Your search resulted in 574 documents. Displaying 25 entries per page.
Soft-rot control in hardwoods treated with chromated copper arsenate preservatives. Part 3: Influence of wood substrate and copper loadings
1977 - IRG/WP 2100
The hypothesis is proposed that hardwoods need more chromated copper arsenate (CCA) than softwoods to protect them from soft-rot attack mainly because hardwoods are more readily consumed by soft-rot fungi. Simple model systems, using copper-supplemented agar or groundwood pulp treated with CCA showed that fungi tolerated more toxicant (copper) as more available substrate (malt) was provided. Soft-rot tests with CCA-treated hardwood blocks provided typical dosage-response curves when results were expressed as a ratio of substrate to toxicant (wood to copper). Furthermore, hardwoods needed 10 to 20 times more copper as CCA than softwoods to prevent soft-rot attack. When CCA was substituted by ammoniacal copper arsenate in 5 hardwoods, similar threshold values for soft-rot attack were obtained in terms of a wood-to-copper ratio. Hence, CCA may be behaving poorly against soft-rot fungi in our hardwood specimens mainly because the substrate contained too little copper. The practical implications of these results are discussed.
M A Hulme, J A Butcher
Fungitoxic effect of the quaternary ammonium compounds preservatives against Basidiomycetes by using agar-plate and agar-block methods
1996 - IRG/WP 96-30118
Results of investigations on the fungitoxic value of three versions of wood preservatives based on the quaternary ammonium compounds (lauryldimethylbenzylammonium chloride, lauryldimethyl-benzylammonium bromide and alkylbenzyldimethylammonium chloride) and borates in relation to the wood destroying fungi have been presented. The agar-plate (screening) and agar-block method were applied. A wide range of the fungitoxic activity of all the three formulations and a very small leachability were proved.
J Wazny, P Rudniewski
Screening wood preservatives: Comparison of the soil block, agar block and agar plate tests
1993 - IRG/WP 93-20001
Several test procedures have been developed over the years to screen potential biocides for their value as wood preservatives. Each test has inherent advantages and disadvantages. In this paper the relative merits of the soil block, agar block and agar plate tests are compared. Eight commercially available biocides encompassing inorganic and organic systems were tested against four basidiomycete decay fungi. Each biocide was ranked according to its performance in the three tests. The results show that the relative efficacy of the different biocides is dependent on the screening test. Biocides can be separated on the basis of their chemistry. "Fixed" inorganic preservative systems perform better in tests which employ wood as a substrate material. Organic systems perform well in both the agar plate and wood-containing tests. Furthermore, the agar plate technique shows promise for detecting synergism between biocide components. It is concluded that all of these test methods should be considered to efficiently screen biocides for use as wood preservatives.
K J Archer, D D Nicholas, T Schultz
Activity of Two Strobilurin Fungicides Against Three Species of Decay Fungi in Agar Plate Tests
2017 - IRG/WP 17-30704
The objective of this study was to examine the toxicity of strobilurin fungicides against wood decay fungi in order to assess their potential to act as a co-biocide for copper-based wood protection. Two strobilurin fungicides, Heritage (50% azoxystrobin active ingredient) and Insignia (20% pyraclostrobin active ingredients), and copper sulfate pentahydrate were tested against one white rot fungus (Trametes versicolor) and two brown rot fungi (Gloeophyllum trabeum and Fibroporia radiculosa). SHAM (salicylhydroxamic acid) was also included in the study because it is a known potentiator of strobilurin activity. All treatments were incorporated in an agar-based media and evaluated for their effects on mycelial growth rate. Based on minimum inhibitory concentration values found for F. radiculosa (a copper-tolerant fungus), Insignia was 5.5x more toxic than Heritage. SHAM at 100 ppm, increased toxicity 9x for Heritage and 1.2x for Insignia. In a 20-day toxicity screening study, the four one-compound treatments tested were: copper sulfate (5000 ppm), Heritage (20 ppm), Insignia (20 ppm) and SHAM (100 ppm). The two two-compound treatments were: Heritage + SHAM and Insignia + SHAM. The two three-compound treatments were: copper sulfate + Heritage + SHAM and copper sulfate + Insignia + SHAM. For the two copper-susceptible fungi (T. versicolor and G. trabeum), the treatments that caused complete growth inhibition were copper sulfate alone and the two three-compound treatments (copper sulfate + Heritage + SHAM and copper sulfate + Insignia + SHAM). For F. radiculosa, the two- and three-compound treatments were the most toxic, with maximum daily average growth rates statistically similar to the copper sulfate treatment. A key result, however, was that only the three-compound treatment of copper sulfate + Insignia + SHAM completely inhibited growth of the copper-tolerant fungus. Thus, it appears that pyraclostrobin, which is the active ingredient in Insignia, has greater potential than azoxystrobin to act as a co-biocide for completely inhibiting growth of a copper-tolerant fungus.
