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Distinguishing isolates of Aureobasidium on the basis of their ability to utilise lignin breakdown products as a sole carbon source
1996 - IRG/WP 96-10151
Wild isolates of Aureobasidium were obtained by dilution plating from a ca 20 year old painted pine window frame. Four isolates were obtained from the paint/wood interface region and four isolated from regions deep in the wood. The isolates were then used to inoculate liquid cultures containing ferulic acid, a lignin breakdown product, present as the sole carbon source. Ability of the isolates to use ferulate, judged by fungal yield, viable propagule count and absorbance at 280 nm (a measure of the aromatic's final concentration) was dependent on the site of isolation. Isolates from the paint/wood interface were consistently better at utilising ferulate than those isolated from deep in the wood and a possible reason for this is suggested.
M W Schoeman, D J Dickinson

Extracellular mucilage (ECM) in wood decay basidiomycetes
2002 - IRG/WP 02-10439
The ability of wood decay basidiomycetes to produce extracellular mucilage (ECM) and its relationship with total biomass production is being investigated. Growth and ECM production by the brown-rot fungus Gloeophyllum trabeum (FPRL 108 N) and the white-rot fungus Coriolus versicolor (CTB 863 A) was assessed in liquid culture under different conditions and in the presence of the fungicide cyproconazole. The production of biomass in G. trabeum was significantly influenced by the carbon source, monosaccharides stimulating increased biomass compared with oligosaccharides and polyols. The nitrogen source also significantly affected biomass production, with arginine and L-glutamic acid supporting maximum biomass. The best temperature for growth was 30°C, lower temperature causing a significant reduction in biomass production. The pH optimum for maximum growth was found to be 4.0. ECM production was influenced significantly by the nitrogen source, as well as by the pH of the medium and the temperature of incubation. The greatest proportion of ECM in the total biomass was produced by cultures incubated at 10°C (27% of the total biomass) and at pH 5.0 (16% of the total biomass). The same factors that affected the production of biomass and ECM in G. trabeum, also significantly affected C. versicolor. Again, simple monosaccharides supported the best growth. Amongst the nitrogen sources tested, L-glutamic acid stimulated maximum biomass production (double that of any other nitrogen source tested) whereas the greatest proportion of ECM in the total biomass was produced with arginine and isoleucine as nitrogen sources. The optimal temperature for growth was 22° C, whilst the optimum pH was 5.0. At 10°C the greatest proportion of ECM was produced, which represented about 24% of the total biomass. In terms of pH effects, the greatest proportion of ECM was produced at pH 6.0. The introduction of cyproconazole significantly reduced the amount of biomass produced by both organisms as expected. However, the production of ECM in both species was also affected greatly by the presence of biocide, with the proportion of ECM in the total biomass increasing significantly as the concentration of cyproconazole was raised. The results are discussed with regard to the possible role(s) of ECM in the decay process and its interaction with a specific organic preservative.
D Vesentini, D J Dickinson, R J Murphy

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

Preliminary study of the fungicidal and structural variability in copper naphthenates and naphthenic acids
1996 - IRG/WP 96-30114
Copper naphthenates, an oil-borne wood preservative listed by the American Wood-Preservers' Association (AWPA), is manufactured by complexing copper(II) with naphthenic acids. Prior to AWPA listing as a wood preservative, field experiments showed that copper naphthenates generally had good stability and were active against wood-destroying organisms. Recently, however, there have been reports of some copper naphthenate-treated poles rapidly failing. One possible explanation for the varying effectiveness could be that the structure, and resulting biological activity, of the naphthenic acids used to make copper naphthenate may vary. To test this hypothesis several naphthenic acids and copper naphenates were obtained and their fungicidal activity against three wood-destroying fungi measured. In addition, the chemical structure of the naphthenic acids were examined by proton- and carbon- NMR. Different activities were observed, especially against a copper-tolerant fungus. Some apparent correlations were seen between the fungicidal activity and chemical structures for the few samples studied.
T Schultz, D D Nicholas, L L Ingram Jr, T H Fisher

