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Rapid Screening test of potential antimicrobial agents for wood coatings
2018 - RG/WP 18-20644
A two-part screening test has been developed to evaluate additives for wood coatings. First, an additive is tested in the microbial laboratory and evaluated based on its inhibitory properties against selected test organisms, directly on agar plates. A microbial growth analysis is prepared and evaluated. If the additive is considered effective, it will be tested in a standard top coating (acrylic or alkyd) and applied onto wooden panels for exposure in a growth chamber developed for this exact purpose. In the growth chamber there is a “24-7-365 constant” humidity and temperature as well as a constant spore pressure throughout the chamber. All test panels are evaluated every week for a total of 6-10 weeks. Every panel gets two evaluations. Respectively, based on the amount of mould attack and based on a qualitative overall visual appearance. It is possible to age the panels and coatings before the exposure in the mold chamber, either by QUV or in a state-of-the-art Weathering Machine, which also includes frost periods in between the UV and the rain, which is important for evaluation of coatings used in geographical areas with cold winters. With this two-part test, an additive can be screened within few weeks (plus any aging process) for its properties as antimicrobial additive in a wood coating.
J Stenbæk, E Morsing, T Østergaard Jensen

Biological screening assays of wood samples treated with creosote plus chemical additives exposed to Limnoria tripunctata
1980 - IRG/WP 408
Laboratory methods for exposure of treated wood coupons to Limnoria tripunctata are described. Chemical additions to creosote were screened using this method. Three pesticides, Endrin, Kepone, and Malathion proved particularly effective. The addition of varying percentages of naphthalene to creosote using several treatment methods are currently being assayed. Results to date show that the coupons treated by the empty cell method have better performance than those prepared by the toluene dilution method. The naphthalene coupons treated by the full cell method show no attack after six months' exposure.
B R Richards, D A Webb

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

Fungicidal activity of some organic solvents, copper carboxylates and their complexes with 2-aminoethanol
1997 - IRG/WP 97-30136
We evaluated the activity of eight organic solvents against wood - rotting fungus Trametes versicolor in order to choose the most appropriate one for rapid screening tests of some copper(II) carboxylates and their adducts with 2-aminoethanol. Their activity against the selected fungus was classified in the following order: chloroform > N,N-dimethylformamide > acetonitrile > methanol > dimethyl sulfoxide > ethanol > acetone. The non-polar white spirit did not dissolve in the growth medium and the results could not be directly compared with the results for other solvents. As an appropriate solvent for screening of the tested copper(II) carboxylates, dimethyl sulfoxide (DMSO) was chosen. Minimal inhibitory concentration against Trametes versicolor of the screened carboxylates was in the concentration range of 1x10-4 to 1x10-3 mol/l. Coordinated amine ligands slightly, and not significantly, decreased fungicidal properties of the tested carboxylates.
M Petric, F Pohleven

Current techniques for screening initial formulations against Basidiomycetes and soft rot
1978 - IRG/WP 2103
J D Thornton, H Greaves

Screening-method for the examination of the resistance against contact-insecticides of Lyctus brunneus Steph. beetles
1981 - IRG/WP 2148
A serie of filter-paper rondelles is treated with different concentrations of an organic insecticide dissolved in aceton. Beetles of Lyctus brunneus are put onto the dry surfaces. During the impact of the poison the knock-down is observed and after a following poisonfree holding, the knock-down and mortality are registred.
E Graf, B Lanz

A method for screening termite baits using Coptotermes lacteus mounds
1984 - IRG/WP 1237
A method with several variations designed to rapidly screen potential bait substrates using Coptotermes lacteus mounds is described. The equipment used in this method is relatively inexpensive, readily prepared in the laboratory, and easily installed into active mounds in the field. Bait substrates are in continuous contact with a 'high termite hazard', and may be monitored with minimum interference to the termites.
J R J French, P J Robinson

Laboratory evaluation of chemicals as termiticides
1986 - IRG/WP 1293
Laboratory procedures are described for screening chemicals against subterranean termites. Fast-acting compounds with persistent termiticidal activity are identified in tests using a soil substrate, and slower-acting bait toxicants are evaluated in a series of tests using cellulose substrates.
S C Jones

Preliminary results of investigations on screening test of chemical compounds suitable for the preservation of lignocellulosic materials against biodeterioration
1976 - IRG/WP 262
This paper investigates the possibilities of reducing the time needed for the determination of the effectiveness of chemical compounds from the point of view of their eventual application to lignocellulosic materials for preservation against decay and soft-rot.
K Lutomski, S S Neyman

