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Iron promotes decay capacity of Serpula lacrymans
1993 - IRG/WP 93-10008
The influence of iron and iron compounds on the decay capacity of Serpula lacrymans was studied. Mass losses of pine wood caused by dry rot fungus were increased when FeSO4 was added into the culture medium or when there were iron nails or stone wool on the culture medium. This supports the hypothesis that iron in stone-based building materials is one reason for the increased decay capacity of Serpula lacrymans.
L Paajanen

Report on the status of collaborative experiments within the Sub-group on Basidiomycete tests
1983 - IRG/WP 2194
This report summarises the results of co-operative work carried out within the Sub-Group on Basidiomycete tests up to December 1982. The principle findings are recorded in the Conclusions Section. Work intended between IRG-13 in Turkey and IRG-14 in Australia is cited under Future Programme. An Annex provides a response sheet for existing and new participants to notify their contributions.
A F Bravery

Some observations on miniaturised soil/block tests
1988 - IRG/WP 2317
Results are presented for miniaturised soil/block tests carried out in 120 ml capacity glass jars. The four test fungi (Coniophora puteana, Coriolus versicolor, Gloeophyllum trabeum and Poria placenta) reacted differently to different moisture regimes established by varying the soil moisture content. Acceptable levels of decay were achieved by the three brown rot fungi with soil at 110% whc; however, soil at 150% whc failed to provide a high enough moisture content in the test blocks for decay by the white rot Coriolus versicolor. Overlaying test blocks exposed to Coriolus versicolor with moist sterile vermiculite increased both moisture contents and decay.
J K Carey

A new laboratory technique devised with the intention of determining whether, related to practical conditions, there should be a relationship between growth rate and decay capacity (of different strains) of Serpula lacrymans
1989 - IRG/WP 1384
Most laboratory techniques for the determination of growth rate not only use a medium (agar) unrelated to practice, but also yield values that are often far less than those found in practice. Also, most laboratory techniques for the determination of decay capacity ensure that the whole of a small test block becomes fully surface-colonised within the first few days; whereas in Australian practice Serpula lacrymans most often grows in one direction, from the walls across floorboards, with resulting collapse first evident near the ends of boards adjacent to that wall. This paper reports on a new, medium-scale, laboratory technique enabling growth rate measurements and (subsequently) a decay capacity measurement, all using the same piece of timber. Eight strains of Serpula lacrymans have been used in the three evaluation experiments carried out to date. Mean values for growth rate on wood have been suitably high, probably as high as for the most favourable practical situations. Resulting mass losses have, as was intended, been reduced in comparison with values previously obtained in small-scale techniques. This direct technique has confirmed the conclusions that others have made based on their comparisons; that it seems unlikely that the pattern of differences between growth rates of different strains has any consistent similarity with their corresponding decay capacities.
J D Thornton

Iron in stone wool - one reason for the increased growth and decay capacity of Serpula lacrymans
1992 - IRG/WP 92-1537
The chemical compositions of stone wool and glass wool were analysed. There was more iron in the stone wool than in the glass wool. It was found that iron present in stone wool was easily dissolved by oxalic acid that Serpula lacrymans is able to produce. The stone wool promoted the decay of pine wood by Serpula lacrymans. The glass wool had no effect on the decay capacity of Serpula Iacrymans. The iron derived from the stone wool may be one reason for the increased growth and decay capacity of Serpula lacrymans. Transition metals (Fe2+, Mn2+, etc.) combined with hydrogen peroxide (H2O2) are believed to be necessary for the oxidative breakdown of polysaccharides.
L Paajanen, A-C Ritschkoff

Soil-bed studies. Part 2: The efficacy of wood preservative
1983 - IRG/WP 2205
Various methods of decay assessment were investigated. Three stages or phases of decay were identified which could be used to describe the efficacy of a preservative system or virulence of a soil-bed testing medium. These included the lag, decay, and senescent phase. Premature senescence could arise if wood samples became waterlogged. It was concluded that time to failure was unsuitable as a method of decay assessment. Decay assessment by deflection testing was therefore limited to assessing linear losses in elasticity against time.
P Vinden, J F Levy, D J Dickinson

Preliminary studies to assess the effects of aeration and lowered humidity on the decay capacity, growth and survival of the dry rot fungus Serpula lacrymans (Wulf ex. Fr.)
1997 - IRG/WP 97-10208
Novel microcosms were used to test separately the effects of aeration and humidity on the decay capacity, linear spread and survival of Serpula lacrymans. The application of a pumped air supply resulted in an effective cessation of fungal activity when all but the lowest of the air flow rates was used. Furthermore, the lowest air flow rate caused marked growth tropisms away from the stress. In separate chambers used to create a range of relative humidities, growth and decay were permitted only in the higher humidity regimes. In both the air flow and the humidity experiments, the loss of growth and decay abilities was not always accompanied by a loss of fungal survival. A test to compare the decay capacities of domestic building isolates and "wild" Himalayan isolates of S. lacrymans was also performed, as were comparisons of radial growth rates on malt agar. Significant differences between the two groups occurred in both tests.
G A Low, J W Palfreyman, N A White, H J Staines, A Bruce

