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The evaluation of synergistic effects of chemicals on fungicidal efficacy in crossed-paper tests
1991 - IRG/WP 2383
The mixing effects of wood preservatives were evaluated using the crossed-paper technique. Two filter paper strips (0.7 x 8 cm²) were treated by soaking with different chemicals [fungicides, a termiticide (chlorpyrifos or phoxim), a surface-active agent, a synergistic agent, and a stabilizer], and placed at right angles to each other on a fully grown mycelial mat of a test fungus in a Petri dish. When the four organoiodine fungicides were incorporated with chlorpyrifos or surface active agent, only 3-iodo-2-propynyl butyl carbamate (IPBC) showed the desirable synergistic effect against every wood-decaying fungus tested. Other fungicides did not always tend to produce the synergistic effect with the addition of a surface active agent. 4-Chlorophenyl-3-iodopropargyl formal (IF-1000) appeared to indicate an undesirable antagonistic effect when mixed with either chlorpyrifos or a surface active agent. 3-Bromo-2, 3 diiodo-2-propenylethyl carbamate (EBIP) did not show any synergistic action by mixing with chlorpyrifos and/or a surface active agent, although the fungicidal enhancement was induced satisfactorily by mixing the fungicide with chlorpyrifos, a stabilizer and/or a synergistic agent, especially against Tyromyces palustris and Coriolus versicolor. Similarity of the results obtained in the present investigation and in the previous laboratory decay tests leads to the conclusion that the crossed-paper technique is suitable for the evaluation of the mixing effect of chemicals on fungicidal efficacy.
Dong-heub Lee, K Tsunoda, M Takahashi


Evaluation of the leach resistance and preservative efficacy of novel biocides as surface treatments applied by brush to spruce (Picea abies)
1998 - IRG/WP 98-30170
The comparative leach resistance and preservative efficacy of a number of alternative organic preservatives (available from Zeneca Specialties) and selected commercially available biocides as surface coatings to wood in Hazard Class 3 have been assessed. Two concentrations of test preservatives were applied by brush to Spruce (Picea abies), including formulation and untreated controls. A leaching program was carried out involving the immersion of the treated blocks in water for a scheduled period of time. Blocks were then subjected to biological tests to determine preservative efficacy using the basidiomycetes Coniophora puteana and Gloeophyllum trabeum in a modified EN 113 system; sapstain and mould tests were separately undertaken according to a modified EN 152 test using mixtures of Aureobasidium pullulans and Sclerophoma pithyophila, and Trichoderma harzianum and Trichoderma saturnisporium. Of the four alternative actives tested, one Zeneca development product based on Hexaconazole compared very favourably against the selected commercial biocides tested. An aqueous system based on a Zeneca penetrating aqueous polymer coupled with the Zeneca development active demonstrated favourable performance in relation to an existing solvent based product.
I M Tierney, A Bruce, D C R Sinclair, T Yeates


An evaluation of CCA, CCB and CCP preservatives using a "sandwich test"
1991 - IRG/WP 2370
The last two years has seen some important changes in standards and preservative types used in Scandinavia, which have led to a wider choice for specifiers. In order to identify those treatments suitable for replacement or reinforcement of decayed constructional timbers, it was felt necessary to modify the standard EN 113 test. Impregnated blocks were sandwiched between two untreated blocks, previously infected with either Coniophora puteana, Poria placenta or Serpula lacrymans. The assemblies were exposed on a water -agar medium After which weight losses were determined. All treatment combinations resisted attack by Serpula, but CCP proved ineffective against Poria and Coniophora.
A P Koch, L B Sheard


Evaluation of the fire retardant efficacy and leach resistance of an amino resin fire retardant - Preliminary report
1983 - IRG/WP 3260
The Early Fire Hazard Indices of untreated Pinus radiata were determined by testing to Australian Standard 1530, Part 3 - 1976. Differences in the performance of heartwood and sapwood were noted, with heartwood samples giving higher Ignitability, Heat Evolved and Spread of Flame indices. The treatability of Pinus radiata with Pyrogard H was assessed, and backsawn sapwood treated more effectively than all other combinations of direction of cut and sapwood/heartwood. Treatment of kiln dried DAR Pinus radiata with Pyrogard H did not produce dimensional changes of practical significance. This factor, plus a high concentration gradient of retardant in the treated timber, make it an ideal treatment for fully machined and profiled Pinus radiata. The leach resistance of the retardant was assessed. A greater percentage of phosphorus than nitrogen was leached, but the retardant remaining after leaching conferred similar protection to the unleached material at equivalent rententions. Pyrogard H is an effective leach resistant fire retardant for Pinus radiata.
W D Gardner, P N Alexiou, P Lind, D Butler


