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Soft rot studies on CCA treated eucalypt power transmission poles
1981 - IRG/WP 1132
Initial results found for sixty CCA treated eucalypt poles, from a soft-rot survey are discussed. Retentions of CCA within above and below ground pole samples were variable. The variation was attributed mostly to biodegradation and effect of soil environment, rather than leaching. Bacterial decay was found in many poles and was severe in some cases. Although found in the presence of soft-rot decay, bacterial attack also dominated in regions of the CCA treated sapwood. Timber suffering such attack was appreciably softened. Extracellular layers have been observed around fungal hyphae from agar cultures and within soft-rot cavities. Fungal isolates were used to produce such polysaccharides. This material was used to observe the effect of addition of copper and quaternary ammonium compound. Solutions of extracellular polysaccharides exhibited some ability to bind copper and remove it from solution. In the presence of a quaternary compound polysaccharide was precipitated from solution.
L E Leightley


Extracellular layers of wood decay fungi and copper tolerance
1983 - IRG/WP 1180
Extracellular layers around the hyphae of brown, white and soft rot fungi have been examined using electron microscopy. These layers were isolated for identification. Particular interest was directed towards the extracellular layers of copper-tolerant soft rot fungi.
D M Francis, L E Leightley


Questionnaire - Fungal decay types
1985 - IRG/WP 1265
T Nilsson


Sequestration of copper ions by the extracellular mucilaginous material (ECMM) of two wood rotting basidiomycetes
2004 - IRG/WP 04-10533
The radial growth rate of colonies originating from either whole or ECMM-free inocula of Coriolus versicolor was investigated. The presence of ECMM allowed colonies to maintain higher growth rates than those form ECMM-free inocula up to 2 mM CuSO4 in the medium. The ECMM of C. versicolor and G. trabeum was able to reduce the diffusion of copper ions in solution. The ‘raw’ ECMM of both fungi had a greater ability to reduce the diffusion of copper ions than ECMM which had been subject to dialysis to remove soluble, low molecular weight components. The ‘insoluble’ fraction of ECMM for both species was more effective than the ‘soluble’ fraction at reducing the diffusion of copper ions. It is concluded that ECMM confers some protection to hyphae against the toxic effects of copper ions on growth in vivo and that this due to the binding of copper ions to both the polysaccharide and to low molecular weight components of the ECMM
D Vesentini, D J Dickinson, R J Murphy


Improvements of monitoring the effects of soil organisms on wood in fungal cellar tests
1996 - IRG/WP 96-20093
Accelerated testing the durability of preservative treated timber in a so called "fungal cellar" or "soil-bed" to evaluate its performance in ground contact is widespread practice. In order to obtain a more accurate and reproducible estimate of preservative performance, several institutes, among them the BAM in Berlin, have routinely carried out static bending tests in addition to visual examination. These tests were usually performed with a defined maximum load or deflection path regardless of the remaining degree of elasticity of the test specimens. Recent studies at the BAM revealed that by modifying the method, i.e. by restricting the applied load to the non-destructive interval for each individual test specimen, the calculated modulus of elasticity (MOE) reflect the changing strength properties caused by biological deterioration and allow within a relatively short time valuable predictions on the service life of the treated timber in soil contact.
I Stephan, S Göller, D Rudolph


The restricted distribution of Serpula lacrymans in Australian buildings
1989 - IRG/WP 1382
Temperature data has been gathered over a number of years, not only for flooring regions of various buildings in Melbourne, but also within roof spaces and external to the buildings. Findings are discussed in relation to the distribution of Serpula lacrymans within Australia, its restriction to certain types of building construction and its restriction to flooring regions. The subfloor spaces of badly-ventilated, masonry buildings are highlighted as being better suited than are the subfloor spaces of, for example, Japanese buildings for the activity of this fungus. Hence Serpula lacrymans is very restricted in its distribution in Australia, yet where it is active it does grow rapidly and causes rapid flooring failures.
J D Thornton


Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh


The accelerated field simulator (= fungal cellar)
1982 - IRG/WP 2170
G C Johnson, J D Thornton, H Greaves


Preventive action against fungal decay: A comparative experiment on the effects of natural and artificial infection of wood by Basidiomycetes
1981 - IRG/WP 2160
M Fougerousse


