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Reporting minutes of the Plenary Meeting 2016
2016 - IRG/WP 16-60409
IRG Secretariat

An Open Letter to Proponents of CLT/Massive Timber
2016 - IRG/WP 16-40755
We present an Open Letter that discusses the need to address the potential for biodeterioration in CLT/Massive timber structure. We invite members to review and sign the document. We also welcome suggestions for potential recipients.
A Taylor, J Lloyd, T Shelton

International Directory of Members and Sponsors 2016
2016 - IRG/WP 16-60392
IRG Secretariat

Guidelines for “Gareth Williams Award”
2016 - IRG/WP 16-60393
IRG Secretariat

Guidelines for “Richard J Ziobro Award”
2016 - IRG/WP 16-60394
IRG Secretariat

Annual Report 2015
2016 - IRG/WP 16-60395
IRG Secretariat

Agenda 2016 Plenary meeting
2016 - IRG/WP 16-60396
IRG Secretariat

The 47th Annual Meeting of IRG. Poster abstracts
2016 - IRG/WP 16-60397
IRG Secretariat

Programme. The 47th Annual Meeting of The International Research Group in Wood Protection
2016 - IRG/WP 16-60398
IRG Secretariat

IRG Documents 2016
2016 - IRG/WP 16-60410
IRG Secretariat

Evaluating the Effects of Post Dip-Treatment Laser Marking on Resistance to Feeding by Subterranean Termites
2016 - IRG/WP 16-10854
Dip-treatment of wood packing materials is often used instead of pressure treatment mainly because of issues relating to simplicity and cost. Packaging boxes fabricated for the United States Army are required to be dip-treated for at least one minute in an approved preservative solution prior to use. These boxes are expected to have a service life of up to 20 years in a wide variety of environments. Recently, there is interest in using laser markings on these boxes, which can result in a breach of the preservative shell, potentially increasing susceptibility of the wood to termites and decay. Alternatively, thermal modification of the wood by the laser may be sufficient to protect these marked areas. In this study, solid southern pine wood and two types of plywood samples were dip-treated with copper or azole based preservative formulations. Leached and unleached blocks were then evaluated using modified AWPA testing methods to determine if laser marking increased susceptibility to feeding by subterranean termites. Termites preferentially fed within the laser marked areas as compared to non-lasered areas of the block. This suggests that laser marking is a breach of preservative treatment and has the potential to strongly affect the long-term durability of these containment boxes where there is termite pressure. However, when unleached-lasered samples were compared to leached-non-lasered samples, termites showed a stronger preference for feeding on the non-lasered surfaces of leached blocks and the laser marked areas of unleached blocks, indicating that leaching, rather than laser marking, may have more of an effect on termite feeding preference. Results from this study will be used in development of new methods addressing long-term labelling protocols for dip-treated wood packing materials.
R A Arango, B Woodward, S Lebow

Above-ground performance of a buffered amine oxide treatment system against Mastotermes darwiniensis
2016 - IRG/WP 16-10855
Above-ground H2 field tests against Mastotermes darwiniensis were conducted in far north Queensland to assess the efficacy of buffered amine oxide treatments in the softwoods Pinus sylvestris and P. radiata, and the hardwoods Eucalyptus regnans and E. diversicolor. Untreated hardwoods and slash pine bait wood (P. elliottii) were severely attacked or destroyed, while untreated P. sylvestris was moderately to heavily attacked and untreated P. radiata only light-moderately attacked probably due to its high heartwood content. In softwoods, the H2 (permethrin) and H3 (Cu Quat) buffered amine oxide treatments were more effective than comparative H2F and H3 LOSP treatments. Nevertheless, as test blocks were cut after treatment from longer lengths, all treatments had some replicates with holes often penetrating deeply from the ends, indicating treatment breach against this most voracious of termite species. Unlike the softwood trial, hardwood test blocks were treated in final form and any damage that occurred was from the sides. All H2 buffered amine oxide treated hardwood blocks were sound, while some damage occurred in other treatments.
L J Cookson, R W Clawson Jr