A study of the colonization of wood blocks in a laboratory unsterile soil test
1988 - IRG/WP 2318
CCA treated and untreated beech blocks were exposed to a defined horticultural loam using the method proposed for the collaborative soft rot test in the soft rot sub-group of Working Group Two. At intervals during the incubation wood samples were removed and fungal isolations were made using selective media. Fungi were identified and tested for their cellulolytic ability and their decay capacity in beech in pure culture. Replicate wood samples were examined by microscopy for colonisation and decay.
M T De Troya, S M Gray, D J Dickinson

The effect of added nutrients on growth rate and decay capacity of Serpula lacrymans
1990 - IRG/WP 1427
At the previous meeting a new technique was presented that enables both fungal growth rate and wood decay rate to be measured using the same timber specimen. The technique (IRG/WP/1384) has previously been carried out with 1% malt as the sole nutrient within the small jar that provides the inoculum for this method. Results presented here relate to an additional level of 5% malt, with or without a nitrogen source in the form of ammonium sulphate at either 0.01 g or 1.0 g per litre. Two isolates of Serpula lacrymans (one of European and one of Australian origin) were used at a temperature setting of 20°C. The linear growth front was measured, on the 200 mm long specimens of Pinus radiata sapwood, between 10 and 21 days after the specimens were introduced to the inoculum. Mass loss values of these same specimens were determined after 12 weeks' exposure. Replication comprised three specimens, within each of three large jars, of each treatment. For both strains, increasing the malt level caused some reduction in growth rate, with the addition of nitrogen resulting in no further growth rate changes. In contrast, mass loss of timber was increased for both strains at the higher malt level. Furthermore, for each of the two malt levels tested, the mass loss due to both strains was further increased at the high nitrogen level.
J D Thornton, A McConalogue

A comparative analysis of Coniophora olivacea (Fr. ex Pers.) Karst. and Coniophora puteana (Schum. ex Fr.) Karst. test strains
1993 - IRG/WP 93-20004
Investigations were carried out to compare pure cultures of Coniophora olivacea (Fr. ex Pers.) Karst. used as a test fungus in Australia and other Pacific countries, and Coniophora puteana (Shum. ex Fr.) Karst. which is used in Europe. Comparisons included morphology, growth rate and dry mass of mycelium, decay capacity, influence of temperature, toxic value of CCA and quaternary ammonium compound (QAC) in both an agar-plate method (ED50, ED100, LD100), and a modified agar-block method. The fungi were found to be similar in many respects.
J Wazny, L J Cookson

A comparison of fungal strains used in the bioassay of wood preservatives
1984 - IRG/WP 2220
Previously published data are presented relating to a number of strains of wood-destroying basidiomycetes (Coniophora puteana, Coriolus versicolor, Gloeophyllum abietinum, Gloeophyllum sepiarium, Gloeophyllum trabeum, Lentinus lepideus, Poria placenta, Fibroporia vaillantii and Serpula lacrymans) commonly used as test fungi in the bioassay of wood preservatives. The data, which has not been statistically compared, consists of mycelial growth rates, decay capacities, and toxic values using agar, agar-block and soilblock methods based on data published over a period of almost 50-years. In many cases a large variation can be observed between strains originating from the same geographical region and between strains from different climatic-geographical zones. The differences between individual sub-cultures of the same strain, as used in various laboratories - or even in the same laboratories - are noted. Many of the published bioassay methods contain insufficient detail to make statistical assessments. Therefore, the authors have not attempted a definitive comparison of the numerous data. A proposal is presented to organize an international resource of pure cultural strains used as test organisms in bioassays of wood fungus may be dictated by local requirements.
J Wazny, H Greaves

A comparison analysis of eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray
1991 - IRG/WP 2362
Investigations were previously carried out to compare eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray (some used in various countries as standard test strains): FPRL 12C (England), FPRL 12E (Germany), Warsaw III (Poland), HFP 7802 (Japan), DFP 16508, 16509, 16521 and 16522 (Australia). Studies included growth rate and dry mass of mycelium, decay capacity, reduction of compression strength, toxic values of CCA and NaPCP tested with agar-plate method (ED50, ED100, LD100) and a modified agar-block method using mass-loss and reduction of compression strength criteria. All of the data obtained are presented here together for the first time, in both table and graphic formats. Further comparison between these results will be presented later (in the final part of the series in 'Holzforschung').
J Wazny, J D Thornton