Respiration methods used to follow the decay of wood and the toximetric evaluation of wood preservatives
1975 - IRG/WP 249
When wood is attacked and decayed by fungi, wood substance and oxygen (02) are consumed, while carbon dioxide (CO2), water and heat are liberated. Early in the 1960's workers from England, Canada and Sweden began studying CO2 evolution, with respect to decay and its control using chemical preservatives, while in Germany and the USA O2 utilization was being similarly examined. Oxygen consumption measurements during the decay of wood were made mainly using pressure differential closed systems and were shown to be reasonably sensitive and a suitable reflection of the rate and extent of decay. Carbon dioxide measurements were made using titration, conductivity and gas-chromatographic methods. The last method appears to be the most useful, being applicable to open and closed systems, flexible in application, very sensitive over a thousand-fold concentration range change without switching, and easily automated. Its application to evaluating the toxicity of wood preservatives has been intensively studied and shown to give chemical toxic thresholds after only one third of the normal incubation time, which are similar to those based on the much longer conventional weight loss method.
R S Smith

Temperature influence on the growing velocity and cellulolytic activities of Poria placenta strains from several locations
1986 - IRG/WP 2263
The differences observed on the FPRL 280 Poria Placenta strain at several Research European Laboratories for determining up the fungicide effectiveness of wood preservative has carry us to do a comparative study about the cellulolytic activity and growth velocity of each of this strains at different temperatures (22, 24 and 28°C). The results show significative differences when the temperature is changed.
A M Navarrete, M T De Troya

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

Virulence testing of cultures of different origins of the test fungus Coriolus versicolor strain CTB 863 A
1986 - IRG/WP 2267
The virulence of cultures of different origins of Coriolus versicolor CTB 863 A - a strain which is mentioned in EN 113 - was tested. Standard blocks of beech wood were used at temperatures of 20-22°C and 26-28°C and particleboard was tested at 26-28°C. The decay capacity of the different inoculations varied widely, as could be expected it was greatest at the higher temperature level.
W Kerner

An insight into brown rot decay of timber as revealed by 13C CP/MAS NMR
1985 - IRG/WP 1259
L E Leightley

Effect of fatty acid removal on treatability of Douglas-fir
1993 - IRG/WP 93-40008
Treatment of Douglas-fir with chromated-copper-arsenate (CCA) poses a major challenge. Several hypotheses based on the anatomical aspects as well as chemical reactivity of the preservative formulations with cell wall constituents and deposits have been proposed. Techniques to prevent pit aspiration or slow fixation reactions have, however, not significantly improved treatment. The presence of high molecular weight fatty acids have been reported to be responsible for higher hydrophobicity in some wood species. These acids can react with Cu+2/Cr+3 ions to form insoluble metallic soaps, thereby immobilizing Cu/Cr and increasing wood hydrophobicity by a mechanism similar to that employed in paper sizing. The effect of fatty acids on treatability was explored by removing these components via several extraction methods. In general, extracted wood had higher gross solution absorptions and chemical retentions, but preservative penetration was largely unaffected. The results suggest that removal or disruption of fatty acids can improve treatability of Douglas-fir heartwood.
S Kumar, J J Morrell

The use of C CP/MAS NMR in the chemical identification of decayed and undecayed, tropical timber species
1984 - IRG/WP 1224
13C CP/MAS NMR was found to be an extremely powerful tool for elucidating the chemical composition of Eucalyptus maculata, Pinus elliottii and Alstonia scholaris. The differences in lignin composition were different for each timber and discussed in relation to decay caused by soft-rot and white rot fungi. In particular the presence of syringyl and guaiacyl lignin types are discussed.
L E Leightley

The effect of selective additives and conditions on the decomposition of Basamid in Douglas fir heartwood
1992 - IRG/WP 92-3698
Basamid is a solid, powdered chemical used as an agricultural soil fumigant. Decomposition of Basamid isothiocyanate, hydrogen sulfide, methyl amine, and formaldehyde. Basamid has some potential as a wood fumigant, but it decomposes too slowly to be effective. Various additives and conditions were tested for their ability to enhance Basamid decomposition in Douglas-fir heartwood. Higher MC's and temperature, as well as copper sulfate and powdered pH 12 buffer increased decomposition rates with copper increasing the efficiency of breakdown to form MITC.
P G Forsyth, J J Morrell

The distribution of introduced acetyl groups and a linseed oil model substance in wood examined by microautoradiography and ESEM
2000 - IRG/WP 00-40169
Microautoradiography, a photographic method that shows the localization of substances labelled with radioactive isotope, and Environmental Scanning Electron Microscopy (ESEM) were combined to enhance sensitivity, resolution and reliability for examination of the distribution of introduced substances in wood. The preparation of microautoradiographs is less complicated when investigated with ESEM and the preparation of ESEM-samples is quick and easy compared to a conventional SEM. When investigating microautoradiographs with ESEM, the wood structure is observed underneath the almost transparent photographic film. Silver grains, indicating the location of studied substances, are clearly distinguish from the wood material. The technique was used in two case studies for examination of cell wall penetration and distribution in pine sapwood. The distribution of acetyl groups, introduced by acetylation with acetic anhydride, and the distribution of a linseed oil model substance, triglycerol trioleate, were examined. Examinations of introduced acetyl groups showed an even distribution of acetyl groups in the wood cell wall at acetylation level of about 5, 15 and 20% (weight gain). Examination of the linseed oil model substance, glycerol trioleate, showed the presence of the model substance on applied surfaces, in rays and in lumen of some latewood cells. No cell wall penetration was observed.
M Rosenqvist