Antitermitic activities of Shisham (Dalbergia sissoo Roxb.) heartwood extractives against two termite species
2016 - IRG/WP 16-10856
Shisham (Dalbergia sissoo) heartwood extractives were investigated for antitermitic activities against Heterotermes indicola and Reticulitermes flavipes. Heartwood extractives were removed from wood shavings by soxhlet extraction using (2:1) ethanol: toluene as the solvent system. Filter paper bioassays were conducted against both species to observe concentration dependent feeding response and mortality of termites. Results indicated that the highest termite mortality occurred at 10 mg/ml with a LC50 at 5.54 and 3.89 mg/ml against H. indicola and R. flavipes, respectively. Shisham extractives showed more repellency and antifeedant activity against H. indicola compared to R. flavipes. In choice and no-choice feeding bioassays with extracted and un-extracted Shisham wood blocks, increased wood loss due to termite feeding was observed on extracted blocks compared to un-extracted blocks. Higher termite mortality was also observed after feeding on un-extracted blocks compared to extracted blocks. Results also showed that extractives from Shisham imparted resistance to vacuum-pressure treated Southern pine (SYP, Pinus taeda L.) and Cottonwood (CW, Populus deltoides) against both species. These results suggest that Shisham extractives have antitermitic properties and may be potentially useful in the development of environment friendly termiticides.
B Hassan, M Mankowski, G Kirker, S Ahmed, M Misbah ul Haq

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan
2016 - IRG/WP 16-10857
Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, Reticulitermes flavipes from four wood species from Pakistan (Dalbergia sissoo, Cedrus deodara, Morus alba and Pinus roxburghii) as well as Teak (Tectona grandis). Termites showed increasing levels of mortality with increasing concentration of heartwood extractive when exposed to extractive treated non-durable southern yellow pine (SYP) blocks in a force feeding test compared to SYP blocks treated with water or solvent (ethanol: toluene) only. Characterizations of heartwood extractives were performed using Gas Chromatography-Mass spectrometry (GC-MS). Chemical profiles were prepared for each wood species’ extractives and are discussed relevant to their termiticidal properties. Future work will focus on further isolation of bioactive compounds or synergistic groupages of bioactive compounds from these and other wood species for use as environmentally friendly insecticides/termiticides for wood and wood based materials.
M E Mankowski, B Boyd, B Hassan, G T Kirker

Foundation piles: analysis of beech wood decay in service life conditions
2016 - IRG/WP 16-10858
Wood piles foundation system was largely used over decades. Thus, numerous buildings over the world are based on this constructive system. In the context of reduction of CO2 emissions in the building field of constructions, substitution of concrete by wood as material for foundation piles seems to be a promising alternative. However, fluctuation of the water table level in soil may promote fungal decay of the wood foundation piles in service. Thus, wood used as foundation pile was often treated with high toxicity chemical products. To promote the use of wood in pile foundation on the basis on its natural durability, diagnostic and prediction methodology of the wood decay needed to be improved. Mesocosm decaying experiments were carried out on beech wood mini-stakes. Influence of a water gradient occurring in wood on its strength loss was evaluated. Compression parallel to the grain (fc,o), fungal colonization of wood, near infrared spectroscopy and enzymatic activities measurements were used to decipher wood decay. However, none of these factors was fully accurate when considered alone. Indeed, degradation pattern seemed to be patchy due to high heterogeneity of the wood and repartition of microorganisms in soil. It turned out that no optimal correlation could be found after an one factor analysis. At the contrary, multivariate analysis allowed an accurate clustering of the wood samples. This approach discriminated between samples with identical fc,o value but that differed by their enzymatic activities and cell wall polymer contents. Finally, a predictive model of the fc,o was built. The model had the potential to predict the fc,o of a wood foundation pile from on-site measurements. Relative part of the enzymatic activity in the wood decay dynamic is also discussed.
Q Kleindienst, A Besserer, M-L Antoine, C Perrin, J-F Bocquet, L Bléron