Screening potential termiticides: Some thoughts and suggestions on methodology
1988 - IRG/WP 1363
While laboratory bioassays on the efficacy of potential termiticides against subterranean termites continues both to dominate and influence research efforts, suggestions are presented for the need to develop laboratory bioassays that more closely simulate "natural conditions". Not only is this considered desirable, but it will offer more confidence in laboratory and field evaluations and their analyses.
J R J French

Changes in the degree of decay of lignocellulosic substrate used in a screening test of fungicidal wood preservatives
1977 - IRG/WP 287
This report contains results of investigations aimed at: a) determination of the effect of the kind of substrate and species of test fungus on quantitative changes in used samples prepared from spruce cardboard, and b) comparison of the threshold fungicidal values of come fungicides determined with accelerated method, with values obtained by block method. During performed investigations, the method described in Document No.: IRG/WP/262 was used. Assesment of decomposition degree was based on the loss of weight and amount of NaOH consumption by the substrate.
K Lutomski

Development of novel techniques for evaluating the feeding rate of Limnoria lignorum with specific reference to temperature influences
1999 - IRG/WP 99-10325
The faecal pellet production of Limnoria lignorum placed into repli-dish chambers containing seawater and a small chip of untreated Corsican pine (Pinus nigra) was observed. The repli-dishes were kept at a range of constant temperatures between 10 and 25°C and the number of faecal pellets produced by each of the animals was monitored. It was found that faecal pellet length generally increased with gut length and that temperature had no effect on the faecal pellet length. There was considerable variation in faecal pellet production rates, both from day to day for any particular animal and from animal to animal. Faecal pellet production rate was generally highest between 15 and 21°C and decreased above 22°C. The production of faecal pellets tended to decrease during moulting. Gut passages per day increased from 1.1 at 13°C to 3.4 at 21°C followed by a decrease to 1.6 at 25°C.
A Praël, S M Cragg, R A Eaton

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

Evaluating the natural durability of a number of lesser known species of Ghanaian hardwoods using a short term laboratory assay
2004 - IRG/WP 04-10540
Resistance of a number of Ghanaian hardwoods to attack by the crustacean Limnoria quadripunctata was assessed by measuring the production of faecal pellets under forced feeding conditions over a two week period. Small sticks of commercially available, lesser known timber species, were leached in seawater for one week then placed in a cell culture chamber with one animal and 4 ml of seawater. At intervals, the number of faecal pellets per chamber was counted. The number of pellets produced by animals feeding on Scots pine sapwood, which is non-durable, and on greeheart or ekki, timbers with a reputation for resistance to marine borer attack, were used as a basis for comparison. Mortality rates were also compared. Lower pellet production rates and higher mortality rates were taken as measures of natural durability. Feeding on ekki (Lophira alata), kusia (Nauclea trillesii) and ananta (Cynometra ananta) was about one tenth of that on Scots pine. Mortality of animals with wonton (Morus mesozygia) was 90%, but high mortality did not occur with any of the other species.
J R Williams, S M Cragg, L M S Borges, B Shayler

The development of a screening method for the activity of pyrethroids against wood boring marine crustaceans, Limnoria spp
1978 - IRG/WP 443
The present work is concerned with the develepment of a suitable bio-assay technique to determine the biological activity (contact action) of pyrethroids against Limnoria spp. Estimates of the toxicity of three pyrethroids, permethrin, cypermethrin and decamethrin (the structures of which are shown in Fig. 1.) to the marine borer have been obtained.
D Rutherford, R C Reay, M G Ford

Agenda Special Seminar: Screening techniques for potential wood preservative chemicals
1978 - IRG/WP 2115
IRG Secretariat

