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Effects of some essential oils on wood destroying organisms
1993 - IRG/WP 93-10047
Three wood destroying fungi: Botryodiplodia theobromae Pat. (stain), Gloeophyllum sepiarium (brown rot), and Pycnoporus sanguineus (white rot) were exposed to six plant essential oils: the peppermint, kaffir lime or leech lime, lavender, tarragon, holy basil, and the eucalyptus. The peppermint oil showed most effective to inhibit fungal growth, while eucalypus oil was the least effective. The other oils inhibition rate varied according to the species of fungi. In the experiment of the powder post beetles Heterobostrychus aequalis Waterh., the insects were killed within three days in the oil of tarragon, eucalyptus and holy basil, while in lavender oil they could live to ten days the same as controls. But on the contrary in the oil of peppermint and kaffir lime, some of them could even lived longer than the controls.
K Atisongkroh, C Anantachoke, P Lekuthai, S Pensook, T Kittirattrakarn

An evaluation of chemical pre-treatments for controlling kiln brown stain in radiata pine
1997 - IRG/WP 97-30124
Clear radiata pine (Pinus radiata D. Don) is widely used for fine millwork owing to its attractive light colour. However, kiln drying of radiata pine sapwood often results in the development of a brown stain causing substantial loss in revenues in New Zealand's high-value export markets. In this study chemical pre-treatments were evaluated for their ability to control the formation of kiln brown stain in the drying of radiata pine lumber. Of the eight chemical agents trialed, a reducing agent was identified to virtually eliminate kiln brown stain. Current research efforts are now concentrated on the development and application of a chemical pre-treatment process which could be used in industry, and will be discussed.
B Kreber, A McDonald

Bacterial brown stain on sawn timber cut from water-stored logs
1992 - IRG/WP 92-1532
Brown stains which appear on the surface of sawn radiata pine cut from water-stored logs were identified as tannin-like compounds. They are derived from bacterial breakdown of flavanoid-glucosides. When timber is sawn from infected logs, the free flavanoids migrate to the wood surface as the timber dries. There, they condense and oxidise to form permanent brown discolourations. Stains occurred on sawn timber between 4 and 8 weeks of storage under water sprinklers. Kiln-drying resulted in more intense staining than did air-drying. Stain intensity was less in winter-stored logs than in summer-stored logs. Sprinkling logs with fresh water or debarking logs before storage had little consistent effect on propensity to stain
M E Hedley, R Meder

Performance of Tuff Brite C™ and other formulations against blue-stain, mold and brown-stain in freshly-sawn rubberwood (Hevea brasiliensis) in the humid tropics of Peninsular Malaysia
1997 - IRG/WP 97-30163
The relative anti-sapstain and anti-mold efficacies, including brown-stain development in freshly-sawn rubberwood (Hevea brasiliensis) in the Malaysian tropics, between selected water-based product concentrations of formulations Tuff Brite CTM without/with added Borax (at 1.5/0, 1/1.5, 1.5/1.5 and 2%/1.5%), PQ8TM without/with added Borax (at 2.5/0, 1.5/1.5, 2/1.5 and 2.5%/1.5%) and NeXgenTM/NeX-BriteTM combination (at 1/0.25, 1.5/0.25 and 2%/0.25%) were assessed visually. Rubberwood boards, dipped in these concentrations for 1 min. were subjected to an 8 weeks sapstain trial in a FRIM sawmill shed. Sodium pentachlorophenate/Borax combination (at 2/1.5 and 2%/2%) was the reference anti-sapstain chemical. The rough-sawn boards were rated for blue-stain and mold weekly, while both the planed and the internal faces of the boards, sawn lengthwise into two-halves, were rated for blue-and brown-stain only after 8 weeks. Results for the rough-sawn boards, planed boards and the internal faces of the boards revealed a generally consistent excellent performance of Tuff Brite CTM without/with Borax against blue-stain and mold in rubberwood, protection being marginally better than that of NaPCP/Borax. Over a range of concentrations, performance by the remaining fomulations PQ8TM without/with Borax and NeXgenTM/NeX-BriteTM were variable: rated satisfactory (generally <10% surface infected) and/or poor (31-50% of surface infected) against sapstain and/or mold. Against brown-stain development (i.e. to conserve the natural cream/yellow hue in rubberwood), Tuff Brite CTM without/withBorax also appeared to be relatively better (generally yellow-to-light brown hue) than the other formulations, but perhaps only marginally so than NaPCP/Borax (light blue as well as yellow-to-light brown hue observed).
A H H Wong, T L Woods