Distribution of cellulases in the body of Coptotermes formosanus and the probability that the termite uses glucose as an energy and carbon sources
1997 - IRG/WP 97-10202
We assayed extracts of the digestive system and of the whole body of Coptotermes formosanus to determine where the various cellulases, glucose, and related substances were concentrated and to detect pyruvate dehydrogenase activity in the hindgut-removed body in order to verify its full cellulolytic system. About 20%, 18% and 36% of the total exo-1,4-ß-glucanase activity of C. formosanus were detected in the salivary glands, midgut, and hindgut, respectively. About a third of the total endo-1,4-ß-glucanase activity in the termite was detected in the salivary glands (34.5%) whereas the activities in the midgut and hindgut were 21.1% and 18.2%, respectively. About 75% of the total ß-D-glucosidase activity in the termite was detected in the midgut. Thus all the necessary cellulases for hydrolysis of natural cellulose to glucose were present in the region ranging from the salivary glands to the midgut in significant amounts. Most of the glucose and trehalose detected in the termite existed in the gutted-body. Most of the glucose detected in the gut existed in the midgut. Pyruvic acid was directly converted to acetyl-CoA in the presence of NAD+ by a crude extract of the gutted-body. These results suggest that natural cellulose ingested by the termite is hydrolyzed to oligosaccharides in the region of the foregut and midgut as well as in the hindgut, that oligosaccharides are hydrolyzed to glucose predominantly in the midgut, and that the resultant glucose is absorbed through the midgut wall into the tissues to be used as important energy and carbon sources.
S Itakura, H Tanaka, A Enoki

The chemical analysis and biological evaluation of wood extractives as potential timber preservatives
1995 - IRG/WP 95-30090
Work involved the biological performance of water and organic solvent soluble extractives of four naturally durable wood species, namely; Matumi, Tamboti, Sneezewood and the Turpentine tree. These timber species are known to be naturally durable against termites and fungi (±25 to 35 years). The extractives were evaluated against termites and fungi using impregnated pine pencil stakes in field tests and soil burial trials over a 2 year period. C13NMR analysis of extractives isolated from the wood was carried out to try and identify the key chemical components which might impart durability with a view to prediction of new potential wood preservative formulations.
P Turner, D Conradie

Bending properties of TCMTB-treated Southern pine sapwood using supercritical carbon dioxide impregnation process
1997 - IRG/WP 97-40080
The effects of elevated pressure and treatment with thiocyanomethylthiobenzothiazole (TCMTB) on the bending properties of Southern pine sapwood were evaluated at pressures ranging from 1,800 to 3,600 psi. All bending properties were affected to some extent by supercritical fluid treatment. Modulus of elasticity and work to maximum load were not significantly affected by pressure levels. Modulus of rupture differed among individual pressure levels, but the effects on bending strength were less definitive. TCMTB retention had little or no effect on properties, suggesting a lack of chemical interactions between the lignocellulosic matrix and this biocide. The effect of treatment on bending properties was unexpected as previous trials on smaller specimens and selected composite panels had shown no negative effects. Further trials of other wood samples with increased replication are planned to more fully understand potential treatment effects on strength properties.
Gyu-Hyeok Kim, S Kumar, E S Demessie, K L Levien, J J Morrell

Case histories involving attempts at identifying infestations, determining the source and controlling the Formosan subterranean termite in Atlanta, Georgia USA
2000 - IRG/WP 00-10342
The University of Georgia Department of Entomology and the Georgia State Department of Agriculture have been involved in identifying and working with Pest Control Operators and homeowners dealing with Formosan subterranean termite infestations in the Atlanta, Georgia metropolitan area since 1993. Our involvement with seven separate infestations is outlined in this paper in the form of case histories to highlight the need for the development of community-based action plans to deal with the inevitable introduction of this economically important insect pest to other non-endemic areas.
B T Forschler, J Harron, T M Jenkins