The copper-transporting ATPase pump and its potential role in copper-tolerance
2016 - IRG/WP 16-10859
Copper-tolerant brown-rot decay fungi exploit intricate mechanisms to neutralize the efficacy of copper-containing preservative formulations. The production and accumulation of oxalate is the most widely recognized theory regarding the mechanism of copper-tolerance in these fungi. The role of oxalate, however, may be only one part of a series of necessary components required for this complex mechanism. Annotation of the Fibroporia radiculosa genes involved in copper-tolerance characterized a subset of proteins, three copper-transporting ATPase pumps, which regulate copper concentrations inside the fungal cell by exporting excess copper ions. The goal of this study was to determine the relevance of copper-transporting ATPase pumps in the mechanism of F. radiculosa copper-tolerance. Southern pine test blocks were pressure-treated with 0.6%, 1.2%, and 2.4% ammoniacal copper citrate and subjected to a copper-tolerant strain of F. radiculosa and a copper-sensitive strain of Gloeophyllum trabeum in decay tests over a four week period. Untreated Southern pine test blocks subjected to both test fungi served as controls. Expression levels of three copper-transporting ATPase pumps were evaluated each week by qRT-PCR. F. radiculosa showed up-regulation of all three ATPase pumps when exposed to the copper treatments over the course of this study. G. trabeum showed down-regulation of ATPase1 and ATPase2 and no expression of ATPase3 when exposed to the copper treatments over the course of this study. Up-regulation of the three ATPase pumps can be correlated to the ability of F. radiculosa to decay copper-treated wood (12% weight loss at week 4). Down-regulation of ATPase1 and ATPase2 and lack of ATPase3 expression can be correlated to the inability of G. trabeum to decay copper-treated wood (1% weight loss at week 4). Preliminary results indicate these three ATPase pumps function as an essential component of the complex mechanism of copper-tolerance utilized by F. radiculosa.
K M Ohno, C A Clausen, F Green III, G Stanosz

Production of reactive oxygen species in the presence of oxidized iron and oxalate under conditions mimicking brown-rot fungal degradation of wood
2016 - IRG/WP 16-10861
The biochemical role of oxalate in the fungal solubilization of iron is well known, but additional information is needed on the role that oxalate plays in the brown-rot decay of lignocellulose. In this study iron sequestration from iron and iron oxide-hydroxides was assessed with regard to the function of a chelator-mediated Fenton (CMF) reaction and the generation of reactive oxygen species (ROS). The reactions conducted at the lowest pH condition (pH 2.0) and oxalate concentration (15μM) generated the greatest amount of FeII, suggesting that pH, rather than oxalate concentration may have a greater impact on Fenton reactions, and specifically the CMF reaction. Moreover, iron oxide-hydroxides that were pre-incubated with oxalate prior to the CMF reaction, generated more ROS than the iron oxide-hydroxides without oxalate incubation. This indicates that an enhanced CMF reaction was promoted by iron sequestration due to oxalate incubation, and also supports previous research showing a pH-dependent iron transfer from oxalate to chelators produced by fungi. Although Fenton reactions were enhanced at low pH, the iron transfer reaction was enhanced at higher pH. In a decay environment, this would limit damaging Fenton reactions from occurring in the low pH environment directly surrounding the fungal hyphae.
Yuan Zhu, Liangpeng Zhuang, B Goodell, Jinzhen Cao, J Mahaney

