Your search resulted in 94 documents. Displaying 25 entries per page.
Bacterial staining of samba (Triplochiton scleroxylon)
1988 - IRG/WP 1362
Red- and green-stained areas on Samba wood have been tested by IR, X-ray and Neutron Activation Multielement Analysis. No difference could be seen between stained and unstained areas. The red- and green-staining seem to be related to the bacteria Pseudomonas aeruginosa which were isolated from both red- and green-stained areas on the wood surfaces.
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
Microbiological degradation of wooden piles in building foundations
1988 - IRG/WP 1370
White rot, soft rot and bacterial attack have been detected in softwood piles under buildings. In some cases bacteria were found to be the main degradation organisms in the studied piles. The water content of degraded piles was very high. The compression strength was quite low also in the piles deteriorated by bacteria. The density of wood was very variable, and the degree of degradation could not be evaluated according to density analyses.
L Paajanen, H Viitanen
Fungal and bacterial attack of CCA-treated Pinus radiata timbers from a water-cooling tower
1991 - IRG/WP 1488
Transmission electron microscopy of decaying CCA-treated Pinus radiata timbers from an industrial water cooling tower showed presence of a thick biofilm covering some areas of the wood. The biofilm contained various morphologically distinct forms of microorganisms embedded in a slime. The study provided evidence of the activity of soft rot fungi and tunnelling and erosion bacteria in wood cells. The extent of damage to wood cells due to microbial activity varied, combined fungal and bacterial attack having the most damaging impact.
A P Singh, M E Hedley, D R Page, C S Han, K Atisongkroh
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
A laboratory method for assessing the effectiveness of fungicides in preventing the spread of decay fungi within packages of unseasoned lumber
1983 - IRG/WP 2202
To study the deterioration caused by decay fungi in the laboratory, a method for testing fungicides for their effectiveness in preventing spread of decay was devised. Some experiments using this method are reported here.
A J Cserjesi, E L Johnson, A Byrne
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.
Ultrastructure of the attack of a naturally durable timber by tunnelling bacteria
1990 - IRG/WP 1462
The attack of the wood of Eusideroxylon zwageri, a naturally durable species, by tunnelling bacteria (TB) was examined by light microscopy and transmission electron microscopy. Observations were made primarily on fibres. Parenchyma were included in some cases. Both fibres and parenchyma are rich in extractives. In fibres, extractives are primarily present in the lumen. The amber colouration of fibre walls under the light microscope suggests that extractives may also permeate fibre walls. In parenchyma, extractives are present in large amounts in the lumen. Inner areas of parenchyma walls are also heavily permeated. The degradation of Eusideroxylon zwageri wood is markedly slower than any wood species we have examined before. However, in advanced stages of TB attack all areas of the fibre, except corner middle lamellae and extractive filled lumen, are heavily degraded. The degradation of Eusideroxylon zwageri wood involves other differences. The TB attack of the fibre wall starts from the S1 layer moving inwards and the tunnels formed vary greatly in their form, ranging from long and relatively straight to "S","V", hook, folded and convoluted forms. These variations from previously observed appearances most likely reflect differences in the thickness and chemical composition of the fibre wall of Eusideroxylon zwageri wood from the woods examined previously.
A P Singh, T Nilsson, G F Daniel
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
Blue stain in timber in service. Results of co-operative tests to compare different artificial weathering systems 1981-82
1983 - IRG/WP 2193
The paper describes results of the third phase of co-operative laboratory experiments comparing the effects of different artificial weathering systems on chemicals to control blue-stain in service. Atlas, Xenotest and Marr equipments are shown to give essentially the same results for 5 of the 6 chemicals tested.
A F Bravery, D J Dickinson
Tentative method of testing wood preservatives against blue staining
1977 - IRG/WP 259
The blue stain of sawn wood is still a real problem in Poland. Although a preservative based on sodium orthophenylphenoxide has been introduced into sawmill practice, and the technology of wood protection developed with it, new information has been obtained concerning blue stain in wood material destined for export. In order to select new chemicals or to improve the effectiveness of the ones in current use it is necessary initially to carry out laboratory tests of the prepared chemicals to determine their efficiency.