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.
H Greaves

Evaluating the potential of modified wood for use in marine environments using a short-term laboratory bioassay
2004 - IRG/WP 04-10525
Chemically modified wood may be an alternative to preservative treated timber for marine structures. In this study a screening laboratory test using the wood-boring isopod crustacean Limnoria quadripunctata was used to assess the durability of chemically modified Pinus sylvestris, Pinus radiata and Picea sp. Most of the treatments used a combination of one of two of types of the resin dimethyloldihydroxyethyleneurea (DMDHEU) and phosphobutane tricarboxylic acid (PBTC). Untreated Pinus sylvestris sapwood was used as a non-durable comparison. Small test sticks from different types of modified wood were prepared and leached in seawater for 8 days prior to the experiment. A wood stick with a Limnoria and 4 ml of seawater was placed in each 12mm diameter well of a cell culture chamber. The number of faecal pellets produced by the animals was measured under these forced feeding conditions, and activity and mortality was recorded. With some treatments, no faecal pellets were produced, with others more faecal pellets were produced than with untreated Pinus sylvestris. Non-production of faecal pellets was sometimes due to mortality, but in some treatments there were also evidence of antifeedant effects as there was no evidence of acute toxicity Limnoria. However, some moribund animals were observed in these treatments and there was significant reduction in the number of pellets produced, so chronic toxicity may be suspected. The Arkofix type of DMDHEU gave significantly higher protection against borers than DMDHEU NG. A dose-dependent suppression of pellet production by PBTC was also detected.
L M S Borges, S M Cragg, M van der Zee

Screening of lignin peroxidase from white-rot fungi
1998 - IRG/WP 98-10274
Since lignin peroxidase was first found in the ligninolytic culture of Phanerochaete chrysosporium, it has been regarded as an enzyme responsible for the lignin biodegradation and studied comprehensively. As the results of these studies its unique characteristics have been revealed. On the other hand, the features of lignin peroxidase produced by other white-rot fungi have not been studied so much. In this study, over 80 white-rot fungi were examined for their ability to produce lignin peroxidase. Five fungi produced lignin peroxidase, and they were subjected to further investigations. These lignin peroxidases showed higher activity at pH 3.5 than pH 4.5 in the oxidation of veratryl alcohol. It could oxidize guaiacol slowly. These features are similar to those from P. chrysosporium. Newly isolated lignin peroxidase were inactivated by the reaction with hydrogen peroxide. There was a difference in the rates of the inactivation by the hydrogen peroxide treatment. The rate observed in the inactvation of lignin peroxidase from P. chrysosporium was moderate.
I Momohara

Practicability of bioassays in the evaluation of environmental risks in wood protection
1996 - IRG/WP 96-50071
As an example for the proofing of the practicability of bioassays in the evaluation of environmental risks in wood protection the ecotoxicological behaviour of CCF-impregnated timber was examined. After vacuum pressure impregnation specimen from shaped pine poles were tested on ecotoxicological effects of leachable compounds using sensitive aquatic organisms like fish, Daphnia and algae as bioindicators. According to proper impregnation the influence of leachable compounds from treated timber was significantly lower when compared with the acute aquatic toxicity of the preservative and its ingredients. This indicates the existance of safety factors and allows a differentiated estimation of environmental risks for impregnated wood. A general proposal for an ecotoxicological screening procedure in wood protection is presented.
H-W Wegen

Preliminary studies on cellulase production by selected Basidiomycetes and the effect of copper-chrome-arsenate on these enzymes
1980 - IRG/WP 1122
The growth of wood-destroying fungi on ligno-cellulosic materials depends on the production of many enzymes, of which probably the most important is the multi component cellulase system. Within this system, at least three different kinds of enzym are believed to be involved in crystalline cellulose decomposition. These are endo-1,4-glucanase, exo-1,4-ß glucanase and ß-glucosidase. Most of the recent research on cellulases has concerned isolation, purification and characterisation of the enzymes and their application in the utilisation of cellulosic waste. Information on the chemical inhibition of cellulases is available but there is little reference to the interaction of wood-attacking cellulases and the preservatives which are used to protect wood. The objective of this work is to study the production and activity of cellulases of selected basidiomycetes and to observe the effect of wood-preservatives on these enzymes. Preliminary studies with copper-chrome-arsenate (CCA) are reported here
O Collett

Natural durability transfer from sawmill residues of white cypress (Callitris glaucophylla). - Part 2: Laboratory fungal bioassays
2000 - IRG/WP 00-20204
Extracts from sawmill residues of the naturally durable white cypress, Callitris glaucophylla were tested for fungicidal activity in a series of laboratory bioassays. The effects of different extraction solvents, techniques and sources of material on the biocidal efficacy of the resultant extracts were evaluated. Soil jar decay tests were used initially however, contractual time constraints necessitated the development of a more rapid screening technique. A modified sapwood agar media was developed and found to be suitable for testing the extracts. It could be applied to other non-diffusible wood preservatives. Ground white cypress sapwood was impregnated with a range of concentrations of various extracts and gamma irradiated. The treated sterilised sawdust was suspended in water agar. The media were inoculated with a white rot, Lopharia crassa, or a brown rot fungus Polyporus verecundus. Growth of the isolates was monitored for four weeks, enabling dose responses to be accurately determined. Methanol was determined to be the most effective extracting solvent, and toxic threshold values of the methanol extracts were estimated. Fractions of the total extract were also compared. Most fungicidal activity was found in the most abundant fraction, which contained significant proportions of terpenes and other non-polar, low boiling point compounds.
M A Powell, L M Stephens, L Francis, M J Kennedy