High-frequency monitoring of mass loss due to brown rot degradation of modified wood
2016 - IRG/WP 16-10862
Fungi growing in liquid culture undergoes three separate phases in which they i) adapt to the new environment, ii) grow unrestrictedly and exponentially, and iii) are inhibited to increase in number/mass due to lack of nutrients etc. Filamentous fungi have been shown to exhibit similar growth phases in a solid food substrate and have been modelled to grow in this way also in solid wood. In modified wood with high treatment levels, fungi cause no or little mass loss but the reason for this has not been fully explained. To be able to predict the service-life of modified wood, understanding the growth pattern of wood degrading fungi in these materials may be important. The aim of this study was to find out whether brown rot fungi undergoes the same growth phases in solid wood as in liquid culture and study the growth pattern of brown rot fungi in modified wood. This was done through high-frequent monitoring of mass loss over 300 days of exposure of acetylated and furfurylated wood to Postia placenta. Mass loss results of the untreated wood indicated clearly that the fungi in this material go through phases similar to phases seen in liquid cultures. However, the results for the modified wood materials were less clear. Little mass loss and a degradation rate 100 times lower than in the untreated wood during exponential growth may suggest that the fungi in the modified wood samples were still adapting to the new environment. On the other hand, the fact that mass was lost at all suggests that degradation did occur and that the fungi were growing exponentially.
R Ringman, A Pilgård, K Richter

Susceptibility of wood substrates to Aurebasidium pullulans at different temperatures
2016 - IRG/WP 16-10863
There is an increasing awareness of how the aesthetical performance of wood exposed outdoors changes over time and especially in the first few years after installation. Mould and blue stain fungi are biological agents that contribute to the weather grey colour on a wooden façade, and the blue stain fungi Aureobasidium pullulans is commonly identified as colonizer on coated and uncoated wood exposed outdoors. In this study 21 wood substrates (untreated, preservative treated and modified) were tested for their susceptibility to A. pullulans when incubated at three different temperatures (11, 16 and 22°C). Western red cedar and preservative treated wood had the lowest mould ratings at the end of the test period (84 days). Alder, ash, Norway spruce and Sitka spruce reached maximum rating already at day 28, and at day 84 also aspen, European larch, thermally modified pine, birch, acetylated pine and DMDHEU modified pine had reached maximum rating. Incubation temperature had a significant influence on the growth of A. pullulans throughout the test period for acetylated and DMDHEU modified samples – and generally the modified wood substrates were more sensitive to changes in temperature than the other tested substrates. Scots pine sapwood seemed to be less susceptible to A. pullulans in mono cultures, demonstrating low mould ratings throughout the test period. This contradicts to previous studies were Scots pine sapwood tended to have high susceptibility when using a mix of mould and blue stain fungi.
L Ross Gobakken, G Alfredsen

Formation of biofinishes on outdoor exposed wood; the impact of wood-oil combination and geographical location
2016 - IRG/WP 16-10864
Growth of dark moulds enables the use of a decorative and protective biofinish for wood, showing advantages compared to traditional wood-coatings in terms of sustainability and self-repair. Based on the formation of a uniform mould covering on oil treated wood during outdoor exposure, the utilisation of a biofinish is in development. Basic information is lacking on the correlation between exposure site and biofinish formation on wood. To evaluate the impact of different locations, a biofinish assessment method was applied on different combinations of wood species and vegetable oil types after outdoor exposure in the Netherlands and Norway. Biofinishes were detected on wood samples made of spruce, pine sapwood and ilomba that were treated with olive oil and on pine sapwood treated with raw linseed oil after one and a half year of outdoor exposure in the Netherlands. More time was needed for biofinish formation on multiple wood-oil combinations for samples exposed in Norway. After two years of outdoor exposure three out of five wood-oil combinations that contained biofinishes in the Netherlands, showed similar results with the samples in Norway. Biofinish formation was not detected at all on untreated wood samples, regardless the wood species or exposure site. Loose fibres were observed on the surface of all untreated samples. It is likely that biofinish formation was prevented by the removal of stained fibres. Analysis of the stain coverage development on the wood samples, including initial stages of biofinish formation, showed a significant effect of exposure time and (oil) treatment on the stain coverage.
E J van Nieuwenhuijzen, L Ross Gobakken, M F Sailer, R A Samson, O C G Adan