Reduction of kiln brown stain in radiata pine lumber after log fumigation with methyl bromide
1997 - IRG/WP 97-30129
Methyl bromide fumigation of freshly felled radiata pine log sections effectively killed living cells in parenchyma to at least 75mm into sapwood. Lumber cut from logs (fumigated and control) stored 1 month outdoors (dry) showed slightly reduced brown stain when kiln dried at conventional temperatures. A more dramatic reduction and elimination of brown stain was noted in lumber cut from fumigated log sections stored for 6 months under water. Brown stain prevention was noted at conventional as well as high temperature kiln drying schedules (up to 120° C). Limited inspection of planed samples did not indicate control of "kiln burn" in the high temperature dried lumber. The mode of action of fumigation in control of brown stain remains to be documented.
E Schmidt, M E Hedley, D R Page, D Cross

Pretreatment decay in poles of Pinus sylvestris
1987 - IRG/WP 1329
Storage damage by blue stain and decay in poles before impregnation has been increasingly observed during recent years and there have been reports that salt-impregnated poles today are of lower quality because of incipient decay being increasingly common. The attacks may have started at the time of cutting and then continued during the period of seasoning at the plant, which could be as long as two years. Sub-standard impregnation has been mentioned as a reason for the decay. However, microscopic examination of samples from newly-impregnated poles has shown that attacks of blue stain as well as of brown and white rot have sometimes been of such an extent that damage by micro-organisms before impregnation was the probable reason. The aim of the present work was to illustrate the extent of blue stain and rot in poles before impregnation and to survey the methods of bark removal and storing poles during seasoning in Sweden. The production of treated poles of pine (Pinus sylvestris L.) in Sweden during 1985 was 74,300 m³ (51,200 m³ with creosote and 23,100 m³ with water-borne). The amount exported was 27,900 m³ (26,100 m³ with creosote and 1,800 m³ with waterborne CCA-type). At the time of the investigation there were nine major impregnation plants for poles in Sweden.
H Lundström, M-L Edlund

Impact of decay and blue stain causing fungi on the structural integrity of wood
2009 - IRG/WP 09-10699
The potential influence of diverse decay patterns caused by different brown rot provoking basidiomycetes on the structural integrity of wood was investigated. Additionally the potential impact of blue stain on the structural integrity was examined. Therefore decayed Norway spruce (Picea abies Karst.) specimens representing a wide range of mass loss, caused by four different brown-rot fungi and one white-rot fungus, were applied to a high-energy multiple impact (HEMI) -test series. The relationship between the resistance to impact milling (RIM) and the mass loss by fungal decay could be subdivided in three areas: 1. Prior to measurable mass loss a strength reduction was detectable due to the depolymerisation of wood cell wall components. 2. Between 0 and 25-30% mass loss RIM decreased with increasing mass loss. 3. Above 30% mass loss RIM increased again due to gluing effects of the fungal mycelium. The influence of the different brown rot fungi on the structural integrity of the wood differed slightly, but partly significantly. According to preliminary results blue stain caused by Aureobasidium pullulans and Sydowia polyspora was found to have no significant impact on RIM.
C Brischke, C Welzbacher, T Huckfeldt, F Schuh

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&apos;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

A comparison of soft rot, white rot and brown rot in CCA, CCP, CCF, CCB, TCMTB and benzalkonium chloride treated Pinus radiata IUFRO stakes, after 9-15 years exposure at five test sites in New Zealand
1991 - IRG/WP 1485
The aim of this study was to determine if decay type varies significantly between five field trial test sites of different soil type, aspect and climate in 9-15 year old, replicate CCA, CCF, CCP. CCB, TCMTB and AAC treated IUFRO stakes. A visual on-site assessment of decay type on every test stake was made and observations confirmed by microscopical examination. Regression analyses were used to determine significant differences of percentage frequency of occurrence of each rot type between sites and preservatives. Large differences in percentage frequency of occurrence of rot type were evident between sites. One site was dominated by brown rot (85%) and two were dominated by soft rot (99 and 91%). The fourth site had intermediate proportions of brown rot (40%) and soft rot (71%) but had the second highest occurrence of white rot (32%) (highest = 37%; lowest = 11%). The fifth site was distinct in that a large proportion of stakes (69%) had both well established brown rot and soft rot. Stakes at the other four sites tended to have only one rot type. Some highly significant preservative effects were also found. Possible causes of these differences are discussed in terms of inter-site soil type, climate and other differences.
R N Wakeling