J D Tang, T Ciaramitaro, M Tomaso-Peterson, S V Diehl
Essais mycologiques sur poteaux traités à la Wolmanit C B
1974 - IRG/WP 339
D Ollier, C Jacquiot
Contribution to the testing of wood based board material
1982 - IRG/WP 2176
R G Lea
Study of the natural durability and impregnability of a metropolitan species of tree
1986 - IRG/WP 2261
The current and predictable evolution of construction timber supply conditions is motivating research for a more efficient utilization of native woods. It is now important to determine statistically reliable impregnability values on a national scale, and to evaluate the natural durability of woods recently introduced in France, or economically important native woods.
M E Mathieu
Sub-group on Basidiomycete tests: Proposals for Sub-group programme of work
1979 - IRG/WP 2127
During the IRG 10 Meetings in Peebles, Scotland in September 1978, it was resolved to establish within Working Group II a sub-group on testing wood preservatives against basidiomycete fungi. The terms of reference and scope of the sub-group's activities were to be determined by consensus among members who registered an interest. Dr A F Bravery (PRL, UK) was asked to act as co-ordinator. During the course of the Peebles Meeting the following members registered their intention to participate: Dr D Aston (UK), Dr C Coggins (UK), Mr G Fahlstrom (USA), Professor D French (USA), Professor C Jacquiot (France), Mr B Jensen (Denmark), Dr A Ofusu-Asiedu (Ghana), Miss J Taylor (UK). Since there was insufficient time to convene an inaugural meeting in Peebles the present paper has been prepared as a basis for discussions and to facilitate initiation of active collaboration. It is hoped that members will offer individual comment in order to define the desirable scope of the sub-group's work and to refine ideas for collaborative or co-ordinated experimental work.
A F Bravery
A laboratory evaluation of the susceptibility to biological attack of glued laminated pine timber
1991 - IRG/WP 2387
In the scope of a research programme concerning the use of maritime pine (Pinus pinaster) to produce glued laminated timber structures in Portugal, the natural durability of this material was checked by using laboratory test methods. An European standard, EN 113, was used to test durability against basidiomycetes and a test method developed at LNEC for termites was adapted for this purpose. From the results obtained, it seems that the existence of glue layers does not influence the natural durability of the material under basidiomycetes attack. As for termites the method used indicates that they are unable to cross the glue layers though this effect would hardly be of importance for practical uses.
L Nunes, H Cruz
Determination of toxic limits of wood preservatives towards wood-destroying Basidiomycetes. Investigation on the effect of the use of two impregnated wood blocks and of one impregnated and an untreated block respectively in Kolle jars on the toxic limits of wood preservatives
1973 - IRG/WP 225
Some experiments with hexabutylditin against fungi
1977 - IRG/WP 388
The investigation was carried out in 1972 and 1973 to collect experimental data about the poisonousness of hexabutylditin (HBDT) against the woodrotting fungi Coniophora puteana (Coniophora cerebella), strain 15, and Chaetomium globosum, strain hexabutylditin was being manufactured by the Organisch Chemisch Instituut (O.C.I.) TNO, at Utrecht.