Fungicidal Effect of Tobacco Stalks (Nicotiana tabacum L.) Against Brown Rot Fungi “Coniophora puteana”
2016 - IRG/WP 16-10865
In this study it was investigated that the fungicidal effect of tobacco plant (Nicotiana tabacum L.), which is grown in many countries of the world, against brown rot fungi “Coniophora puteana”. The protective effect of this plant on Scotch pine (Pinus sylvestris L.) wood was considered by means of fungi decay test (EN 113). The wood samples have been treated by five different extracts; at 3%, 5%, 10%, 15% and 20 % concentrations. As a result of the study it was found that the retention values increased with increasing the concentration of the Tobacco plant, in all variations. Weight losses of all test samples were lower than untreated samples. The best performance was obtained from the variation in 15 % concentration. However, tabocca plant has been found not efficient enough to protect the wood against fungi decay (Coniophora puteana) according to the European norms.
Ü C Yıldız, S Yıldız, A Yılmaz, S Durmaz

New approach to improve the estimation of colony population in subterranean termites (Blattodea: Rhinotermitidae)
2016 - IRG/WP 16-10866
The aim of this study was to estimate the mortality and fading effects of dye markers Neutral red and Nile blue commonly used in the estimation of termite colony population, in order to determine the decrease rate from the initial number of marked and released termites. This rate can be considered in the application of the different indexes used to calculate the number of termites of the colony. In the laboratory, Reticulitermes grassei Clément, 1977 were forced-fed during four days with Neutral red 0.5% (wt/wt) and Nile blue 0.5% (wt/wt); later the percentage of mortality and fading was recorded after 30, 40, 60, 80 and 137 days post treatment. These allowed us to obtain a fitted linear regression line that can be used for estimating the number of termites that remain marked into the colony at any day. The percentage of mortality observed increased from 3.17% at 30 days to 18.07% at 137 days for the Neutral red dye and from 8.62% at 30 days to 21.89% at 137 days for Nile blue. No fading was observed at 30 and 40 days for Neutral red and until 60 days for Nile blue, but increased from 10.59% at 60 days to 34.68% at 137 days for Neutral red and from 5.94% at 80 days to 12.49% at 137 days for Nile blue. A field estimation of the colony population was made in two colonies from Palenciana town (Córdoba, Spain) using the Lincoln index. The colony population was estimated twice, first considering the total number of marked released termites and later taking into account their decrease (by mortality and fading) in relation with the days elapsed since their release into the colony, estimated with the linear regressions obtained.
E Alcaide, R Molero, J Diz, M Gaju

Real-Time PCR Assays for the detection of the dry rot fungus Serpula lacrymans and its close relative Serpula himantioides
2016 - IRG/WP 16-10867
Prevention of wood decay by fungi of the phylum Basidiomycota is an important issue of wood protection. The most destructive fungus in buildings in Central Europe is the dry rot fungus Serpula lacrymans, which needs more extensive restauration measures than all other wood decay fungi. Its close relative S. himantioides occurs more frequently in outdoor environment. The assessment and remediation of fungal damages require an identification of the infesting species, in particular the proof or exclusion of S. lacrymans. Morphological identification fails, if no fungal structures (fruit bodies, spores, mycelia and strands) with specific characteristics are available. In this case, DNA based methods can be used. For detection of S. lacrymans and S. himantioides a conventional PCR procedure using specific primers from the ITS region (Internal transcribed spacer of nucleus ribosomal DNA) is well established (Schmidt 2009, Jacobs et al. 2011). But, in the analysis of environmental samples, numerous problems arose in recent years. The most important difficulties are the interpretation of equivocal agarose gel findings and additional analysis efforts with small DNA amounts, degraded DNA, or high content of inhibitory substances in the sample material. To overcome these disadvantages of conventional PCR, new diagnostic assays for the detection of S. lacrymans and S. himantiodes were developed. The four different assays are based on real-time PCR, using partially specific primers and species specific TaqMan probes. The assays are targeting two genomic DNA regions, the multi-copy ITS and the single-copy beta-tubulin gene (BET). Thus, the diagnostic findings can be confirmed by two independent detection parameters. It was expected that the high specificity of the TaqMan probe technology prohibits the formation of unspecific byproducts and PCR artifacts. As a result of the work, primers and specific probes were generated from verified reference data of the two target regions. Basic performance parameters of the designed assays were optimized. The experimentally determined limit of detection (LOD) with the ITS targeting assays was 0.5 pg genomic DNA of S. lacrymans or S. himantioides, and with the BET targeting assays 1.0 pg. Out of twenty reference fungi, all six included Serpula strains could be clearly assigned to the appropriate fungus, and no false findings with other fungi were obtained. A first exploratory practice test was done with ten environmental samples, taken from damaged wood. These tests confirmed that the new diagnostic tool is a fast and reliable method for detection of the two Serpula-species. Non-specific reactions, side reactions and the production of PCR artifacts could be eliminated completely. A further considered issue of assay development was the DNA isolation procedure, which is time-consuming and susceptible to both, cross contaminations and loss of small samples. Therefore, direct PCR approaches were tested by processing whole cells from suspended fresh spores as well as milled dry mycelia directly in PCR reactions. It could be shown that pure culture material can be successfully processed in a direct PCR without any prior cell disruption and DNA isolation procedure. With environmental samples, the strategy worked in case of fresh mycelia and fruit bodies but findings were not reliable with decayed wood and aged fungal strands. Further studies are necessary to clarify terms and limits of practical application.
K Jacobs, N Rangno