E Tarocinski, O Lewandowski, M H Zielinski
Effects of timber surface properties and dipping conditions on uptake of antisapstain actives from two aqueous suspensions, and ultimate effects on efficacy against mould and staining organisms
1995 - IRG/WP 95-30073
Green-off-saw rough sawn Pinus elliottii (slash pine) boards were dipped in aqueous suspensions of two antisapstain formulations, and the resultant surface retentions of active ingredients MTC (methylene bisthiocyanate), CTL (chlorothalonil) or TCMTB (2(thiocyanomethylthio)benzothiazole) were monitored by chemical analysis. Surface retentions increased with suspension concentration and surface roughness, and decreased with initial timber moisture content. Dipping time beyond 20 seconds, timber basic density and earlywood content had little effect. Relatively low surface retentions, produced by dipping smoother boards with higher initial moisture contents, provided lower protection against mould and stain during seasoning than higher retentions. Equations describing the effect of surface retention on efficacy were developed for both formulations, and retentions providing complete protection under the conditions of the test were determined.
M J Kennedy, T L Woods
Molecular studies on isolates of Serpula lacrymans
1989 - IRG/WP 1421
The major protein species present in detergent extracts of 14 different Serpula lacrymans isolates have been compared, by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), with a standard strain, viz. Serpula lacrymans FPRL 12C. Following silver staining of SDS gels the major protein species identified in 12 isolates were similar to those found in the standard strain. However differences were found when the final two isolates were compared with FPRL 12C, both isolates had extra molecular species not present in 12C and both were lacking some present in the standard strain. Comparison of the protein species identified in Serpula lacrymans isolates with those identified in extracts of other fungal organisms, viz. brown and white rot causing basidiomycetes and non-basidiomycetes indicated that the Serpula isolates were more similar to each other than to other organisms. Some molecular differences could be identified when individual isolates were cultured on different media, i.e. liquid culture or agar, only minor differences were seen when individual isolates were subcultured. These results indicate that whilst care must be taken to ensure as near identical conditions as possible for culture of organisms if their molecular species are to be compared by SDS-PAGE and silver staining, consistent results can be obtained using this technique. The technique may therefore offer a method of distinguishing between isolates, strains and species of wood decay basidiomycetes, and identifying new isolates.
A Vigrow, D Button, J W Palfreyman, B King, B M Hegarty
Soft rot and bacterial decay in preservative treated eucalypt power transmission poles
1982 - IRG/WP 1155
Bacterial type decay was observed in CCA and PCP treated eucalypt power transmission poles. Detailed observations made with the SEM revealed bacterial colonisation and decay, especially in fibres. Plug samples taken from poles throughout Queensland were examined for preservative retention and presence of soft-rot decay. The severity of decay was different according to location, retention and species.
L E Leightley
Observations on the penetration of preservatives into green timber
1985 - IRG/WP 3335
Differences in the rate and extent of diffusion of MBT and NaPCP-based preservatives following a short dip treatment were observed. The importance of preservative distribution as well as toxicity to the target organisms in governing the ultimate performance of any anti-sapstain compound is discussed.
G R Williams, R A Eaton, D A Lewis
Bacterial wood degradation by a pure culture
1995 - IRG/WP 95-10093
A single-celled bacterium isolated from lake water yielded cell wall degradation in Scots pine sapwood samples. The bacterium attacked all cell wall layers in one month of laboratory culture. It was identified as Aureobacterium luteolum.
Biological control of blue stain on wood with Pseudomonas cepacia 6253. Laboratory and field test
1989 - IRG/WP 1380
Pseudomonas cepacia strain 6253 was tested as a biological control agent on wood samples under laboratory conditions, as well as in the field. In the laboratory this bacterium controlled blue stain on Pinus radiata, but field test were not totally satisfactory. However, after 2 months of field test, the test samples were 1/3 to 1/2 less stained then the control samples.
Some tests on ES - AS 11, a novel anti-sapstain formulation, and its properties
1987 - IRG/WP 3399
The results of some tests with the formulation ES - AS 11 are given. The formulation is an attempt to improve the performance of an anti-sapstain chemical by: 1) increasing its penetrability 2) uniquely combining its active ingredients. Very short times of treatment (dipping not longer than 5 seconds), low concentrations of active ingredients, and lower toxicological and environmental risks may be a promising result.
IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water: Final report
1987 - IRG/WP 4133
Three timbers chosen as reference species were treated with 3, 6 and 10% solutions of CCA and CCB preservatives and exposed for up to 93 months at 8 tropical and temperate marine sites. Eleven local species treated in the same way were exposed at 4 of the 8 sites. There was no apparent difference in performance between CCA and CCB treated specimens. The severest test site was Panama Canal but marine borer damage of specimens was recorded at all the test sites. Treated specimens of the reference species Alstonia scholaris and Pinus sylvestris were markedly superior in performance at all sites and Homalium foetidum was considered the best local species. Along with the reference species Fagus sylvatica, treated specimens of the remaining local species performed relatively poorly. All treated species were attacked by soft rot fungi, except treated Alstonia scholaris and Homalium foetidum which were superficially decayed by bacteria. The relative success of treated Alstonia scholaris in this trial is attributed to its permeability characteristics and acceptance of high preservative loadings, even preservative distribution and its high lignin content.
R A Eaton
The Role of Coformulants in Preventing Bacterial Biotransformation of IPBC
2002 - IRG/WP 02-10436
The inhibitory effects of disodium tetraborate decahydrate and benzalkonium chloride (BAC), two common coformulants of IPBC in antisapstain treatments, on an IPBC-transforming enterobacterial isolate ‘W1’ were determined by their effect on the specific growth rate constant in vitro. The IC50s of IPBC, BAC and borate were found to be 0.46, 0.026 and 5.7 mM respectively. The IC50 of the Arch antistain product AntibluTM Select was 0.024 mM, based on its BAC content. Although their IC50’s were significantly different, it was clear that the vast majority of the bacterial toxicity of the AntibluTM Select was due to its BAC content. The degradation of 0.4 mM IPBC by the bacterium W1, as measured by the accumulation of its degradation product, iodide, in liquid culture, was completely inhibited by BAC concentrations greater than 18 μM, and the toxicity of the spent culture medium to Aspergillus niger, as measured by an antibiotic assay disc assay, was not ameliorated above this concentration. Below 18 μM, the toxicity of the spent broth was significantly reduced, and the accumulation of iodide occurred rapidly. Demonstrating the toxicity of BAC to bacteria, and its consequent inhibition of IPBC degradation in vitro, are indicative of the importance of coformulation in controlling bacteria that might otherwise cause preservative loss, and of their significance in determining the ultimate environmental fate of cobiocides.
S R Cook, D J Dickinson
In vitro studies on the effect of chitosan on mycelial growth and spore germination of decay fungi, moulds and staining fungi
2004 - IRG/WP 04-10507
The effect of solubilised, low molecular weight chitosan on established mycelial growth of a range of decay fungi, moulds and staining fungi was investigated using nutrient medium amended with different concentrations of chitosan that ranged from 0.1 to 0.4% weight per volume (%w/v). Also, spore germination of Trichoderma harzianum and Leptographium procerum was examined on chitosan amended nutrient medium using visual and microscopic assessment. The results showed that chitosan affected mycelial growth of a wide range of test fungi which generally showed lower growth rates as the chitosan concentration increased. However, the degree of inhibition exhibited by chitosan varied with fungal species. Under the present test conditions, chitosan was fungistatic, but not fungitoxic, against established mycelium of the staining fungi tested and also two moulds, Botrytis cinera and Cladosporium herbarum, but not against any of the decay fungi tested. Spores of T. harzianum germinated on chitosan amended nutrient medium at all chitosan concentrations tested, except for the highest level (0.2%w/v) used, while L. procerum failed to germinate on 0.15 and 0.2%. Also, T. harzianum and L. procerum spores incubated on 0.15% and 0.2% chitosan failed to germinate when placed onto fresh malt extract agar suggesting fungitoxic activity of chitosan at these higher concentration levels.
C Chittenden, B Kreber, N McDowell, T Singh
Copper based water-borne preservatives: The use of a thin section technique to compare the protection of wood by copper based preservatives against soft-rot and bacterial decay
1987 - IRG/WP 2286
This paper describes the techniques developed and gives examples of results obtained for the performance of copper based wood preservatives against both the bacterial and fungal hazards.
