IRG Documents Database and Compendium


Search and Download IRG Documents:



Between and , sort by


Displaying your search results

Your search resulted in 724 documents. Displaying 25 entries per page.


Options for accelerated boron treatment: A practical review of alternatives
1985 - IRG/WP 3329
Boron wood preservatives are almost exclusively applied by momentary immersion and block diffusion storage. Alternative techniques are described which can be used to accelerate boron treatment. Diffusion coefficients have been derived to define the acceleration of diffusion with increasing temperature. Schedules are described for pressure impregnation of green timber, involving steam conditioning, evacuation and alternating pressure method treatment. Timber Preservation Authority penetration and retention requirements can be met in approximately 4-5 h. The optimum schedule, however, included a 12 hour holding period between steaming and preservative treatment. A method of applying boron preservatives as a vapour is described, Trimethyl borate vapour reacts with wood moisture to form boric acid. The kinetics of this reaction, however, are very fast. This limits treatment to timber dried to very low wood moisture contents.
P Vinden, T Fenton, K Nasheri


Movement of boron from fused boron rods implanted in Southern pine, Douglas fir, red oak, and white oak timbers
1995 - IRG/WP 95-30061
This paper reports the distribution of boron from fused boron rods installed into six-inch (15.2 cm) square timbers of Douglas-fir, Southern Pine, red oak and white oak exposed aboveground. The composition and size of rods was: sodium borate and sodium borate-copper oxide (8.5 x 100 mm²); sodium borate-copper, sodium borate and boric oxide-copper oxide (12 x 76 mm²). The boric acid equivalent was roughly monitored by the curcumin/salicylic acid color test and the presence of copper was detected by the chrome azurol-S reagent. One year after installation of rods, movement of boron was determined by application of curcumin dye to increment cores removed at various distances from the site of boron rod installation. A portion of a sodium borate treated Southern Pine timber was also analyzed by spraying curcumin dye on sawed longitudinal and transverse sections. At 2 years, one foot sections were removed from all timber species, sawed as above, and boron and copper detection reagent sprayed on the sawed surfaces. Movement of copper from rods in all timbers was virtually nil. Both transverse and longitudinal movement of boron from rods was greatest in Southern pine which also had the highest moisture content. Movement of boron was next best in red oak. There was little movement of boron away from the rods in white oak and Douglas-fir.
T L Highley, L Ferge


Protection of OSB against termites by incorporation of different actives via glue line treatment
2008 - IRG/WP 08-30453
Different organic actives and zinc borate were incorporated into OSB during the manufacturing process to enhance the resistance against termites. Tests according to EN 117 revealed excellent performance of thiacloprid. Other organic actives such as permethrin might be effective when used in higher amounts. Zinc borate failed the test by far.
S Donath, P Spetmann, T Jaetsch, T Zahlmann


Effect of borate on uptake and efficacy of an anti-sapstain treatment
2005 - IRG/WP 05-30380
The potential for using borates to enhance uptake and efficacy of propiconazole-based anti-sapstain chemicals was assessed on ponderosa pine sapwood wafers. Borates had no consistent effect on either net solution absorption or propiconazole distribution in the wood. Even small amounts of borate, however, markedly improved the performance of propiconazole against fungal discoloration. These results are consistent with previous tests of borate addition to other fungicides and highlight the potential for using less expensive ingredients to boost the performance of more costly biocides.
Jianju Luo, Hua Chen, J J Morrell


Ten year field test with a copper-borate ground line treatment for poles
1993 - IRG/WP 93-30017
A wood preservative paste consisting of borax and copper naphthenate has been tested to determine its efficiency in protecting wood from decay fungi and insects. The paste was applied to polyethylene-backed wraps that were fastened to the below-ground portions of unseasoned southern pine pole stubs. After 4 years of exposure in Mississippi, the untreated control stubs were completely deteriorated. The below-grade portions of the treated stubs remained sound after nearly 6 years of exposure due to movement of copper and diffusion of the borate throughout the cross section. Borate and copper also moved vertically in the stubs and was present in sufficient amounts to protect sections of the stubs as high as 3 feet above grade. After 9 years of exposure, the below-grade portions of the treated stubs had limited areas of decay and no termite damage; the majority of the cross section remained sound. Wood analysis indicated that concentrations of borate in the sound areas were about 1/10 the estimated toxic threshold. A visual examination and push test indicated that the treated stubs continued to be protected at groundline after 10 years of exposure. It is hypothesized that the continued protection of the below-grade portions of the stubs against both decay fungi and subterranean termites is the result of copper-borate complexes that have formed in the wood.
T L Amburgey, M H Freeman