Effect of fungal attack on maximum load capacity of simulated wall assemblies
2007 - IRG/WP 07-20363
The effects of moisture intrusion and fungal attack on the maximum load capacity of nailed assemblies was investigated using one white and one brown rot fungus against 4 material combinations over a 20 week period. Wetting significantly reduced the maximum load capacity of all four material combinations, while wetting and autoclaving only affected the OSB sheathing/spruce stud. The white rot fungus (Trametes versicolor) had no significant effect on the maximum load, while the brown rot fungus (Gloeophyllum trabeum) produced significant load reductions on shear connector assemblies with OSB sheathing. Results indicate that moisture remains the dominant factor in the performance when water intrudes into wall assemblies.
N Melencion, J J Morrell

Impact of water holding capacity and moisture content of soil substrates on the moisture content of wood in terrestrial microcosms
2019 - IRG/WP 19-20662
Terrestrial microcosms (TMC) are frequently used for testing the durability of wood and wood-based materials as well as the protective effectiveness of wood preservatives. In contrary to experiments in soil ecology sciences, the experimental set-up is usually rather simple. However, for service life prediction of wood exposed in ground, it is of immanent interest to better understand the different parameters defining the boundary conditions in TMC. This study focussed therefore on the soil-wood-moisture interactions and their potential effect on durability testing in TMC. TMC were prepared from the same compost substrate with varying water holding capacity (WHC) and soil moisture content (MCsoil). Wood specimens were made from English oak, Beech, Douglas fir, and Scots pine sapwood and exposed to in total 48 different TMC and wood moisture content (MCwood) was studied as well as its distribution within the specimens. For this purpose the compost substrate was mixed with sand and turf and its WHC was determined using two methods in comparison, i.e. the ‘Droplet counting method’ and the ‘Cylinder sand bath method’ in which the latter turned out advantageous over the other. MCwood increased generally with rising MCsoil, but WHC was often negatively correlated with MCwood. Instead, the degree of water saturation Ssoil could serve as a more predictive measure for MCwood in soil exposure scenarios. With increasing Ssoil the MCwood increased, but followed wood species-specific curves with differently steep increase and a plateau at Ssoil = 0 %. In addition, Ssoil from which MCwood increased most intensively was found to be wood-species specific and might therefore require further consideration in soil-bed durability testing and service life modelling of wooden components in soil contact.
C Brischke, F L Wegener

Decay capacity and degradation patterns of Xylaria hypoxylon on different wood species
2022 - IRG/WP 22-10985
A host of physical and environmental factors may influence fungal decay including the wood substrate, temperature, moisture, oxygen, light, pH, and nitrogen. Understanding the effects of these factors on fungal decay is important for the effective utilization of wood decay fungi in biotechnological processes and for understanding the role of these organisms in global carbon cycling. The ascomycete Xylaria hypoxylon causes white rot of hardwoods, but remains relatively under-characterized. In this investigation, the decay capability of this fungus was studied using beech, hornbeam, oak and pine. Although Xylaria species are considered as causing white rot decay, Type II soft rot erosion was observed on hornbeam, Type I soft rot cavities were noted on beech, simultaneous rot was found on oak and selective rot on pine. Results indicated that both wood species and cell wall chemistry affected morphological decay patterns illustrating the relationships between fungal enzymatic capacity and wood cell wall structure/chemistry.
E Bari, G Daniel, A Singh, J J Morrell

Confocal laser scanning microscopy of a novel decay in preservative treated radiata pine in wet acidic soils
1997 - IRG/WP 97-10215
Light microscopy of radiata pine (Pinus radiata D. Don) field test stakes (20x20x500mm3) exposed in wet acidic (pH 3-4) soil for 12 - 24 months showed predominance of an unusual type of decay characte-rised by tunnelling attack of wood cell walls. After two years decay was moderate to severe in wood treated to ground contact CCA specifications and also equivalent retentions of creosote, and a number of new generation preservatives. Relative to other New Zealand temperate test sites and also an Australian tropical site, the New Zealand acidic soil test site was very aggressive. Correlative scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to elucidate the micromorphology of this attack. Tunnels of diameter 0.2-5 µm were present throughout all layers of the cell wall, and their orientation was not related to cellulose microfibril orientation. They also showed no preference for particular cell wall layers, indicating a lignin degrading capability. CLSM images showed that living, connecting fungal hyphae were present in the cell lumina and tunnels. This type of attack was predominant in wood that was highly saturated with water whereas wood that was less moist was predominantly attacked by classical white rot. Ongoing isolation and incubation studies in conjunction with further microscopy should enable identification of the fungal species involved.
R N Wakeling, Ying Xiao, A P Singh