An evaluation of the efficacy of a chlorothalonil formulation and a chlorothalonil plus chlorpyrifos formulation in the field
1993 - IRG/WP 93-30005
Details on the treatment of Pinus radiata D. Don and Eucalyptus regnans F. Muell. sapwood specimens to three retentions of each of two preservative formulations (chlorothalonil in oil; chlorothalonil plus chlorpyrifos in oil) and their installation below ground at three field test sites in Australia are given. Specimens were treated with each formulation to achieve 3.2, 6.4 and 12.8 kg/m³ of chlorothalonil a.i. and 3.2+0.2, 6.4+0.4 and 12.8+0.8 kg/m³ of chlorothalonil plus chlorpyrifos a.i. For comparison, specimens of each timber species, treated to a commercial in-ground retention of a copper-chromium-arsenic (CCA) formulation, were also installed. Treated specimens (including controls) have been scored for their condition annually for attack by subterranean termites and fungal decay using a scale ranging from 4 (sound) down to 0 (failed). After two years of exposure, mean termite and decay scores for replicate specimens at each site indicate that all three retentions of each formulation compare favourably with CCA.
J W Creffield, N Chew


Evaluation of the insecticidal efficacy of deltamethrin and the fungicidal efficacy of its association with TCMTB + MBT in the field of wood preservation
1986 - IRG/WP 1289 E
Deltamethrin possesses many advantages for the insecticidal protection of wood: relatively low toxicity, very reduced evaporation, very prolonged retention in the wood, very slight leaching after having penetrated the wood, and absence of odour. Its association with other active agents or solvents is being studied with regard to chemical compatibility. Compatibility studies have proved positive for azaconazole, TCMTB and MBT. The associaticn of 5 g/l deltamethrin + 50 g/l TCMTB + 50 g/l of MBT is used at a minimum rate of 5% for the preservation of freshly felled rough timber in tropical regions. With regard to insecticidal efficacy, the dilution of 0.025% deltamethrin is that considered effective for spraying in most applications. When the wood is not exposed to harsh weather conditions (sun), a dose of 0.0125% can be used, especially by steeping; at this preventive concentration, deltamethrin possesses a broad spectrum of action. The dose can be reduced even further against Hylotrupes bajulus.
J S Duguet


Proposal for a simple methodology for the evaluation of the preventive effectiveness of protectors applied in superficial treatments against basidiomycetes fungi
1999 - IRG/WP 99-20167
Due to the considerable effect that the relation between the lateral surface and the volume of wood blocks has on superficial treatments, this work has attempted to determine the ideal size which allows to evaluate the effectiveness of a preservative in the shortest possible time. Three wood blocks of different dimensions were tested. In addition, as it is necessary to neutralise the effect of the heads for superficial treatments, two kinds of sealant which are clearly affected by the size of the wood blocks (inert and active sealants), were also studied. Likewise, two kinds of superficial treatments (deeping and brushing) were analysed. The possible influence of the size and form of the wood blocks in preventive effectiveness was determined by the weight loss they suffered after 12 weeks of incubation on Gloeophyllum trabeum cultures in malt agar. As was expected, the results obtained showed the greatest degradation on smaller wood blocks. For this reason, larger wood blocks should not be used for tests of this kind, as these did not undergo significant weight loss under these two test conditions during the study. Regarding the sealant, it has been proved that inert sealant influences the fungi activity less than the active sealant. Finally, no differences as to the kind of superficial treatment were observed.
M T De Troya, A Navarrete, F Rubio, M Yuste, C Rodríguez-Borrajo, D Muñoz-Mingarro, F Llinares