A short note on fungal decay in K33-treated poles
1982 - IRG/WP 1169
Soft rot cavities and erosion of the lumen have been found in K33-treated Pinus sylvestris poles from the years 1956-66 by microscopic studies. Poor treatment quality has been proved for some of these poles. The microscopy showed an unusual pattern of attack, and pre-treatment decay is suspected but not yet proved. Sounding the poles and using the Pilodyn indicated decay, but poking did not. Quantification of the attacks was possible only by microscopic studies.
H Friis-Hansen


Lignin degradation by wood-degrading fungi
1986 - IRG/WP 1310
The wood-degrading white-rot fungus Phanerochaete chrysosporium, has been the subject of intensive research in recent years and, based upon isolation of the extracelluar enzyme ligninase, major advances have now been made toward elucidating the mechanism by which this fungus degrades lignin. From these developments, a model emerges which could explain the process by which wood-degrading fungi in general, attack lignin.
P J Harvey, H E Schoemaker, J M Palmer


Evaluation of new creosote formulations after extended exposures in fungal cellar tests and field plot tests
2000 - IRG/WP 00-30228
Although creosote, or coal tar creosote, has been the choice of preservative treatment for the railroad industry since the 1920s, exuding or "bleeding" on the surface of creosote-treated products has been one incentive for further enhancements in creosote production and utility (Crawford et al., 2000). To minimize this exuding problem, laboratories such as Koppers Industries Inc., USA, and Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Chemical and Wood Technology, Melbourne, Australia, have developed changes in processing of coal tar that produce distillates with fewer contaminants. This "clean distillate" is then used to formulate "clean creosote" as a preservative. These new, unique creosote formulations are being investigated as part of a program to enhance the use of regionally important wood species in the United States. Four retention levels of each of two new creosote formulations creosote, one pigment-emulsified creosote (PEC) and one creosote formulation that meets the AWPA Standard C2-95 for P1/P13 creosote (AWPA, 1995a), were applied to two softwood species and two hardwood species. Two laboratory procedures, the soil-block and fungal cellar tests (accelerated field simulator), were used to evaluate the four creosote formulations. These procedures characterized the effectiveness of the wood preservatives. The soil-block tests were used to determine the minimum threshold level of the preservative necessary to inhibit decay by pure cultures of decay fungi. In general, the soil block tests showed there was little difference in the ability of the four creosote formulations to prevent decay at the three highest retention levels as summarized in a previous report by Crawford and DeGroot (1996). The soil-block tests will not be discussed in this report. Fungal cellar tests expose treated wood to mixtures of soil-borne fungi that promote accelerated attack. Crawford and DeGroot (1996) discussed the evaluation of the creosote formulations after 17 months of exposure in the USDA Forest Service, Forest Products Laboratory (FPL), fungal cellar. At that point in time data from the fungal cellar tests showed that softwoods are protected better than hardwoods for all four formulations of creosote tested. This report will discuss exposure of the fungal cellar stakes upto 36 months. In addition, field stake tests are being used to verify service life of the new creosote formulations in vivo. Results from accelerated tests are indicative of field performance, but the correlation between laboratory and field results is still being investigated. Field stake tests are regarded as critical, long-term evaluations that provide results most directly related to the performance of treated products in service. In this study, we report on the performance of the creosote formulations after five years of exposure in field tests.
D M Crawford, P K Lebow, R C De Groot


An attempt to evaluate wood resistance against fungal decay in non-sterile conditions by measuring the variation of resistance to bending test
1988 - IRG/WP 2308
The main object of this work was to determine the variation of strength on large test specimens of wood (800 x 45 x 45 mm³) when exposed to accelerated fungal attacks close to natural conditions, out of test vessels. The modulus of elasticity (MOE) and the modulus of rupture (MOR) have been assessed. Thereby, the natural resistance of the wood species to fungal decay, the efficiency of preservative as well as the treatment applied are discussed. The wood tested is a guianese secondary species (Couma guianensis). The fungi tested are two guianese strains of brown and white rot. The exposure time is 12 weeks. No mould contamination has been recorded by use of a selective fungicide. The results obtained show that it is possible to infest in nonsterile conditions large wood specimens. Furthermore, modulus of rupture appears to be the most reliable criterion. The investigation, that requires limited equipment and staff could be performed in any tropical research station as it has been done at CTFT, French Guiana center.
L N Trong


