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Observations on the colonization of freshly-felled timber treated with prophylactic chemicals by mould and sapstain fungi
1989 - IRG/WP 1394
Field tests using freshly felled pine sapwood were set up to determine the effectiveness of a range of antisapstain compounds and to study the problems of colonization by mould and sapstain fungi. Differences were recorded both in the overall performance of the compounds and also their selectivity in controlling specific fungal types. These results were found to be useful in gaining a better understanding of biocide - fungal interactions.
G R Williams, D A Lewis

Determination of the preventive efficacy against wood destroying basidiomycetes fungi, EN V 839 - CEN/TC 38 WG 9
1993 - IRG/WP 93-20015
The WG 9 of CEN TC/38 has presented to EC a mycological test to assess efficacy of preservatives applied by surface process. This method is now an experimental standard (EN V 839) which has to be approved by the different european delegations. The following paper is not the standard as it has been proposed but is a presentation of the principle of the method. The experimental standard specifies a laboratory method of test which gives a basis of the assessment of the preventive action of a wood preservative when applied as a surface treatment against Basidiomycetes fungi. This method is applicable to formulations of preservatives in a ready to use form (organic formulations, organic water-dispersible formulations, water-soluble materials). Series of susceptible wood species specimens are treated on longitudinal faces whith the preservative in test using brushing as surface procedure. Test specimens are then exposed by an intermediate mesh to feeder blocks infestedby pure culture of Basidiomycetes fungi in sterile conditions and penetration of fungi is assessed on cross section sawn in the samples at the end of the test.
D Dirol

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

Some wood-destroying Basidiomycetes. Volume 1 of a collection of monographs
1981 - IRG/WP 1121
One of the first tasks of the International Research Group on Wood Preservation, when it began its work in 1969, was to compile a series of reports on the common decay fungi which can attack wood. This volume, which contains the first of these reports, has been compiled with the help of mycologists and wood preservation specialists in France, Ghana, the Federal Republic of Germany, the Netherlands, Poland, Sweden and Switzerland, and the United Kingdom. It gives up-to-date information on fifteen common Basidiomycete fungi and indicates the gaps in the world's present knowledge that exist about these.
R Cockcroft

Moisture requirements and wood degradation of pine and spruce wood by some Basidiomycetes-fungi
1989 - IRG/WP 1406
The minimum moisture requirements for the growth of the brown rot fungi, Coniophora puteana, Gloeophyllum trabeum and Serpula lacrymans were near or above the fibre saturation point of pine and spruce, sap and heartwood, during 160 days incubation according to the standard method EN 113. The moisture of wood for the optimum growth of Coniophora puteana and Serpula lacrymans was about 35-80% and for Gloeophyllum trabeum about 60-250% depending on the state of decay and wood species. The moisture content of wood was increased by the fungi, and there was a positive regression between the weight loss and the moisture content of wood. The effect of Coniophora puteana and Serpula lacrymans on the moisture content of wood was near to assumed values calculated according to the loss of carbohydrates. The effect of Gloeophyllum trabeum on the weight loss and moisture of wood was very fast and strong. The samples of pine heartwood were during 60 days incubation quite durable against the studied fungi, but after 120 days its resistance broke down. The weight losses of other studied wood types were higher.
H Viitanen, A-C Ritschkoff

An attempt to develop a direct and reliable method for testing the preventive action of preservation treatments of wood against fungal decay
1980 - IRG/WP 2139
In wood preservation there are two classical ways for assessing the reliability of preventive treatments against wood decay: the laboratory tests in which the various parameters are evaluated independently and the field tests or service tests in which those parameters are acting together in the natural environment. One has always tried to build bridges between the two types of experiments and to establish correlations between their results, but a rather large gap is still persisting. The aim of the research which is reported was to develop a method for testing directly the preventive action against basidiomycetes decay when the treatments do not lead to a full impregnation of the wood, but only raise a barrier of limited depth. A method has been developed, testing the wood specimens (of various sizes and shapes for representing various types of end-uses) out of test vessels, i.e. in non sterile conditions, but with well checked pure cultures. The various steps of the research are exposed and the results so far obtained allow to expect some interesting possibilities of testing directly, rapidly and accurately the resistance of any wood product, in its ready to use form, to decay by basidiomycetes.
M Fougerousse