Exudate production: a detoxification strategy of wood decaying fungi
2016 - IRG/WP 16-10868
Even often observed, the exudate production in fungi remains mainly unstudied. During growth on oak wood, the white-rot fungus Trametes versicolor produces droplets of a red-brown liquid, this phenomenom being observed with nine studied strains. One of these strains secretes a similar exudate on rich medium even in the absence of wood. This secretion seems to be linked to the formation of special fungal structures involved in the production of extracellular enzymes. A proteomic study revealed that the protein content of the exudate is indeed closely related to extracellular enzymatic systems secreted by Trametes versicolor during oak degradation. It contains in particular enzymes involved in aromatic compounds oxidation such as Dye peroxidase, versatile and manganese peroxidases and also various carbohydrate-active enzymes. The proteomic studies revealed also the presence of a detoxification system involving glutathione related systems. In addition, a transcriptomic approach showed that this process is linked to induction of genes involved in intracellular degradation and detoxification of wood extractives and reactive oxygen species. From these observations, we propose that such exudate production by pioneer wood colonizers such as Trametes versicolor could be a way for facilitating extraction, concentration and degradation of wood extractives and other potential toxic by-products produced during the wood degradation oxidative process.
A Deroy, J G Berrin, S Dumarçay, P Gérardin, A Kohler, D Navarro, C Rose, R Sormani, M Morel-Rouhier, E Gelhaye

Durability to decay organisms of Pinus nigra subsp. laricio var. corsicana. Influence of the moon phase
2016 - IRG/WP 16-10869
Actually the use of wood has an added value since it is a renewable, biodegradable and recyclable material. For this reason, the evaluation of it natural durability is essential when establishing the level of protection required, being depending on the designated end use of timber. On the other hand, there is a popular belief based on the influence of the moon phase in felling timber, recommending the waning moon as the optimum for felling trees. The aim of this work was to study the resistance of Pinus nigra subsp. laricio var. corsicana to be decayed by brown and white-rot Basidiomycetes (Coniophora puteana (Schumacher ex Fries) Karsten and Postia placenta (Fries) sensu Cooke J. Eriksson) and termites (Reticulitermes grassei Clément). In the same way has been evaluated the possible influence of felling during the waxing and waning moon phases, on the durability. Durability is established applying the European Standards CEN / TS 15083-1 for Basydiomycetes and EN-117 for termites. The results show that this species is not durable against the fungi studied and termites, and there is not significant differences between the two moon phases. The only differences have been found in the reference wood of Pinus sylvestris, where the obtained results advice to cut the trees better in waxing than in waning moon phase.
M T Troya, M Conde, M J Barriola, F Llinares, V Dorronsoro

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