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

Screening potential preservatives against stain and mould fungi on pine timber in Zimbabwe
1995 - IRG/WP 95-30063
The search for environmentally and toxicologically safer chemicals for use in the timber preservative industry against stain and mould fungi has been intensified during the past few years. Results of field tests with two chemicals previously evaluated in the laboratory are presented. The conventional sodium pentachlorophenate was the more efficacious chemical against stain and mould fungi, providing up 90% control at a concentration of 2.5%. A potential alternative, Stopstain a borate-based chemical, gave results only slightly better than the untreated control timber, at a concentration of 5%. Unless the environmental cost and toxicological hazards of traditional chemicals are highlighted the newer and safer chemicals will be reluctantly accepted by industry as they are regarded as being prohibitively expensive.
A J Masuka

Blue stain in service on wood surface coatings. Part 3: The nutritional capability of Aureobasidium pullulans compared to other fungi commonly isolated from wood surface coatings
1993 - IRG/WP 93-10035
The nutritional capability of Aureobasidium pullulans was previously examined, using agar plate tests, with regard to nutrient sources that are potentially available in fresh and weathered wood (Sharpe and Dickinson, 1992). This study compared these findings with the nutritional capability of four other fungi (Alternaria sp., Cladosporium cladosporoides, Stemphylium sp. and Trichoderma sp.) commonly isolated from wood surfaee coatings. The liquid culture techniques were used to assess the relative abilities of the fungi to utilise a range of simple sugars, wood sugar alcohols, hemicelluloses, cellulose and lignin degradation compounds. The observations were used to explain why Aureobasidium pullulans is able to occupy so successfully, often in monoculture, the wood-paint interface niche.
P R Sharpe, D J Dickinson

Report on the activities of the European Standardization Committee CEN/TC 38 'Methods of Testing wood preservatives'
1980 - IRG/WP 279 E
G Castan

Types of decay observed in CCA-treated pine posts in horticultural situations in New Zealand
1984 - IRG/WP 1226
The few reported failures of 11-12-year-old horticultural posts in New Zealand in 1982 were caused by brown-rot. A subsequent survey of CCA-treated posts in all the major horticultural areas has revealed decay of many posts. A microscopic examination of these posts has shown decay by brown-rot, white-rot, soft-rot and bacteria. Several types of bacterial decay have been observed.
J A Drysdale, M E Hedley

The dry rot fungus and other fungi in houses. Part 2
1993 - IRG/WP 93-10001
J Bech-Andersen

Low temperature drying conditions of Pinus radiata wood for avoiding internal stain
1989 - IRG/WP 3507
It has been observed that, if in little sawmills, timber is dried with a low temperature schedule, it arrives at destination with internal sapstain besides of superficial mould. In this study, the lowest drying temperature at which wood should be exposed for sterilization, which results to be 52°C, is searched. It is not possible to avoid entrainment of pentachlorophenol, even though a waiting period of 72 hours after dipping the wood in a pentachlorophenate/borax solution before drying is considered. The residual content of pentachlorophenol in wood should be at least 400 µg/cm² or the moisture content less than 23% for avoiding the development of mould.
M C Rose

Effects of acetylation on the dimensional stability and decay resistance of kenaf (Hibiscus cannabinus L.) fiberboard
1996 - IRG/WP 96-40059
The objective of this study was to investigate the influence of the acetylation treated kenaf fiber, Phenol formaldehyde resin content level, and three fungi species on the dimensional stability and decay resistance of high density non wood composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness, length changes, and decay resistance of the high density kenaf fiberboards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Rowell