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

Control of sapwood-inhabiting fungi by fractionated extracellular metabolites from Coniophora puteana
1991 - IRG/WP 1494
The objective of this study was to test the fractionated metabolites released by Coniophora puteana for their antagonistic activity against the sapstain fungi Ceratocystis coerulescens and Aureobasidum pullulans, and the molds Asperigillus niger and Penicillium spp. The acetone-soluble fraction obtained from the culture filtrate prepared from Coniophora puteana grown on 6% malt extract agar inhibited mycelial growth in a plate bioassay. The <5k-Da fraction separated from the acetone-soluble fraction also inhibited mycelial growth in the plate bioassay and prevented attack by Ceratocystis coerulescens in wood.
S C Croan, T L Highley

Assessment of the Inhibition of wood decay fungi by volatile organic compounds identified from Trichoderma spp.
1999 - IRG/WP 99-10302
Previous research identified five volatile organic compounds produced by Trichoderma spp. that may be inhibitory to wood decay fungi. The effects of four of these volatile organic compounds, 2-propanone, 2-methyl-1-butanol, heptanal and octanal were tested over a range of concentrations against four selected wood decay fungi. The fungi were incubated in malt extract broth under appropriate conditions and growth was estimated by biomass production and respiration rates. The results indicated that the growth of all four fungi were affected by at least one of the compounds, usually by inhibition but in rare cases stimulation. One of the four compounds, heptanal completely inhibited the growth of three of the four fungi and significantly inhibited the growth of the fourth. The implications of these results for the biological control of wood decay fungi and future studies are discussed.
S N Humphris, R E Wheatley, A Bruce, C Payne

Screening of the efficacy of tall oils against wood decaying fungi
2004 - IRG/WP 04-30354
Tall oil is a by-product in pulping of resinous wood by the sulphate process. Tall oil contains a complex mixture of wood extractives. Some of these extractives act as natural protection against wood decaying fungi while other serve as nutrition for the fungi. This report describes a screening of the efficacy of four refined tall oils with different chemical composition on wood decaying fungi. Testing was performed as filter paper assay and mini-block assay. In the filter paper assay growth rates of the white rot fungus Coriolus versicolor and the brown rot fungus Poria placenta were inhibited by the tall oils. None of the oils caused total inhibition of the fungi but there was a clear pattern towards increased efficacy with increased portion of resin acids in the oils. Impregnated mini-blocks with approximately 200 kg/m3 retention of tall oil after leaching showed an evident effect against Coniophora puteana and Poria placenta compared to untreated control samples. However, using the criteria from EN 113 requiring less than 3% mass loss, tall oil failed. The results indicate that decay resistance of tall oil impregnated Scots pine sapwood to the retention level used in this study is comparable with the decay resistance of Scots pine heartwood. It was expected that the efficacy of the tall oils was related to chemical composition of the oils. This was confirmed for the filter paper assay where the efficacy increased with increasing amount of resin acids. However, this pattern was not found for the mini-block assay. The protective effect of the tall oils in wood seems therefore to be more related to their hydrophobic properties than to their fungicidal properties.
G Alfredsen, P O Flæte, A Temiz, M Eikenes, H Militz

Siderophore production by Trichoderma spp. and its importance in the biological control of wood decay fungi
1994 - IRG/WP 94-10070
Competition for iron as well as other micro-nutrients is an essential component of the microbial ecology of many ecosystems. A wide range of micro-organisms including fungi and bacteria have been shown to increase their ability to efficiently capture iron through the production of specialised iron chelating compounds called siderophores. Since iron is in low supply in wood and has been implicated in the wood decay process by basidiomycete fungi, it is likely that any colonising organism which can capture the available iron may well act to biologically control the decay organisms. Many authors have reported that Trichoderma spp. can be used to control basidiomycetes (especially on agar systems) and a number of active mechanisms of antagonism have been identified. These have included competition for nutrients, mycoparasitism, antibiosis and production of volatile antibiotics. Little, however, has been reported on the importance of siderophores in the biological control of wood decay fungi. This paper reports on the ability of Trichoderma isolates to produce both phenolate and hydroxymate type siderophores and examines the potential role of such compounds in the biological control of wood decay fungi by Trichoderma isolates.
U Srinivasan, A Bruce, T L Highley

The effect of alternative pre-conditioning procedures on the durability of wood based board materials to decay fungi
1997 - IRG/WP 97-20105
In the biological testing of wood based board materials it has been shown that exposure of boards in a closed vessel system may lead to inaccurate results due to the build up of volatile substances that inhibit the test fungi. It is thought that this is a transitory effect of freshly manufactured boards. In the European standard for testing fungal durability of board materials which is currently under development (DD-ENV 12038:1996), a leaching pre-conditioning method is used to remove this effect. A variety of alternative ageing procedures have been studied, including natural weathering, leaching and evaporative procedures, to determine the most appropriate pre-conditioning protocol for the decay test. Our results show that there are procedures which are more efficient, and possibly more meaningful in terms of effectiveness or appropriateness of regime for use on board specimens.
S F Curling, R J Murphy, J K Carey