Accelerated weathering test for the evaluation of wood preservative efficacy
2003 - IRG/WP 03-20262
Wood samples treated with ammonium copper quat (ACQ-1900 and ACQ-2200), Chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2 hours UV-light irradiation followed by water spray for 18 minutes. The changes on the surface of the weathered samples were characterized by FTIR Spectroscopy and color measurements on the samples with 0, 200, 400 and 600 hours of total weathering. The objective of this study was to investigate the changes created by weathering on impregnated wood with several different wood preservatives. This was performed study, accelerated weathering using UV irradiation and water spray was used to simulate natural weathering. FTIR and color measurement was used to investigate the changes after several intervals (0- 200 h- 400 h- 600 h) in artificial weathering of treated and untreated wood.
A Temiz, M Eikenes, Ü C Yildiz, F G Evans, B Jacobsen


Increased biological durability differs for traditional wood preservation and new non-biocidal systems (NBS)
2000 - IRG/WP 00-20212
Wood preservation is a way to increase the biological durability of wood by the addition of chemical components with a biocidal effect. The effect of such treatment is clearly concentration dependent. At distinct levels of fungicide concentration fungi are killed or inhibited in their enzymatic functioning to provide nutrients. The toxic limits allow decision-makers to provide treating prescriptions based on a teared approach of European standards. Non-biocidal treatments may act totally different. Mechanisms as moisture exclusion or hydrophobation and modification of wood components inhibit, retard or stop the colonisation by fungi. Though these treatments are only effective from certain levels on or when a certain degree of substrate modification is reached, it is hardly possible to establish a dose response curve. Since these treatments do not fit into the standard methodology for evaluation of traditional wood preservation either new test methods or at least new ways of judgement and interpretation of results are required.
J Van Acker, M Stevens


Insect growth regulators: modes of action and mode of action-dependent peculiarities in the evaluation of the efficacy for their use in wood preservation
1997 - IRG/WP 97-30155
Up to now, the insecticides used in wood preservation are either of more or less non-specific mode of action - like boron - or of neurotoxic mode of action - like chlorinated hydrocarbons, carbamates and pyrethroids. The active ingredients actually used are primarily mirroring the progress in active ingredient research in plant protection. The methods of testing of the insecticidal efficacy of wood preservatives are developed in the seventies when oil-borne preservatives with chlorinated hydrocarbon-insecticides of high penetration capabilities are dominating. So, the complete testing inventory was neurotoxintailored during this time and consequently topranking unconsciously this group of insecticides in the past. This type of topranking was decisive for the selection of the pyrethroids as replacement for the chlorinated hydrocarbon-insecticides and the rejection of the competing JHA's (WÄLCHLI & TSCHOLL 1975, TSCHOLL 1977) and molt inhibitors (DOPPELREITER 1980, CYMOREK & POSPISCHIL 1982) in the early eighties. The testing problems arising from the introduction of the molt inhibitors in wood preservation were not severe (PALLASKE et al. 1993, VALCKE & PALLASKE 1995), but it could be pointed out, that not the full bandwith of insecticidal properties is taken into account (GRAF 1995, PALLASKE 1995). This gap in test methodology gains more importance in the evaluation of the efficacy of hormon-analoga for their use in wood preservation and requires the modification of some standard test methods (GRAF 1996). A brief review of the modes of action of the "modern" insecticides like chitin synthesis inhibitors, juvenil hormone analoga and ecdysone mimics is given for highlighting the modifications required in testing repertoire and for pointing out the changes in valuation criteria requested for a correct and reliable valuation of preservatives with ovicidal mode of action.
M Pallaske


PXTS; A Metal Free Oligomer Wood Preserving System - A Summary of Data To Date
2004 - IRG/WP 04-30350
The world is continually looking for new wood preservative technology, especially to address environmental concerns. Recent changes in the USA have limited the use of arsenical containing formulations to industrial use through a negotiated voluntary cancellation of most residential label uses. PXTS (Polymeric Alkylphenol Polysulfide) offers a brand new technology that is an all organic system, like creosote or pentachlorophenol, but without the associated human toxicity. PXTS has been extensively tested and evaluated over the last 6+ years in both laboratory and field efficacy tests, and has undergone extensive physical and chemical property tests on both the active ingredient and on the PXTS treated wood . This paper summarizes the results of the testing on PXTS and PXTS treated wood through 2003. Lengthy field trials have now proven the efficacy of PXTS in both harsh and very severe test sites where attack is rampant from insects and decay organisms. Additionally, laboratory efficacy tests have shown that the PXTS performance profile is superior to creosote in many applications, extending the life of wood treated with PXTS many fold over that of untreated controls. Laboratory soft rot test indicate that PXTS may be as much as 6 times more effective than AWPA P-1/P-13 creosote. Tests in marine waters, although not presented here, have also proven PXTS superior to creosote in harsh Florida environments riddled with Limnoria. Although work is continuing on the evaluation of this new preservative, this document represents the most complete portfolio of information on PXTS presented to an international audience.
M H Freeman, D D Nicholas, D Renz, R Buff