A direct method for testing plywood and particle boards against fungal decay
1984 - IRG/WP 2214
A method directly inspired from the French standard testing method of the resistance of particle boards against fungal decay (AFNOR N° 51.295 May 1980) is described. But in that experimentation, the infestation is localized and realized in non sterile conditions. Small blocks of Fagus sylvatica (60 x 20 x 10 mm³) used as " inoculates " are infested with basidiomycetes, in Kolle flask for 4 to 6 weeks, then tightly pressed against the middle part of the test specimens (190 x 15 x 15 mm³). The lower part of the inoculates is plunged in vermiculite kept constantly humid by water containing a selective fungicide. After twelve weeks of exposure in non sterile conditions, in a green house with constant temperature around 20°C, the test specimens are then submitted to a static bending test until fracture. The comparison of the fracture-stress between control test specimens and the specimens exposed to wood rotting basidiomycetes permits to evaluate the resistance of the studied materials against fungal decay.
L N Trong


Biological and chemical observation on the early fungal colonization of TBTO treated Swedish redwood stakes
1984 - IRG/WP 3311
Data on the early fungal colonization of Swedish redwood stakes, impregnated with 1% TBT0 / 0.5% dieldrin solution, both by double vacuum impregnation and immersion processes are presented. Results of chemical analyses of wood samples from the outer 1 mm of separate painted and unpainted stakes, exposed over the same twelve month period, are also discussed.
R Hill, A H Chapman, A Samuel, K Manners, G Morton


Isolation and identification of the fungal flora in treated wood
1976 - IRG/WP 144
J F Levy


Virulence tests with fungal strains used in EN 113 CEN ring test. Results with Coniophora puteana (Schum.ex Fr.) Karst
1986 - IRG/WP 2249
D Dirol


The influence of crystalline and amorphous cellulose on extracellular hydrogen peroxide production by brown-rot fungi
1991 - IRG/WP 1482
The production of hydrogen peroxide (H2O2) has been suggested to play a key role in the degradation of wood by wood-rotting fungi. The production of extracellular hydrogen peroxide was studied by a quantitative method which detects the oxidation of the 2,2-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) by H2O2 and horseradish peroxidase (HRP) in liquid culture medium. The carbon sources used were crystalline and amorphous cellulose. Two brown-rotters, Serpula lacrymans and Poria placenta, were able to produce clearly detectable amounts of extracellular hydrogen peroxide in liquid medium which contained crystalline cellulose as carbon source. No detectable H2O2 was produced in conditions where amorphous medium was used as carbon source. This result suggests that the conformational structure of the substrate may induce H2O2 production by brown-rot fungi.
A-C Ritschkoff, L Viikari


Are fungal cellar tests really necessary?
1989 - IRG/WP 2333
During the past decade the range of methodology used to evaluate wood preservative potential has significantly expanded. At the forefront of these new tools available to the scientist·is the fungal cellar. This technique, as currently applied, involves the exposure of treated and untreated samples to conditions of moisture and temperature which ensure optimum fungal attack. By comparison data with that obtained on similar preservative systems in conventional stake tests, acceleration factors for predicting performance have been developed. This discussion paper examines the philosophy influencing the development of fungal cellar testing, and provides an alternative viewpoint.
J N R Ruddick


Electron microscopic detection and chemical analysis of three-lamellar structures in wood-destroying fungi
1984 - IRG/WP 1240
In the course of transmission electron microscopical investigations of pine wood decay by various brown- and white-rot fungi extracellular three-lamellar structures (TLS) formed by the fungi were found in specimens stained with ruthenium red. These structures occured in the lumen of the wood cell surrounding the hypha at the outermost layer of the fungal cell wall. In the course of the investigations these structures were also detected in fungi cultivated with glucose on a rotary shaker, where they showed forms similar to tubuli and vesicles. The three-lamellar structures formed by the white-rot fungus Sporotrichum pulverulentum, which were contained in the outermost cell wall layer, were isolated by disintegration of the fungal pellet and subsequent digestion of the fungal cell wall by snail enzyme. It was found that these structures are resistant to the enzymatic digestion and are composed of 80 to 90% carbohydrates, mainly consisting of glucose monomeres, 5 to 10% proteins, containing 5 fractions with molecular weights between 30000 and 200000, and finally 5 to 10% lipids which do not contain any phospholipid.
R Foisner, K Messner, H Stachelberger, M Röhr