Window test. Direct testing of wood resistance to decay: A study of its fitness, its reliability and its accelerating factor
1984 - IRG/WP 2219
This is the results of an experiment using the window-test specimens, exposing the specimens to three different types of testing procedure: 1. Natural infestation in the open air; 2. Artificial infestation and exposure in the open air; 3. Artificial infestation in a green-house. The results show good similiraties of the three parallel tests in term of decay, and assess the reliability of the window-test, its fitness and particularly its accelerating factor.
G R Y Déon, L N Trong

Proposal for a simple methodology for the evaluation of the preventive effectiveness of protectors applied in superficial treatments against basidiomycetes fungi
1999 - IRG/WP 99-20167
Due to the considerable effect that the relation between the lateral surface and the volume of wood blocks has on superficial treatments, this work has attempted to determine the ideal size which allows to evaluate the effectiveness of a preservative in the shortest possible time. Three wood blocks of different dimensions were tested. In addition, as it is necessary to neutralise the effect of the heads for superficial treatments, two kinds of sealant which are clearly affected by the size of the wood blocks (inert and active sealants), were also studied. Likewise, two kinds of superficial treatments (deeping and brushing) were analysed. The possible influence of the size and form of the wood blocks in preventive effectiveness was determined by the weight loss they suffered after 12 weeks of incubation on Gloeophyllum trabeum cultures in malt agar. As was expected, the results obtained showed the greatest degradation on smaller wood blocks. For this reason, larger wood blocks should not be used for tests of this kind, as these did not undergo significant weight loss under these two test conditions during the study. Regarding the sealant, it has been proved that inert sealant influences the fungi activity less than the active sealant. Finally, no differences as to the kind of superficial treatment were observed.
M T De Troya, A Navarrete, F Rubio, M Yuste, C Rodríguez-Borrajo, D Muñoz-Mingarro, F Llinares

A possible role of unique TCA cycles in wood-rotting basidiomycetes
2003 - IRG/WP 03-10461
The copper tolerant brown-rot fungus, Fomitopsis palustris, acquires metabolic energy by use of the constitutively-occurring Kornberg’s glyoxylate cycle coordinating with oxalate biosynthesis and glucose oxidation (Erman Munir et al. Proc. Natl. Acad. Sci. USA, (2001) 98, 11126-11130). Furthermore, this fungus does not have the normal TCA cycle, lacking 2-oxoglutarate dehydrogenase which is a key ezyme of the TCA cycle of most living things. This paper reports that most wood decay fungi tested lack 2-oxoglutarate dehydrogenase (ODH) and that much greater activities of glutamate dehydrogenase compensating the absence of ODH were detected from both white- and brown-rot fungi.
E Munir, T Hattori, M Shimada

Colonization of treated and untreated ponderosa pine exposed in Hilo, Hawaii
1995 - IRG/WP 95-20068
The rate of decay in above ground exposures is largely controlled by rainfall and temperature, factors which can be used to construct a climate index of decay hazard in above ground exposures. Developers of new biocide formulations have utilized this knowledge by establishing test sites in sub-tropical regions such as the Gulf Coast of the United States. More recently, field sites have been located in regions with even higher climate indices with more severe risks of decay. One such site is Hilo, Hawaii which receives nearly 4000 mm of rainfall per year and has near optimal temperatures for microbial growth. Previous field trials have shown that untreated control L-joints fail in as little as one year at such sites, but the organisms associated with these failures and their interactions in the deterioration process remain poorly understood. It has been suggested that results from such tests may be poor indicators of chemical performance under less severe exposures. To address this issue, the fungal flora colonizing wood was assessed in L-joints and deck boards exposed above ground in Hilo, Hawaii. The samples were either untreated or treated with 0.5% triazole 1, 0.5% tributyltinoxide, 0.5% 3-iodo-2-propynyl butylcarbamate, or 0.25% triazole 2 in mineral spirits or water. Selected samples were removed periodically and cultured for the presence of decay fungi. While basidiomycetes were not prevalent among the initial colonizers, they became increasingly abundant after 18 months of exposure. Among the fungi isolated were Trametes versicolor, Fomitopsis meliae, Schizophyllum commune, and Antrodia sinuosa. These fungi are also found under more temperate exposures suggesting that data from tropical sites represents a similar, albeit more accelerated, progression of decay organisms. Further studies on the decay capabilities of selected isolates are underway.
C M Freitag, J J Morrell, K J Archer