Laboratory evaluation comparing three commercial termite baits based on chitin synthesis inhibitor (CSIs) against the subterranean termites Coptotermes acinaciformis (Froggatt) and Mastotermes darwiniensis Froggatt
2007 - IRG/WP 07-10625
This laboratory bioassay report describes laboratory evaluation undertaken to compare the efficacy, and palatability of Requiem®, Nemesis® and Sentricon® AG as candidate bait toxicants against the subterranean termites Coptotermes acinaciformis (Froggatt) and Mastotermes darwiniensis Froggatt. The laboratory bioassay results confirmed palatability and efficacy differences between the three commercial bait toxicants. Requiem® is the most palatable of the bait toxicants, while Nemesis® caused higher mortality rate with less bait substrate consumed.
B Ahmed


Preliminary evaluation of efficacy of copper in combination with boron and NHA (N'-N-(1, 8-naphthalyl) hydroxylamine) against wood decay
2008 - IRG/WP 08-30452
In this study, efficacy of various combinations of copper sulfate with either boric acid or calcium precipitating agent, NHA-Na (N'-N-(1, 8-naphthalyl) hydroxylamine) was evaluated. Wood specimens were treated with either 1%, 0.5%, or 0.1% concentrations of copper sulfate, boric acid, NHA-Na, copper sulfate + boric acid, or copper sulfate + NHA-Na mixtures. Treated specimens were subjected to laboratory decay resistance tests by using Petri dishes inoculated with Basidiomycetes fungi, Tyromyces palustris and Trametes versicolor for 12 weeks. Increased efficacy of copper sulfate against the brown rot fungus, T. palustris was observed when either boric acid or NHA-Na was added. NHA-Na only treatments at 1% and 0.5% concentration levels were the most effective treatments against the fungi tested. Boric acid treatments were not able to protect wood against decay after leaching because of possible leaching of boron. More detailed studies are in progress by using different fungal species and termites to obtain detailed information on efficacy of copper combinations with various compounds.
E Terzi, C Köse, S N Kartal


Evaluation of formulation type on the efficacy of bifenthrin as a glueline termiticide for veneer based wood products
2010 - IRG/WP 10-40486
Field trials were carried out in Australia on Coptotermes acinaciformis to evaluate the efficacy of various bifenthrin formulations. One trial tested plywood made by Zelam at their research facility in New Zealand and compared three emulsifiable concentrate formulations (EC), a suspension concentrate (SC) and an encapsulated formulation (CS). A second trial compared laminated veneer lumber (LVL) made at a commercial mill in New Zealand and compared EC and CS formulations. A third trial used LVL made at commercial mills in New Zealand and Australia and compared CS and SC formulations respectively. Trial results show zero attack on the engineered wood samples when glueline and surface applications were used. Glueline only treatments resulted in some surface grazing but no penetration into centre veneers. In all trials there was no significant differences in efficacy between the formulation types.
P Lobb, A Siraa