Targeting fungal proteinases to prevent sapstain on wood
1995 - IRG/WP 95-10097
Discoloration of wood, caused by a variety of sapstaining fungi, leads to periodic losses in the Canadian lumber export industry. Proteolytic enzymes are thought to be necessary for retrieval of nitrogen during fungal growth on wood. The major extracellular proteinase of Ophiostoma piceae, a representative sapstaining fungus, was purified to homogeneity and its inhibition pattern characterised. Classic serine proteinase inhibitors inhibited the activity of the purified proteinase in a dose-dependent manner. Several chelating agents, detergents, heavy metals and PQ-8, a currently used commercial antisapstain formulation, also caused a reduction in proteolytic activity in vitro. Selected inhibitory compounds were then tested for their effect on growth of Ophiostoma piceae in artificial media and on wood. Heavy metals and several chelators inhibited growth on media containing protein or inorganic nitrogen, suggesting that they were toxic to the fungus rather than specific to the proteinase. However, chymostatin and PQ-8 did appear to be specific proteinase inhibitors. These products caused a decrease in growth on a protein-supplemented medium which induces proteinase production, but had little effect on growth on medium containing inorganic nitrogen. Visual assessment of lodgepole pine sapwood samples inoculated with Ophiostoma piceae also identified PQ-8 as an effective inhibitor of fungal growth. Other pure chelators and serine proteinase inhibitors did not perform well on wood. While some compounds showed promise in these tests, definitive testing and commercial application are constrained by the current lack of stable, cheap, non-toxic, specific serine proteinase inhibitors.
L D Abraham, D E Bradshaw, A Byrne, P I Morris, C Breuil


Preliminary note on the fungal problem of rubber wood
1983 - IRG/WP 3246
Susceptibility of rubber wood to fungal attack limits its wider utilisation. Fungal problems encountered in treating rubber wood with boron compounds by diffusion process have been discussed. Sodium pentachlorophenoxide and 2-thiocyanomethylthio benzothioazole (TCMTB) were investigated for possible control of fungal growth during diffusion storage and their performance has been reported.
R Gnanaharan


Defining fungal decay types - Final proposal
1988 - IRG/WP 1355
The term soft rot is proposed for all forms of decay caused by Ascomycetes and non-basidiomyceteous Fungi imperfecti. The terms brown rot and white rot should be used only for decay caused by Basidiomycetes. Brown rot is characterized by extensive depolymerization of the cellulose and limited lignin degradation. White rot is characterised by significant degradation of the lignin component in wood.
T Nilsson


Fungal defacement of water-stored softwoods
1993 - IRG/WP 93-10009
Sapstain, mould and basidiomycete defacement of untreated sawn boards of Scots and Corsican pine was recorded during a 14 week field trial. Boards were cut from freshly felled logs and from logs previously maintained under water sprinklers for 6 months and ca. 4 years. The incidence of sapstain defacement or the freshly felled wood was very servere aftcr 2 weeks and remained so throughout the board trial. Fungal defacement of wood previously stored under sprinklers for 6 months was progressive and was severe by 14 weeks. In contrast, the level of defacement of boards from long lerm water-stored logs remained very low after 14 weeks exposure. The marked differences in susceptibility to fungal infestation of boards from freshly felled and water-stored logs are discussed in terms of wood sugar levels and the bacterial populations present in the wood.
M A Powell, R A Eaton


Efficacy of some extractives from Pinus heartwood for protection of Pinus radiata sapwood against biodeterioration. Part 1: Fungal decay
1995 - IRG/WP 95-30072
Chemical compounds thought to contribute to the natural durability of heartwood of Pinus spp. were either chemically synthesised in the laboratory or extracted from the heartwood of Pinus elliottii or Pinus caribaea. These compounds included the stilbenes, pinosylvin and its mono- and di-methyl ethers, and the flavonoids, pinobanksin and pinocembrin. Small blocks of Pinus radiata sapwood were impregnated with methanolic solutions of pure compounds or heartwood extracts, to a range of retentions extending above and below the concentration of each compound known to occur in the heartwood of Pinus spp.. Fungicidal efficacy of these compounds has been evaluated by exposure of treated blocks to pure cultures of a white and a brown rot, in addition to an unsterile soil test.
M J Kennedy, J A Drysdale, J Brown


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