Development of a mini-block test method for the rapid evaluation of preservative performance against Basidiomycte fungi
1991 - IRG/WP 2379
Screening procedures for new biocides used as wood preservatives can be a time consuming process using conventional Basidiomycete assay procedures. This is due mainly to the long exposure periods required to achieve adequate levels of decay (weight loss) in the test blocks. A number of alternative methods have been developed but most utilise artificial substrates such as filter paper or agar in which inhibition of growth is the main criterion of efficacy assessment. Whilst these methods can provide a comparison of biological activity towards target fungi, they omit the interaction between wood substrate and active ingredient. A further limitation is the inability of these methods to determine preservative performance. A test method has, therefore, been developed based on conventional methodology but using small dimension samples and a reduced exposure period (3 weeks). Results have indicated good test reproducibility with high weight losses of untreated controls. Large numbers of active ingredients or formulations can be rapidly screened using this method and the data can be further used for the estimation of treatment concentrations required for more formal basidiomycete tests such as EN 113.
J Brown, S Caswell, G R Williams

Evaluating the performance of wood preservatives against fungi
1974 - IRG/WP 247
A compilation is made of results published by various workers for agar/block laboratory tests of the effectiveness of wood preservatives against 11 species of wood destroying Basidiomycetes and one species of soft rot fungus. Preservatives include creosote, boron, metal/arsenic mixtures, metallic naphthenates, chlorinated naphthalene, chlorinated phenols and tri-n-butyl tin oxide. The results are compared statistically and the causes of the variance between different estimates examined. The limitations of agar/block and other laboratory tests as predictors of performance in the evaluation of preservatives are discussed.
R Cockcroft

List of fungi observed in avalanche barriers located in subalpine and alpine regions
1970 - IRG/WP 17
In the Subalpine region (Schilt-Stein; 1400-1500 m above sea level) the following fungi were observed: Basidiomycetes: Corticium alutaceum, Corticium ochraceum, Corticium sp., Collybia sp., Dacryomyces deliquescens, Exidia glandulosa, Lenzites abietina, Lenzites sepiaria, Lenzites trabea, Osmoporus odoratus, Peniophora pubera, Peniophora sp., Polystictus abietina, Poria placenta, Poria mucida, Poria versipora, Poria sp., Schizophyllum commune, Stereum sanguinolentum. In the Alpine region (Dorfberg-Davos; 1900-2500 m above sea level) the following fungi were observed: Basidiomycetes: Corticium alutaceum, Corticium ochraceum, Cyphella sp., Dacryomyces deliquescens, Exidia glandulosa, Flammula sp., Hydnum alutaceum, Hymenochaeta fuliginosa, Hypholoma sublateritium, Lenzites abietina, Lenzites sepiaria, Mycena sanguinolenta, Nematoloma fasciculare, Osmoporus odoratus, Peniophora gigantea, Peniophora pubera, Peniophora subtilis, Peniophora sp., Phellinus nigrolimitatus, Polyporus adustus, Polyporus fragilis, Polystictus abietina, Poria medulla panis, Poria placenta, Poria reticulata, Poria taxicola, Poria vaillantii, Poria vaporaria, Poria versipora, Schizophyllum commune, Stereum sanguinolentum, Trametes pubescens, Trametes serialis Ascomycetes: Geoglossum sp., Lachnea scutellata, Otidea sp. Myxomycetes: Acryria punicea, Stemonitis fusca.
O Wälchli

Development and Implementation of a DNA – RFLP Database for Wood Decay and Wood Associated Fungi
2004 - IRG/WP 04-10527
We are developing Restriction Fragment Length Polymorphism (RFLP) and Internal Transcribed Spacer (ITS) sequence databases for wood decay basidiomycetes and other fungi associated with wood. These databases currently house information for 39 fungal species consisting of 9 brown-rot basidiomycetes, 12 white rot basidiomycetes, 1 soft rot, 1 stain fungi, and 16 molds or other ascomycetes or imperfect fungi. We plan to add 6 brown rot, 14 white rot and 8 other species that we have in culture by summer 2004. Using the RFLP database, we were able to identify wood decay basidiomycetes that were isolated from a local forest and that could not be distinguished based on morphology. In addition, RFLP data confirmed identifications of several other wood associated fungi. One of our ultimate goals is to establish a web-based database of wood basidiomycetes and wood-associated fungi emphasizing ITS sequence and RFLP pattern data plus morphological characteristics in one searchable system. These databases will be able to provide sensitive and reliable identifications of the wood decay community and important wood decay fungal species.
S V Diehl, T C McElroy, M L Prewitt