Effect of acetylation on decay resistance of wood against brown-rot, white-rot and soft-rot fungi
1989 - IRG/WP 3540
Effect of acetylation on decay resistance of wood was investigated using wood blocks of Cryptomeria japonica, Pinus densiflora, Albizia falcata and Fagus crenata. Blocks were treated with uncatalyzed acetic anhydride for different lengths of time and exposed to Tyromyces palustris, Serpula lacrymans, Coriolus versicolor and unsterilized soil. The action of OH-radical on acetylated wood was also examined using Fenton's reagent. The enhancement of decay resistance by acetylation was revealed clearly for all cases of exposures but varying with fungal and wood species used. For a brown-rot fungus Tyromyces palustris, the weight loss reached almost nil in all woods at 20 WPG (weight percent gain) of acetylation, after the striking decrease from 10 to 15 WPG. For a white-rot fungus Coriolus versicolor, it was counted until 12-15 WPG in the perishable hardwoods used, but not in a softwood Cryptomeria japonica, even at 6 WPG. In cases of another brown-rotter Serpula lacrymans and soil burial, effect of acetylation was intermediate between Tyromyces palustris and Coriolus versicolor. Anti-degradation mechanism by acetylation was discussed, from these weight loss - weight gain relationships, and the IR-and 13C-NMR spectral analyses of fungus-exposed wood.
M Takahashi, Y Imamura, M Tanahashi

Field trial with poles of Scots pine treated with six different creosotes
1996 - IRG/WP 96-30115
In the middle of the 50's field trials with creosote-treated poles were started in France, Germany and Sweden. The trials were initiated by WEI (Western-European Institute for Wood Preservation). Six different creosotes were used and 40 poles per creosote were installed at each test field. Results after 39 years of exposure in Simlangsdalen, Sweden are reported. Poles treated with a heavy creosote were less decayed than poles treated with medium-heavy creosotes. Poles treated with a light creosote were most decayed.
Ö Bergman

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

JWPA method for testing effectiveness of surface coatings with preservatives against decay fungi
1981 - IRG/WP 2164
In 1979 JWPA established a new method for testing effectiveness of surface coatings in accordance with practical use of preservative-treated lumber. Comparing the new testing method with JIS A 9302, a few new trials - size of wood specimen, weathering procedure, and decay-test procedure - are incorporated.
K Tsunoda

Utilization of curcumin for detection of presence of boron in wood
1982 - IRG/WP 3191
It has been shown that curcumin is not a reliable reagent for detecting boron in wood that has been attacked by fungi
M-L Edlund

Co-operative studies on determining toxic values against wood-destroying Basidiomycetes: Progress report to May 1989
1989 - IRG/WP 2339
This document reports progress on the co-operative study between nine laboratories set up following the proposals contained in Document IRG/WP/2316. Results have been received from two laboratories. Toxic values data have been established successfully using the test fungus Coniophora puteana but problems have been encountered with the other test fungi.
A F Bravery, J K Carey

Monographic cards for wood-destroying fungi. [Fiches monographiques pour les champignons lignivores]
1970 - IRG/WP I 5B
C Jacquiot

On Donkioporia expansa (Desm.) Kotl. & Pouzar
1986 - IRG/WP 1285
Donkioporia expansa is found more often in houses than realised until now. Virulence tests according to EN 113 show not only an attack of oak, but also of other hardwoods and even soft-woods.
G Buchwald

Nondestructive Evaluation of Oriented Strand Board Exposed to Decay Fungi
2002 - IRG/WP 02-20243
Stress wave nondestructive evaluation (NDE) technologies are being used in our laboratory to evaluate the performance properties of engineered wood. These techniques have proven useful in the inspection of timber structures to locate internal voids and decayed or deteriorated areas in large timbers. But no information exists concerning NDE and important properties of wood composites exposed to decay fungi. For our pilot study on several types of wood composites, we examined the relationship between nondestructive stress wave transmission, decay rate and the bending properties of OSB exposed to the brown-rot fungus, Gloeophyllum trabeum (MAD-617). The following measurements were taken: stress wave transmission time (pulse echo test method), static bending test (ASTM D3043-95), and decay (expressed as percent weight). Stress wave measurements correlated with strength loss and with increasing rate of fungal decay. Stress wave NDE has great potential as a method for inspection of wood composite load-bearing (in-service) structures, detection of decay in laboratory tests, assessment of chemical additives to improve wood composite durability, and prediction of long term composite performance.
B Illman, V W Yang, R J Ross, W J Nelson

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