Evaluation of the Virulence of the Termite Species Occurring in the French Tropical Overseas Territories
2018 - IRG/WP 18-10913
The French tropical overseas territories are strongly affected by termites’ activity, which is especially devastating because the species encountered there are among the most virulent in the world. That is why in these regions it is particularly important that producers and users of wood-based products are provided with materials and preservative products whose durability and efficacy has been thoroughly tested and can be relied on. Specifically, the biocide actives used in wood preservatives and manufactured termite barriers available on the construction market need to demonstrate efficacy against the termite species in question and adequate performance in real-life situations of long-term use. Past studies have demonstrated that differences exist between particular species – especially between European and tropical termites – in terms of their sensitivity to biocidal treatment. These studies highlight the importance of testing preservative products and construction materials against the termite species which occur in the areas for which the products are intended. European and French standards have been initially developed for performing efficacy assessments on the Reticulitermes subterranean termites and so they cannot be used as such for testing against tropical subterranean termites and other groups of termites (drywood and tree termites). In view of this, clearly there is a need to amend the existing protocols and develop new, more suitable ones which will make possible effective testing of the resistance of various wood or non-wood based building materials to the tropical termites species present in the French overseas territories. The Viterdom project has two aims. One is to identify, for each territory concerned, the reference termite species that should be used in testing the relevant efficacy of wood preservatives and termite barriers and the durability of native wood species and wood-based materials. The other is to develop new test protocols that will allow us to determine the performance of both treated and untreated material in use.
M Kutnik, I Paulmier, J Vuillemin


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


Nondestructive Evaluation of Oriented Strand Board Exposed to Decay Fungi
2002 - IRG/WP 02-20243
Stress wave nondestructive evaluation (NDE) technologies are being used in our laboratory to evaluate the performance properties of engineered wood. These techniques have proven useful in the inspection of timber structures to locate internal voids and decayed or deteriorated areas in large timbers. But no information exists concerning NDE and important properties of wood composites exposed to decay fungi. For our pilot study on several types of wood composites, we examined the relationship between nondestructive stress wave transmission, decay rate and the bending properties of OSB exposed to the brown-rot fungus, Gloeophyllum trabeum (MAD-617). The following measurements were taken: stress wave transmission time (pulse echo test method), static bending test (ASTM D3043-95), and decay (expressed as percent weight). Stress wave measurements correlated with strength loss and with increasing rate of fungal decay. Stress wave NDE has great potential as a method for inspection of wood composite load-bearing (in-service) structures, detection of decay in laboratory tests, assessment of chemical additives to improve wood composite durability, and prediction of long term composite performance.
B Illman, V W Yang, R J Ross, W J Nelson


Field test evaluation of preservatives and treatment methods for fence posts
1985 - IRG/WP 3347
This work presents the field test results after fifteen years exposure of Eucalyptus saligna fence posts treated with six different preservatives and five treatment methods. All the combinations with oil-borne preservatives presented the best results and among the waterborne preservatives, the fence posts treated by immersion method were with the lowest performance in the field test.
G A C Lopez, E S Lepage


Evaluation of two populations of Reticulitermes santonensis De Feytaud (Isoptera) by triple mark-recapture procedure
1997 - IRG/WP 97-10237
The optimisation and use of biocides is linked to the improvement in our understanding of the target organism. With this in mind we have studied 2 populations of the termite Reticulitermes santonensis De Feytaud. The first inhabiting an urban territory, the trees lining Ave. Boutroux in Paris. The colony has been estimated at 1,200,000 +/- 130,000 insects by triple mark-recapture procedure, foraging a surface of 1080 m2. The area containing visible damages in the trees is of 2,100 m2. The greatest distance covered by an individual is 65 m in 18 days. The second is a field population at Fondette near Tours. The zone studied is of 2,500 m2, the colony being estimated at 230,000 +/- 14,000 insects, foraging a surface of 145 m2. The greatest distance covered by an individual is 40 m in 13 days. This study shows that a termite worker can cover a considerable distance in a short time and that the colonies themselves seem to move within a zone that they cannot totally exploit permanently.
I Paulmier, B Vauchot, A-M Pruvost, C Lohou, M Tussac, M Jéquel, J-L Leca, J-L Clément


Improved techniques designed for evaluation of fungicides in soil for control of dry rot fungus Serpula lacrymans
1985 - IRG/WP 2238
Improved techniques provide a laboratory method for the evaluation of chemicals in soil for control of dry rot fungus Serpula lacrymans. Results with their application to three chemicals were reported. These techniques are useful to eliminate chemicals lacking the necessary toxicity and weatherbility for dry rot control when the chemicals have been applied to the soil.
M Takahashi, K Nishimoto