Physiological properties of fungal test strains according to the European Standard EN 113
1986 - IRG/WP 2258
For the discussion of the European standard EN 113 the EMPA&apos;s procedure of culturing the test fungi and the corresponding virulence of the test fungi as well as the wood moisture content at the end of the test are shown. It is mainly shown that within the standard the choice of the solvent may not be left at the test lab if reproducible results shall be obtained. The different solvents influence in different form the wood decomposition values due to fungal attack. A water leaching of the wood specimen impregnated with solvents generally Further increases the negative effect of the solvent on the fungi. It is therefore the task of the Technical Committee of the European Committee for Standardization (CEN/TC3B) to agree to a standard solvent and to evaluate this in the original state as well as after a leaching followed by uniform drying periods by means of an interlaboratory test.
E Graf, B Zgraggen, P Manser

The influence of timber species and preservative treatment on spore germination of some wood-destroying Basidiomycetes
1988 - IRG/WP 2300
Basidiospores from six wood decay fungi exhibited varying germination rates on untreated softwood and hardwood blocks. Germination inhibition of all test fungi was recorded on pine sapwood. No preference for a certain timber species by a particular fungus was evident. Whereas almost complete inhibition of germination occurred on wood treated with a quarternary-ammonium based wood preservative, most fungi germinated successfully on wood treated with a boron based preservative. Further work is necessary to determine whether a reliable preservative screening using spore germination tests as criteria can be developed.
B M Hegarty, G Buchwald

Why don't more people work with Serpula lacrymans nowadays? A discussion of some of the different approaches to experimenting with this unique fungus
1989 - IRG/WP 1383
Remarkably few laboratories are currently investigating this well-known fungus. Not only has it failed to gain acceptance as a standard test organism (for wood preservative evaluation) in many countries, but is also sometimes excluded from pure research studies when it ought to be an obvious first choice as a representative basidiomycete. This paper discusses some different approaches that have been/are being used by various workers. It is hoped that more workers will be encouraged to look at this fungus as a result of the efforts of this mini-symposium on the dry rot problem.
J D Thornton

Characterization and differentiation of wood rotting fungi by protein and enzyme patterns
1999 - IRG/WP 99-20177
Standardized tests for wood preservatives are performed with defined fungal strains to ensure comparability between laboratories. However, changes of virulence and variation of results are well known events. Suitable and reliable measures to control the stability of the test organisms are necessary.Comparison of protein patterns produced by SDS-electrophoresis was already described by several authors as a possible way to identify and to characterize fungal species and strains, i.e. for Serpula, Coniophora and Poria. We compared protein patterns of several strains of Antrodia vaillantii, Poria placenta, Gloeophyllum trabeum, Lentinus lepideus, and Coniophora puteana. Isoelectric focussing and detection of esterase isoenzymes proved to be an alternative method. The investigations resulted in species-specific protein and enzyme patterns. By comparing the strains of single species it was possible to form groups with similar patterns. Possible misidentifications could be detected. The described methods will be further developed and used to follow possible changes in our test strains.
U Schoknecht

Identification and inhibitory effect of volatiles from different ages of a Trichoderma aureoviride culture on selected wood decay fungi.
1995 - IRG/WP 95-10110
The ability of a Trichoderma sp. to produce volatile organic compounds (VOCs) over a four week period of growth was examined and the inhibitory effect of these volatiles against four selected basidiomycetes over the same period was assessed. After trapping, on tubes filled with chromatography packing material, VOCs were analysed on an integrated automated thermal desorbtion mass spectrometer system. A total of 72 separately identified compounds were recovered although production of any single compound was time dependant. The inhibitory effect of the VOCs against the four basidiomycetes varied dependant on the age of the Trichoderma culture. Highest levels of inhibition being produced by cultures which were 1-2 weeks old at which time 85% inhibition of Neolentinus lepideus was recorded. It was noticeable that highest levels of inhibition of the basidiomycetes was associated with a major shift in the profile of VOCs produced at that time. The potential exploitation of VOC production by Trichoderma isolates for the biological control of decay in wooden structures is briefly discussed.
A Bruce, A Kundzewicz, R E Wheatley

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