Variation in infection rates of blue-stain, mould and white rot tropical fungi on mixed light Malaysian woods
2000 - IRG/WP 00-10334
The modified 3-week FRIM laboratory method for screening of anti-sapstain formulations against three representative tropical fungi causing blue-stain (Botryodiplodia theobromae), mould (Paecilomyces variotii) and white rot (Schizophyllum commune) infection of sapwood species was used to examine the relative resistance of the sapwood of eight mixed light Malaysian woods, Scots pine (Pinus sylvestris), medium density fibreboard produced from Rubberwood (Hevea brasiliensis) and the heartwood of Sentang (Azadirachta excelsa), to infection by these organisms. After 21 days it was found that Ramin (Gonystylus spp.), Rubberwood, Mersawa (Anisoptera sp.), Ludai (Sapium spp.), Yellow meranti (Shorea spp.), Scots pine and Jelutong (Dyera costulata) were highly susceptible to the pooled combinations of blue-stain, mould or white rot infection often sustaining >50% overall mean fungal coverage or when at least one of the infection types has reached maximum mean coverage (75.5%) of the wood samples. However, the Rubberwood-based fibreboard, and particularly Sentang, and the softwood Agathis spp. from Kelantan (trade name: Damar minyak) and Sarawak (trade name: Bindang), were relatively moderately susceptible to infection, sustaining between 9 and 47% overall mean fungal coverage after 21 days, or even considerably less susceptible (5 - 20% overall coverage) after 14 days. There was absence of both blue-stain and white rot fungal growth on all samples dipped in a low (0.03%/0.03%) fungicide concentration of a MBT/TCMTB anti-sapstain formulation. Such laboratory test results could have significant implications to field or industrial sapstain control of sapwood timbers concerning the lag time between tree felling and anti-sapstain treatment and seasoning.
A H H Wong, S Ahmad

Fungicidal efficacy of some dimethyldithiocarbamates, dymethylaminopropionitrile and some salts of S-substituted thioglycolic acid
1998 - IRG/WP 98-30180
Screening for fungicidal activity against Trametes versicolor and Coniophora puteana of the following compounds was performed: sodium N,N-dimethyldithiocarbamate, dimethylalkylammonium (C12-C14) N,N-dimethyldithiocarbamate, benzyldimethylalkylammonium (C12-C14) N,N-dimethyldithiocarbamate, N,N-dimethylaminopropionitrile and ammonium, copper and zinc salts of N,N-dimethyldithiocarbamoylacetic acid. The compounds were synthesised and delivered by UCB Chemicals, Ghent, Belgium. Potato dextrose agar was used as a nutrient medium. The strongest fungicidal activity against both fungi was exhibited by dimethylalkylammonium and benzyldimethylalkylammonium dimethyldithiocarbamates. They retarded mycelium growth already at a concentration of 1.0x10-4 mol/l and completely prevented the growth at 1.0x10-3 mol/l. The other compounds revealed lower fungicidal efficacy. The activity of dimethyldithiocarbamates and dimethylaminopropionitrile was determined also by a mini-block test method. Impregnated spruce wood mini-blocks were exposed to Coniophora puteana and beech wood mini-blocks to Trametes versicolor. In both cases, outcomes of the mini-block test confirmed the screening results.
M Petric, F Pohleven, M Humar, U Kolman

Screening results of fungicides for sapstain control on Pinus radiata
1983 - IRG/WP 3236
Thirty-two compounds were tested to determine their ability to contain the growth of stain, mould and rot organisms on fresh Pinus radiata D Don. A screening technique was employed using 35 to 50 mm diameter biscuits of Pinus radiata stemwood 10 mm thick. No compound was found to be cost effective when compared against the standard treatments of NaPCP (0.5% a.i.) plus borax (1.5%) and Captafol (0.2% a.i.). The best compound identified was a guanadine compound Guazatine which at 0.2% a.i. was slightly better than the standard treatments employed in New Zealand. From these results and previous published work it would appear that mixtures offer more hope of a low hazard, cost effective treatment to replace the presently used industrial standard.
P J Hayward, J Duff, W Rae

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