A M Wyles, D J Dickinson
Preliminary note on the fungal problem of rubber wood
1983 - IRG/WP 3246
Susceptibility of rubber wood to fungal attack limits its wider utilisation. Fungal problems encountered in treating rubber wood with boron compounds by diffusion process have been discussed. Sodium pentachlorophenoxide and 2-thiocyanomethylthio benzothioazole (TCMTB) were investigated for possible control of fungal growth during diffusion storage and their performance has been reported.
Field and laboratory studies on anti-sapstain preservatives
1982 - IRG/WP 3205
The field tests included 11 different anti-sapstain preservatives and were carried out at different sawmills in southern Sweden. Drying conditions, climate and the local fungus flora were not identical for the different preservatives and comparisons between the preservatives should therefore be made with caution. Results obtained in the field tests are, however, in relatively good agreement with those found in the laboratory tests carried out with the pure preservatives. Especially Cuzol, a methylen-bis-thiocyanate/boric acid-product, showed a good effect against sapstain both in field and laboratory tests. However, Mykocid BS and Improsol 1 (two bifluoride products) as well as Mitrol 48 (benzalkonium chloride/guazatine) were also effective against sapstain. Hager Blue (boric acid/caprylic acid) was also fairly effective even if the untreated control material in this test was only moderately stained. Acceptable protection was obtained with the two Benomyl-containing preservatives and Thiobor (dimethyldithiocarbamate + borax). Mixtures of the various preservatives were tested in the laboratory as regards protective effect against sapstain, mould, thermotolerant mould and decay as well as chemical reactions that could be observed visually (precipitation, change in colour etc.). There was no absolute correlation between observed chemical reactions and changes in the biological effect. Mixtures resulting in reduced biological activity and which should be regarded less suitable are; Mykocid BS/ DuPont Benomyl, Cuzol/Thiobor, DuPont Benomyl/ Thiobor, Fennotox/Mitrol 48, Fennotox/Thiobor, Hager Blue/Sadolin Woodgard, Improsol 1/Mertect, Mitrol 48/Thiobor, Mitrol 48/Sadolin Woodgard and Mykocid BS/Thiobor. When mixing Hager Blue/Mykocid BS, Mitrol 48/Mykocid BS, Improsol 1/Cuzol and Mykocid BS/Cuzol precipitations occurred, which is a factor to be considered in practice since stirring may be necessary in the dipping tank. The preservatives based on bifluorides, Improsol 1 and Mykocid BS, penetrated about 1 cm into the wood after dipping and seasoning. A certain yellowish chemical staining was observed. Bifluorides are corrosive and attack steel and to a certain extent also concrete. Products containing boric acid and borates (Hager Blue, Thiobor, Benomyl + boric acid) also penetrated the timber to a certain extent. Thiobor reacted with certain parts of the heartwood which became slightly stained a reddish tone. The diffusion from the surface of the timber and inwards, which takes place when preservatives containing bifluorides, boric acid or borates are used, results in decreasing concentration of active components near the surface of the timber. This has to be considered when choosing the concentration of the treatment solution. Four of the preservatives included in the tests required stirring in the dipping tank. These are DuPont Benomyl 50, Sadolin Woodgard, Fennotox S2 and Mertect.
M-L Edlund, B Henningsson
Antifungal properties of new quaternary ammonium and imidazolium salts against wood decay, staining and mould fungi
2004 - IRG/WP 04-30347
The biological activity of twenty-four potential wood preservatives – imidazolium and quaternary ammonium salts with a modified anion structure was determined employing screening agar-plate and agar-block methods. Experiments were carried out on Scots pine (Pinus sylvestris L.) wood. The aim of the performed studies was to investigate the effect of structure modification of IC and QAC with organic anions or copper (ll) and zinc complexes on their biological activity against wood decay, staining and mould fungi. The fungicidal value of new compounds for Coniophora puteana ranged from 0.64 kg/m3 to 2.2 kg/m3. Aspergillus niger turned out to be the most resistant fungus to the action of modified IC and QACs, whereas Sclerophoma pityophila was effectively inhibited by the examined salts. The performed soil-block tests showed that the IC and QAC were leached from the experimental wood in conditions of contact with moist soil and revealed their fungal detoxification by mould fungi, especially by Gliocladium roseum. Observations made using the scanning electron microscope of the colonization and decay of treated wood by mould fungi confirmed tolerance of mould fungi to QACs.
J Zabielska-Matejuk, W Wieczorek