House Fungus

HOUSE FUNGUS, various representatives of the class of fungi that develop on wooden parts of buildings and lead to their destruction. The following conditions are most favorable for the appearance of H. f.: dead wood of coniferous species, poor ventilation, dampness, absence of sharp temperature fluctuations and sharp changes in moistening and drying. As a conditional list, one can accept the 31 species of H. fungus given by Vanin in his 'Tables' (1926); the most frequently encountered are: Merulius lacrimans and Poria vaporaria. Since the 18th century, the Western European press has contained references to the great economic damage caused by H. f. (destruction of entire buildings), as well as the destruction of the most critical parts with collapses of plaster, floor partitions, etc. Similar indications are found in Russian literature from the middle of the 19th century. In connection with this, numerous proposals were made for disinfectants to combat H. f., and systematic measures for broad prevention were outlined. In Germany (1905), a special commission was created to research the biology of fungi, to clarify the sanitary significance of fungal damage, and to develop measures for combating them. On the initiative of this commission, a special laboratory for the study of H. f. was established in Eberswalde. In Russia, before the revolution, significant work was done in a similar direction by A. V. Sapozhnikov at the chemical laboratory of the St. Petersburg Institute of Engineers of Communication Routes, and then by K. Ya. Ilkevich (1911). Among modern works, the activity of the commission under the Administration of the Moscow Provincial Engineer (1927) should be noted; as a result of this work, a series of instructions was issued by the Moscow Provincial Engineer on combating fungus at all stages of the passage of lumber (forest plots, warehouses, newly constructed buildings, existing buildings). A number of provisions (methods of inspection, card accounting of damage, standardization of methods for testing disinfectants, etc.) were subsequently adopted on the report of P. P. Dyakonov by the XI All-Union Congress of Bacteriologists, Epidemiologists, and Sanitary Physicians (May, 1928). The external habitus of various species of H. f. in the stage of fully developed fruiting bodies is sufficiently characteristic for diagnosis, which is often possible based on mere inspection with the naked eye and with the help of a magnifying glass (general type of the fruiting body and its individual parts, relationship to the substrate), as well as by microscopy (type of spore-bearing outgrowths of the mycelium - basidia, nature of spore formation, appearance of spores). Based on the initial stages of mycelium, diagnosis cannot always be made and then only approximately. Here it is possible to recommend cultivating H. f. to the fruiting body stage in a compost heap, where fruiting bodies are obtained much more frequently than on artificial nutrient media (not always). Finally, diagnosis is also possible based on cords, which serve as conductors of water and nutrients for the fungi, in particular based on the type of hyphae contained in the cords. Among preventive measures for combating H. f., first place is given to maintaining proper conditions in the operation of existing, especially wooden, structures. Sources of dampening of those areas of wood that are protected from ventilation, covered with plaster, especially when covered with a waterproof layer, for example, oil paint, must be eliminated. These same points must be taken into account already in the designs and layout of newly constructed buildings; the requirement is put forward that wood for construction be taken from healthy forest plots, that it be kept in proper conditions in warehouses, and that it not be used when it contains more than 19% moisture. Due to the very wide distribution of spores and mycelium of fungi, they can be very often found on wooden building materials; this is of great importance only if such materials are damp, since H. f. can develop only under conditions of dampness. When fungal growth is detected, it is important to remove and burn on the spot the affected wood, but not to forget at the same time the indications of K. Ya. Ilkevich: 'By sanitizing (drying) our dwelling and even without removing the wooden parts infected with such a terrible H. f., which are still technically usable, we can stop the rotting of the wood and the filling-in forever.' See also Antiseptics for wood.