J W P T Van der Drift
The variability of preservative distribution in test blocks
1973 - IRG/WP 220
The techniques for the assessment of likely effectiveness of preservative systems have long been the subject of much discussion. The whole field has recently been reviewed by Hilditch and Hamblyn (1971) who described in detail many of the laboratory test procedures used, but who also indicated the deficiencies in many of these techniques. It has long been the view of many associated with the wood preservation industry that laboratory tests can only serve as a preliminary method of screening and that final approval by both the company marketing the development and independent authorities, on whom the burden of approval rests, can only be given after detailed testing in the field. The aim of the simple piece of work described in this paper, is to lok at the variability which one might expect in the distribution of preservative in test blocks destined for laboratory fungal evaluation.
F W Brooks, M R Gayles, R W Watson
Preliminary screening of diffusion formulations for the control of soft rot
1978 - IRG/WP 2104
We have an urgent need in Australia to develop in situ remedial treatments for the present population of in-service transmission poles. For various reasons we have opted for formulations which can be applied as bandage treatments and thus we are primarily concerned with assaying diffusable toxicants. Two basic approaches have been made: an assay of the formulation's toxicity; and a combination assay of the formulation's diffusibility and toxicity. Of the direct assay methods the filter-paper technique is the more rapid although with highly soluble formulations some leaching of toxicants will occur during the preparatory stages and probably during incubation also. Furthermore, filter papers are not strictly comparable to wood, and a modification we have considered is to use 'papers' prepared from mechanically beaten pulps rather than chemically degraded pulps. An additional modification would be to substitute veneers for filter papers, although this may give rise to surface concentration effects since the veneers could prove difficult to impregnate homogeneously. By far the most valuable technique for our own screening programme of potential toxicants to control soft rot in standing poles is the Petri dish/wood slab technique. While agar diffusion systems are rapid and provide valuable 'short list' data, the information obtained on diffusion rates cannot easily be applied to solid wood. Da Costa's slab technique is obviously advantageous in this respect. Furthermore, it can be so tailored that successive inocula can be sequentially assessed, thereby providing added information on component diffusion as well as total formulation movement. However, care must be taken in interpreting the data since it is not possible to distinguish directly which chemicals in a mult-component formulation have diffused first and hence which are the toxic ones. Similarly, it could be necessary to impose a time restriction on the test with certain types of formulations.
The use of plastic meshes in soft rot monoculture testing
1990 - IRG/WP 2353
Plastic meshes were introduced between the wood blocks and agar medium in a miniaturised soft rot monoculture test in order to minimise transfer of the preservative from the wood and mineral salts from the agar. Although several different sizes and types of mesh were used and the blocks were wetted up to an appropriate moisture content for soft rot attack the amount of decay was substantially reduced compared with the controls. Addition of mineral salts to the wood blocks in similar quantities to those in the agar aided decay but did not provide suitable conditions for maximum loss in weight.
S M Gray
Comparison between agar-block and soil-block methods for wood-destroying Basidiomycetes
1992 - IRG/WP 92-2401
The object of this work is to compare these methods in order to provide some information to help in the choice between them. The comparison was made by a statistical analysis (factorial completely randomized design) and by a discussion about other aspects of each method. An evaluation of some fungi on attacking wood and a comparison between Picnoporus sanguineus isolated from carpophore and decayed wood were made. The results indicated that the loss of mass was greater in soil-block. Besides, the activity of the fungi in this method was more homogeneous than in agar-block. However the soil-block method presents some difficulties not found in the agar-block method. As related to the performance of Picnoporus sanguineus strains, the greater loss of mass occured when it was isolated from carpophore, no matter what method was used. These results give important indications about the biological characteristics and the source of the strains.