Physical properties of ß-1,4-Xylanase produced by Postia (=Poria) placenta: Implications for the control of brown rot
1987 - IRG/WP 1318
The degradation of hemicelluloses is an early event in wood decay by brown-rot fungi. An understanding of the physical properties of hemicellulases may suggest target mechanisms for the development of new control agents. Endo-b-1,4-xylanase was partially purified by column chromatography from wood decayed by Postia (= Poria) placenta. The enzyme was extremely resistant to denaturing conditions; no loss of activity was detected after 2 h in 9 M urea or 6 M guanidine-HCl. Boiling the enzyme for 5 min in 2.5% SDS + 0.5% b-mercaptoethanol reduced its activity by 65%, as measured by the production of reducing sugars. The activity of a-D-galactosidase, another enzyme detected in large quantities in the decayed wood, was reduced by 98% under these conditions. Optimum pH and temperature ranges were pH 2-6 and 50-60°C, respectively. The enzyme appears to be a glycoprotein containing 50-60% carbohydrate (w/w); the carbohydrate moiety may protect the enzyme from adverse environmental conditions. The control of brown rot by in situ inactivation of xylanase may not be feasible because of the enzyme&apos;s extreme stability.
J A Micales, F Green III, C A Clausen, T L Highley

A new concept of oxalic acid biosynthesis in physiology of copper-tolerant brown-rot fungi
2001 - IRG/WP 01-10394
Recently, a wide variety of roles of oxalic acid (oxalate) in wood decay systems have been receiving much attention. Copper tolerance of wood-rotting basidiomycetes has been believed to be due to the detoxification of copper wood preservatives by oxalate produced by these fungi. However, biochemical mechanism of oxalate biosynthesis in relation to physiology of wood-rotting fungi has not been elucidated although two oxalate-forming enzymes, oxaloacetase and glyoxylate dehydrogenase, have been studied in our laboratory. Recently, a new role of glyoxylate cycle in oxalate biosynthesis in wood- rotting fungi has been presented, and the cycle commonly occurred to varying extents among the fungi although they were grown on glucose. Enzymatic analyses showed that isocitrate was cleaved by isocitrate lyase in the glyoxylate cycle rather than oxidized by isocitrate dehydrogenase in tricarboxylic acid (TCA) cycle, and the fungi were found to lack a normal TCA cycle due to the absence of - ketoglutarate dehydrogenase. It is noteworthy that glucose was efficiently converted to oxalate in a theoretical yield of about 80%, accumulating in the culture media of F. palustris. The results further indicate that acetyl-CoA derived from glucose was not completely oxidized to CO2 in TCA cycle but was mainly converted to oxalate with help of the other coupling metabolic cycles, including glyoxylate cycle. Formation of oxalate from several intermediary metabolites using cell-free extracts of F. palustris confirmed that oxalate is also the final product of the metabolic pathway in the in vitro system. Thus, it is proposed as a new concept that most of copper-tolerant brown-rot fungi may acquire the energy by oxidizing glucose to oxalate, i.e. oxalate fermentation expressed in the following equation; Glucose + 5O2 --> 2 Oxalate + 2CO2 + 4H2O.
E Munir, T Hattori, M Shimada

Mould resistance of lignocellulosic material treated with some protective chemicals
1984 - IRG/WP 3294
Effectiveness of preserving lignocellulosic material against moulding by treatement with water solutions of commercial wood preservatives and mixtures of various inorganic salts was investigated and compared with the effectivenes of sodium pentachlorophenoxide and boric acid.
K Lutomski

Field trials of anti-sapstain products. Part 1
1991 - IRG/WP 3675
The results obtained in two field tests of anti-sapatain products, carried out in four locations in Portugal, are presented. Boards from freshly cut logs were hand-dipped, close staked and left to dry for periods from four to six months. The results obtained seem to indicate that some of the products tested performed at least as well and sometimes better, than a 3% NaPCP solution which was used as control product.
L Nunes, F Peixoto, M M Pedroso, J A Santos