Wood extractives as carbon sources for staining fungi in the sapwood of lodgepole pine and trembling aspen
1995 - IRG/WP 95-10098
Wood discoloration by sapstaining fungi reduces lumber value. In Canada, the most commonly recorded sapstaining fungi belong to the genera Ophiostoma. This work evaluated the effect that Ophiostoma piceae, Ophiostoma ainoae, and Ophiostoma piliferum used the lipids present in the sapwood of lodgepole pine (Pinus contorta Dougl.) and trembling aspen (Populus tremuloides Michx.). Wood lipids, commonly known as extractives, consist mainly of triglycerides, fatty acids, resin acids, sterols, steryl esters and waxes. The sapwood of lodgepole pine and trembling aspen was rich in triglycerides. All the sapstaining fungi tested were able to degrade the triglycerides in both of the wood species very effectively. The fatty acids, steryl esters and waxes were used slowly, especially in lodgepole pine. The fungi could also decrease the level of resin acids in lodgepole pine.
Yong Gao, C Breuil

Termite Field Tests of Various Timber Species Treated with permethrin using supercritical carbon dioxide
2005 - IRG/WP 05-10560
Termite field tests were conducted on permethrin-treated Eucalyptus obliqua heartwood, Pinus radiata sapwood and P. radiata LVL. The permethrin was impregnated using either supercritical carbon dioxide (scCO2) or light organic solvent preservative (LOSP) systems. Comparative permethrin retentions were most accurately achieved in P. radiata sapwood, where no difference between impregnation systems was found in performance against Coptotermes acinaciformis, and a minor difference in favour of scCO2 was found against Mastotermes darwiniensis. P. radiata LVL specimens treated using scCO2 performed slightly better than those impregnated with LOSP, reflecting slightly higher permethrin uptakes in the former. E. obliqua heartwood was completely destroyed by M. darwiniensis when impregnated with LOSP but was mostly sound when scCO2 was used, suggesting improved uniformity of penetration by the latter treatment.
A Qader, L J Cookson, J W Creffield, D Scown

Utilization of nitrogenous substance by Serpula lacrymans
1989 - IRG/WP 1397
When Serpula lacrymans degrades wood, the fungus is considered to have to assimilate nitrogen, which is not abundant in the wood, from the third material. The strands/mycelium has grown into the soil under the floor of the wooden house damaged by the dry rot fungus. The authors analyzed the soil samples collected from the ground under the floors of the dryrotted houses. The samples which were collected from the ground covered with the strands/ mycelium of the fungus contained less quantity of nitrogen than the ones from the ground not covered with them.
S Doi, I Togashi

Cellular and fractural failure after supercritical fluid impregnation of four wood species
2004 - IRG/WP 04-10503
Supercritical fluids (SCFs) have been investigated for delivering biocides into sawn wood. Pressure differentials during treatment may exceed the compressive or tensile strength perpendicular to grain, creating a potential for transverse deformations that exceed elastic strain limits. Wood treated by SCF processing with CO2, a potential biocide carrier, was inspected macroscopically and microscopically. Both cell wall damage and smooth fracture surfaces appeared in the cellular structure. Damage was related to the rates of pressurization and venting and appeared to be species-specific. Cell walls were damaged during pressurization, whereas fracture damage occurred during venting. Specimen dimensions, permeability and anatomical structure are critical variables in developing SCF processes for biocide treatment of wood and wood-based products.
M E Anderson, R J Leichti, J J Morrell

Semi-Solid State Bioremediation of CCA-Treated Wood Using Malted Barley as a Nutrient Source
2002 - IRG/WP 02-50184
Bioremediation processes for recovery and reuse of CCA-treated wood invariably increase the cost of any secondary products manufactured from the remediated fiber. Microbial remediation using either bacteria or fungi has been shown to remove heavy metals from CCA-treated southern yellow pine (SYP). In a two-step remediation process utilizing oxalic acid extraction and the metal-tolerant bacterium Bacillus licheniformis, 70-100% of the copper, chromium and arsenic can be removed from CCA-treated SYP, but the liquid culture medium used to support the bacterial growth renders this process costly. Processing costs could be partially offset if the culture medium were replaced with an industrial by-product. In this study, an abundant by-product of the brewing industry, malted barley, was evaluated as a replacement for commercial nutrient broth in the bioremediation process for CCA-treated SYP. Malted barley’s high moisture and nutrient content should support bacterial growth. When malted barley was substituted as a growth substrate for nutrient broth, it was discovered that either the culture inoculum or wood itself provided sufficient nutrients for the growth of B. licheniformis. Seventeen percent of the copper and 15% of the arsenic was removed from an aqueous slurry of CCA-treated SYP following bacterial remediation with B. licheniformis. When oxalic acid extraction preceded the aqueous bacterial culture of CCA-treated SYP, 21% Cu, 54% Cr and 63% As were removed. Incidentally, malted barley acted as a biosorbent, removing heavy metals from the liquid culture upon their release from CCA-treated SYP.
C A Clausen