Japan's comments on ISO/DIS 12583-1/2
1996 - IRG/WP 96-20100
The paper describes an accelerated field test for the evaluation of timber preservative formulations against subterranean termites. The method has been adopted by the South African wood preservation industry as a screening method for the approval of wood preservatives for use under SA conditions. The method which is based upon the fungal cellar test offers a rapid means of evaluating the comparative performance of new wood preservative formulations in an environment that accurately reflects field conditions.
P Turner, D Conradie


Protocol for evaluation and approving new wood preservative
1985 - IRG/WP 2159
M E Hedley, J A Butcher


The evaluation of permethrin for wood preservation
1977 - IRG/WP 3107
The toxicity of the synthetic pyrethroid permethrin (NRDC 143) to a range of wood destroying insects has been investigated. In tests using Hylotrupes bajulus, Anobium punctatum, Lyctus brunneus and Reticulitermes santonensis permethrin showed a similar order of toxicity to that of gamma-BHC. Although the toxicity of permethrin to adult Anobium punctatum was of the same order as that of gamma-BHC, the toxicity to larvae was rather lower. The implications of these results are discussed and it is concluded that, subject to further field evaluation, permethrin could provide an alternative to gamma-BHC and dieldrin in wood preservatives.
R W Berry


Proposed methodology for the assessment of safety indexes
1990 - IRG/WP 3562
Safety Indexes (SI)s are developped on the same concept as Efficacy Indexes (EI)s: EIs are retentions of wood preservatives (percentages of the critical values "efficacy") which are presumed efficient for a given biological class of risk. In the same way, SIs are retentions of wood preservatives (percentages of the critical values "safety") which are taken as acceptable for human health and the general environment. EIs and SIs as well are derived from different types of bioassays and related to objectives of quality which may be either regulatory or harmonized within the programmes of the Standard Committees (CEN TC/38 for example). Critical Values are characteristics of wood preservatives; EIs and SIs are characteristics of treated wood; they vary with the different classes of risks.
G Ozanne


Evaluation of new creosote formulations after extended exposures in fungal cellar tests and field plot tests
2000 - IRG/WP 00-30228
Although creosote, or coal tar creosote, has been the choice of preservative treatment for the railroad industry since the 1920s, exuding or "bleeding" on the surface of creosote-treated products has been one incentive for further enhancements in creosote production and utility (Crawford et al., 2000). To minimize this exuding problem, laboratories such as Koppers Industries Inc., USA, and Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Chemical and Wood Technology, Melbourne, Australia, have developed changes in processing of coal tar that produce distillates with fewer contaminants. This "clean distillate" is then used to formulate "clean creosote" as a preservative. These new, unique creosote formulations are being investigated as part of a program to enhance the use of regionally important wood species in the United States. Four retention levels of each of two new creosote formulations creosote, one pigment-emulsified creosote (PEC) and one creosote formulation that meets the AWPA Standard C2-95 for P1/P13 creosote (AWPA, 1995a), were applied to two softwood species and two hardwood species. Two laboratory procedures, the soil-block and fungal cellar tests (accelerated field simulator), were used to evaluate the four creosote formulations. These procedures characterized the effectiveness of the wood preservatives. The soil-block tests were used to determine the minimum threshold level of the preservative necessary to inhibit decay by pure cultures of decay fungi. In general, the soil block tests showed there was little difference in the ability of the four creosote formulations to prevent decay at the three highest retention levels as summarized in a previous report by Crawford and DeGroot (1996). The soil-block tests will not be discussed in this report. Fungal cellar tests expose treated wood to mixtures of soil-borne fungi that promote accelerated attack. Crawford and DeGroot (1996) discussed the evaluation of the creosote formulations after 17 months of exposure in the USDA Forest Service, Forest Products Laboratory (FPL), fungal cellar. At that point in time data from the fungal cellar tests showed that softwoods are protected better than hardwoods for all four formulations of creosote tested. This report will discuss exposure of the fungal cellar stakes upto 36 months. In addition, field stake tests are being used to verify service life of the new creosote formulations in vivo. Results from accelerated tests are indicative of field performance, but the correlation between laboratory and field results is still being investigated. Field stake tests are regarded as critical, long-term evaluations that provide results most directly related to the performance of treated products in service. In this study, we report on the performance of the creosote formulations after five years of exposure in field tests.
D M Crawford, P K Lebow, R C De Groot


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