M B B Monteiro, S Brazolin, G Catanozi
Assessment of the toxicity of some copper-, zinc- and boron-based wood preservatives to the cellar fungus Coniophora cerebella Schröet
1974 - IRG/WP 242
This article reports the use of a method based on the determination of the probability of the protection of timber against destruction by fungi. By converting the probability values to probit values and plotting them as a function of the amount of preservative retained in the timber, curves of the toxic effect are obtained, enabling any timber protection probability to be assessed.
V N Sozonova, D A Belenkov
Fungi used in standard tests on the toxicity value of wood preservatives in various European countries
1975 - IRG/WP 255
The aim of the present paper is to make the comparative analysis of test fungi used in various European countries in order to define the toxicity value of wood preservatives against fungi of the Basidiomycetes class. Only the methods with national standard rank, present on the currently binding standards list are taken for consideration. The analysis of similarities and differences in the choice of test fungi used in these methods should be a further step in the investigation on the unification of the test methods
Collaborative soft rot tests: Paper for discussion in Working Group II
1970 - IRG/WP II 5A
An account of the major part of the collaborative work on laboratory tests of toxicity of preservatives to soft rot fungi initiated by the European Homologation Committee at Delft in 1966 has been published in ‘Material und Organismen’ (1970) as a report of progress. The main objective of these collaborative tests, namely to establish a reliable and acceptable standard test method was not accomplished. The purpose of this paper is to comment upon the experience gained in order to facilitate discussions, at an IRG meeting, of any further proposals for achieving this objective.
J G Savory, A F Bravery
Preliminary results of the treatment of wood with chlorosilanes
1981 - IRG/WP 3172
It is clear from the initial data reported here that the treatment of pine sapwood with chlorosilanes under the reaction conditions employed did not significantly reduce the decay by both white rot and brown rot fungi. Only the dichlorosilane compounds showed to possess some protective action against fungal attack. Before drawing conclusions on the application of organosilicon compounds as potentially alternative wood preservatives much more work is needed. At present the anti-blue stain activity of the different types of chlorosilanes is being tested. Further investigation on the treatment is also required with respect to the effect of wood moisture content and the use of other types of acid acceptor on the silylation reaction. Current studies also deal with the effect of the treatment on physical and mechanical properties of wood. The initial physical tests on the sorptive and dimensional behaviour of treated wood revealed that the dichlorosilanes might give better results again.
Hygroscopicity of decayed wood - Implications for weight loss determinations
1996 - IRG/WP 96-20085
Hygroscopicity changes were observed in red maple blocks subjected to brown rot, white rot and soft rot. Brown rot reduced hygroscopicity, soft rot increased hygroscopicity, and white rot showed only a very slight increase in hygroscopicity. The effect of these changes on weight loss tests is a slight overestimation of weight loss for brown rot and a slight underestimation for soft rot and white rot. Hygroscopicity changes were similar prior to and after oven drying for white rot and soft rot, while for brown rot, the reduction in hygroscopicity was enhanced by oven-drying.
S E Anagnost, W B Smith
Protection of wood blocks treated with Trichoderma isolates selected on the basis of preliminary agar screening studies
1996 - IRG/WP 96-10154
Previously reported results of agar interaction screening studies for biocontrol agents of wood decay basidiomycetes showed two Trichoderma viride isolates, killed 16 of 19 target fungi (Tucker and Bruce, 1995). Testing of these isolates in wood was required to assess their performance at preventing decay of wood blocks. Standard testing of chemical wood preservatives is used to determine the toxic concentrations of preservative required to protect the wood against decay by basidiomycetes. As no ratified standards for testing biocontrol agents exist, two amended wood block testing standards were used to assess the two most effective Trichoderma isolates selected on the basis of preliminary agar screening studies. An agar based system similar to European Standard EN 113 (1980) and a soil block test based on the AWPA Standard 1413 (1977) were used with Scots pine and Sitka spruce pre treated with Trichoderma. Results indicated that wood blocks treated with Trichoderma isolates (T60) and (T110) were completely protected against decay by all the basidiomycetes tested irrespective of form of inoculum used (spores or mycelium) or timber species. Implications of the results for the use of agar plate interaction studies for screening biocontrol agents for subsequent use in wood block testing are discussed.