Evaluation of teak sawdayst Tectona grandis L Fil as a potential source to obtain a natural wood preservative in Colombia
2004 - IRG/WP 04-30356
Plantation Teak (Tectona grandis L. Fil) has been tested as a possible source of natural wood preservatives due to the known excellent durability of old-growth teak wood. Field tests (ground proximity termite and above ground simulated decking exposures) were established in Colombia in April 2003 at two different test sites with different climates (Tropical Dry and Rain forest). Teak heartwood extracts were obtained using Soxhlet extraction with chloroform-methanol and methanol-ethanol as solvents, for two different mixtures at three different concentrations. Sapwood stakes of Patula pine (Pinus patula) and Globulos eucalyptus (Eucalyptus globulus) were vacuum pressure impregnated with these extracts, and control stakes were impregnated with CCA Type C and ACQ Type D at two nominal retentions (1 and 4kg/m3). The test sites have been found to be very active for both decay and termites. After only 9 months exposure termite attack has been observed from four species (Nasutitermes, Heterotermes, Triangularitermes, Velocitermes), and several basidiomycetes fungi have also been isolated from the test samples (Trametes, Schisophyllum, Poria). The results show that up to 100% of the samples have been subject to fungal attack, although in most samples only superficial trace attack has occurred in the exposure period. In contrast, termite attack has been rapid, primarily on the eucalyptus samples, which are suffering substantial degradation.
A Castillo, Y Cabrera, A F Preston, R Morris

Applicability of supercritical carbon dioxide to the preservative treatment of wood-based composites
2001 - IRG/WP 01-40199
Treatability of five structural-use wood-based composites (medium density fiberboard, hardwood plywood, softwood plywood, particleboard and oriented strand board) was evaluated when supercritical (SC) carbon dioxide (CO2) was used as a carrier solvent. Treatments were conducted at three temperature 32 levels (25, 35 and 45°C) and two pressure levels [80 kgf/cm2 (7,845 kPa) and 120 kgf/cm2 (11,768 kPa)]. Although small changes in weight and thickness of the wood-based composites were caused by treatments with SC-CO2, all treated materials did not sustain any physical damage. These results suggest that the treatment conditions provided the immediate penetration of SC-CO2 into the wood-based composites without any critical pressure gradient between outer and inner zones. Strength properties of the treated wood-based composites significantly improved after treatments in most cases. In contrast, a remarkable drop in strength properties occurred in oriented strand board specimens. Further studies are underway to determine the optimum treatment conditions using biocides incorporated into the mixing or treating vessel.
M Muin, A Adachi, K Tsunoda

Evaluation of tropical wood by-products as a potential source for termite control products
2001 - IRG/WP 01-10408
Termites damaging in houses represent an ever growing threat in Europe, where the phenomenon has accelerated during the last ten years, as well as in the tropics, where infestations are permanent. To fight against this plague, the current methods used, through injection of organochloric or organophosphorized products into the timber structures and walls, are belonging to the past due to the toxicity and harmful consequences of their use on the environment. New techniques were developed and research organisations are still working on minimizing the environmental impacts through the elaboration of new products. Some tropical wood species from French overseas territories (mainly French Guyana), like Ocotea rubra, Licaria canella and Aniba parviflora (Lauraceae), contain repellent, antifeeding or toxic substances which might be extracted to obtain molecules to be used for new wood preservatives. CNRS and CIRAD-Forêt are currently elaborating techniques that will allow to discriminate the possible effects of various molecules contained in sawdusts as regards to termites. Both termite species, Heterotermes indicola and Reticulitermes santonensis, have shown different behaviours depending on the wood species. These wood species were consequently classified according to their repulsive, antifeeding or toxic effects against both termite species studied. Considering the results obtained, it would then be worthwhile to use wood wastes from sawmills. Being so, the up-grading of by-products can be the basis for formulations of new wood preservatives with low environmental impacts and still providing durability against termites to wood species with a low natural durability.
A Zaremski, S Robert, J-L Clement, D Fouquet

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