm wide), brown or rusty-brown in color. Spore germination is possible only in the presence of substances with an alkaline reaction.It can be potassium carbonate, salts, or ammonia itself. These substances provoke the swelling of the spore membrane. Germination is also facilitated by urine, ash, coke and other substances that contain or are involved in the formation of substances with an alkaline reaction.
To prevent the appearance of a house mushroom, R. Gartig recommends using the following preventive measures:
- After completing repairs in buildings infected with woody fungus, workers must thoroughly clean and rinse all their tools before using them again. You should also wash your clothes and boots thoroughly.
- if the old wood has obvious traces of fungus infection, then it cannot be used for new buildings. Old destroyed wood extracted during repairs must be burned as soon as possible, and fresh wood should not be stored next to damaged wood.
- new buildings must be protected from contamination by builders, and toilets must be equipped in such a way that contamination of new buildings does not occur indirectly.
- Use coarse washed sand or crushed bricks as a cushion under the floor. Various raw masses cannot be used, especially ash, coke, and other materials rich in humus should be avoided.
- before starting construction, the tree must be dried as thoroughly as possible.
- the newly built house should dry out properly, and only after that the floors can be painted with oil paint.
- it is necessary to build in such a way that the floors do not adhere too tightly to the walls.
- it is important to properly organize air draft in the lower rooms under the floor.
- you need to carefully observe cleanliness, and make sure that impurities and water do not fall under the floor. This is especially true for bathrooms and laundries.
In order to destroy the mushroom house that has already appeared, a lot of means are used, but none of them can be called radical. Fairly good results were obtained by a German forester G.L. Gartig, who in the 19th century impregnated pieces of wood with carbolineum or creosote.
Professor Sorokin gives his recommendations for covering wood with ordinary tar, and some other researchers call petroleum among the effective means.
If the fungus has not yet spread very much, then a good result can be obtained by carefully removing the damaged parts of the tree and replacing them with new ones.