Durability of larch (Larix spp.) wood against brown-rot fungi
1997 - IRG/WP 97-10228
Durability of the heartwood of Larix decidua, L. sibirica, L. gmelinii, L. gmelinii var japonica, L. gmelinii var olgensis and L. sibirica x decidua against brown rot fungi Coniophora puteana, Poria placenta and Gloeophyllum trabeum was tested according to EN 113 test method. Parallel samples were used to study the amount and composition of wood extractives. The sample trees originated from the research forest of Punkaharju Research Station. The average age of the trees was 60 years. In addition, from L. sibirica also trees at 25 and 102 years were used. Results show that the durability of larch is depending on species, age of the tree, the wood part (inner or outer heartwood) and fungus. The average durability of larch heartwood was equal to class 3 or 4 (moderately or slightly durable, according to the standard EN350:2) and comparable with the durability of pine heartwood (Pinus sylvestris L). However, the durability of L. gmelinii var olgensis and L. sibirica (102 years old) was on the higher level than that of the other studied species but the durability varied even within the same board. Also the durability of wood from L. sibirica grown in the Russian side (Siberia) was studied. It was equal to that of the trees grown in Finland. The average amount of resin acids of larch heartwood was only about 0.1% (dry weight). In contrast, the heartwood of scots pine may contain up to 4.0% of resin acids. Resin acids are found to inhibit the linear growth of certain fungi. Interestingly, the largest amounts of resin acids (0.3%) were found in the heartwood of L. gmelinii which also showed high durability. The concentration of water soluble extracts (mainly arabinogalactan) of larch heartwood was quite large, varying between 3.2 - 20.5%. The concentration of water soluble extracts in the heartwood increased along the age of the trees. Lowest level of extractives were found in Larix decidua which was also the least decay resistant species. The durability of wood in different targets and the role of different chemical compounds of larch heartwood on decay resistance needs to be clarified.
H Viitanen, L Paajanen, P Saranpää, P Viitaniemi

Some characteristics of Pinus radiata wood from trees subjected to resin extraction
1987 - IRG/WP 3403
35 year old Pinus radiata trees growing in La Puntilla (lat. 37° south, long. 72,4° west), Chile, were subjected to resin extraction 5 years ago. After harvesting them simultaneously with control trees of the same place and age, probes were taken from the bottom of each pole, at 3.4 m, 7.8 m and 11.4 m height. Analysis of ethanol/benzene extract, CCA salt penetration tests and sapstain and brown-rot development rate were performed. The extract content differed in both groups. In the ascendent sense it decreases in unextracted trees and increases in extracted. CCA salt penetration was deeper in treated trees than in untreated. Wood subjectect to resin extraction was less susceptible to sapstain development. No significant difference was detected in both groups in relation to the development of brown-rot.
M C Rose, J Navarrete, G Sandoval, A Bedoya, L Ortega, R Zurita

Physical and biological properties of albizzia waferboards modified with cross-linking agents
1995 - IRG/WP 95-40043
Chemically-modified low-density waferboards with cross-linking agents were produced using a fast-growing species of hardwood albizzia (Paraserienthes falcata Becker) as a raw materials and isocyanate resin as a glue adhesive. For the chemical modification, the vapor-phase formalization of the boards and the pad-dry-cure treatment of wafers with cross-linking agents were employed. The vapor-phase formalization was conducted for 5, 10 and 24 hours using tetraoxane as a source of formaldehyde, and the pad-dry-cure treatments with glutaraldehyde and ethyleneurea compound (DMDHEU) were made after impregnation of their 5 and 10% aqueous solutions of each chemical. Sulfur dioxide was used as a catalyst in both treatments. About 70% of antiswelling efficiency (ASE) was gained in all treated boards irrespective of reaction time or solution concentration. All treated boards were very stable to water soaking even in the 2-hour boiling on thickness swelling as well as linear expansion. Laboratory tests with brown-rot and white-rot fungi revealed that decay was completely suppressed in formaldehyde-treated boards, and small losses in weight were counted in other treated boards. All treated boards were also effective in resisting to the attack by the destructive termite Coptotermes formosanus.
S Yusuf, Y Imamura, M Takahashi, K Minato

Evaluation of the effectiveness of three microbiocides in the control of sapstains
1982 - IRG/WP 3212
Results of field test on the effectiveness of BUSAN 30, CAPTAN, FOLPET against mould and sapstain in Pinus elliottii are presented. The viability of use of FOLPET in Brazil as an alternative to sodium pentachlorophenate is also discussed.
S Milano, J A A Vianna Neto

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