E J B Tucker, A Bruce, H J Staines
Resistance of various wood species against decay by Coniophora cerebella (Pers) Duby and Lenzites trabea (Pers) Bres
1976 - IRG/WP 142
Both fungi, Coniophora cerebella and Lenzites trabea, are important destroyers of timber. Coniophora often occurs inside buildings and Lenzites trabea has been observed on southern facades of buildings, on balconies and window frames. In most instances that we investigated coniferous timber had been decayed. But both species are known to attack also various hardwoods. For this reason tests similar to those carried out with Serpula lacrymans (see O. Wächli, Holz als Roh- und Werkstoff, 31, (1973) 96-102), have been made with both fungi on various home-grown and foreign wood species.
Evaluation of bacteria for biological control of wood decay
1990 - IRG/WP 1426
Laboratory soil-block and agar-block tests were carried out to evaluate the efficacy of bacteria as biological control agents against 5 brown-rot and 3 white-rot fungi. Pretreatment of Southern pine and sweetgum with a bacterial solution prevented decay in agar-block tests. However, the bacteria were generally ineffective in preventing decay in Southern pine, Douglas-fir, sweetgum and yellow poplar in soil-block tests. Wood blocks treated with an autoclaved bacterial solution were not decay resistant by either test method.
R Benko, T L Highley
On the laboratory use of X-rays in timber decay evaluations
1981 - IRG/WP 2144
The paper reports the results of laboratory experiments on the X-raying of some Pinus radiata sapwood blocks infected with Serpula lacrymans to determine the effect of density and moisture content on the absorption of X-rays by wood. It is concluded that with increasing moisture content there is a very marked increase in time required to pass a constant quantity of X-rays through a test block and the interpretation of X-ray data taken at unknown moisture contents may be questionable.
J D Thornton, J W Creffield, O Collett
Bestimmung der pilzwidrigen Wirksamkeit von Holzschutzmitteln gegen Moderfäule-Erreger
1977 - IRG/WP 2125
Ziel der vorliegenden Arbeit war der Vergleich der in verschiedenen Ländern zur Bestimmung der pilzwidrigen Wirksamkeit von Holzschutzmitteln gegen Moderfäule-Erreger angewandten Methoden. Als Vergleichsmaterial dienten drei normierte Methoden: die britische (42), skandinavische (45) und die in der DDR angewendete (47) sowie wichtige, von verschiedenen Fachleuten ausgeführte Arbeiten experimentellen Charakters. Die Analyse betraf vor allem folgende Probleme: Bereich der Anwendung der Methoden, Trägersubstanz, Testorganismen, Bewertungskriterien der Ergebnisse sowie andere Fragenkomplexe. Es wurden die aktuellen Untersuchungsmethoden zur Bestimmung der pilzwidrigen Wirksamkeit von Holzschutzmitteln gegen Moderfäule-Erreger, die in verschiedenen Forschungsarbeiten angewendet worden waren, durchgesehen. Festgestellt wurden sehr starke Unterschiede der methodischen Grundsätze, die sowohl zwischen den Methoden als auch im Rahmen der verschiedenen Typen von Methoden bestehen; diese Unterschiede betreffen vor allem die für die Pilzzucht angewandten Nährböden, die Ausmaße der Proben, die Auswahl der zu untersuchenden Organismen u. a. m. Von den drei Arten der Methoden: dem Agar-Klötzchen-, Erde-Klötzchen- und Vermiculit-Klötzchen-Verfahren scheint besonders das letzte hinsichtlich der Wiederholbarkeit als auch im Hinblick auf die Vergleichsmöglichkeiten der erhaltenen Ergebnisse geeignet zu sein.