Treatment of wood-based panel products with volatile borate
1990 - IRG/WP 3616
The paper presents recent developments in the use of volatile borate esters for the preservative treatment of wood based board materials. Several advances on previous reports are discussed. In laboratory studies, treatment times of approximately ten minutes at 20°C on boards at equilibrium moisture content provided full penetration and retentions of 1% wt/wt boric acid. Biological tests have been conducted on a wide variety of boards treated by the vapour boron method. In all cases a retention of 0.7% wt/wt boric acid gave complete protection from decay. These results are considered with regard to parallel studies on solid wood by colleagues at the Forest Research Institute, Rotorua. The advantages of vapour boron treatment for wood based board materials are discussed.
P Turner, R J Murphy, D J Dickinson


Wood protection by surface treatment of two borate preservatives, TIM-BOR® and BORA-CARE®, for the formosan subterranean termite and eastern subterrean termite
1993 - IRG/WP 93-10044
TIM-BOR® (disodium octaborate tetrahydrate: DOT, Na2B8O134H2O) and BORA-CARE® (40% DOT in ethylene glycol) are two borate products marketed for treating wood in use by brushing or spraying onto the wood surface. The active ingredients presumably diffuse into wood by the 10-15% existing wood moisture. Few data, however, are available to demonstrate the diffusion rate. Su & Scheffrahn (1991) suggested that diffusion rate of BORA-CAREä is quite slow but may be enhanced by the moisture brought in by termites into wood. As there is an increasing interest in using these products for remedial control of subterranean termites, there is a need to understand how do they behave. The object of this study is to examined the termiticidal effects of borate surface-treated wood against the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Koller).
M Toroko, N-Y Su


Laboratory evaluation of borate formulations as wood preservatves to control the subterranean termite coptotermes acinaciformis (isoptera: Rhinotermitidae) in Australia
2001 - IRG/WP 01-30266
The termiticidal efficacy of Borocol (sodium octaborate tetrahydrate), boric acid, bore-ester-7 and tri- methyl borate was evaluated in laboratory bioassays against Coptotermes acinaciformis (Froggatt). Seasoned sapwood blocks of Pinus radiata D. Don, and Eucalyptus regnans (F. Muell) were impregnated with the various borate compounds. There were marked differences in mass loss and mortality rate of the termite used in the bioassay units for different boron retentions. After 8 weeks the result suggested that, borate was toxic to termites in laboratory bioassay even at 0.20% m/m BAE and caused significant termite mortality. However, termites were not deterred from attacking the borate treated timber at higher retentions of > 2.0% m/m BAE. These laboratory results indicated that the minimum borate treatment required to protect timber against termites attack and damage was > 1.0% m/m BAE.
B M Ahmed, J R J French, P Vinden


Durability of Wood Plastic Composites Relative to Natural Weathering and Preservative Treatment With Zinc Borate
2005 - IRG/WP 05-40316
Wood-Plastic Composites (WPCs) used for decking have experienced dramatic increases in North America, averaging 25% growth per annum since 1998. A key factor contributing to this growth has been the successfully communicated message that they are "virtually maintenance free". The common perception being that the wood fiber is completely encapsulated by the thermoplastic resin, minimizing the potential for moisture absorption and inhibiting attack by wood destroying organisms. Recent publications, however, have raised concerns about the durability of WPCs. These studies showed that wood particles close to the surface of WPC products can attain moisture levels high enough to facilitate the onset of decay. Other experiments have shown that preconditioning this material through accelerated laboratory weathering (QUV) or natural exterior exposure to the elements, yielded significant increases in moisture uptake relative to the unexposed samples. The ability of these materials to absorb moisture has been identified as a significant factor in evaluating decay susceptibility in these laboratory tests. We examined moisture uptake in large sized (low surface to volume ratio) and smaller cut (high surface to volume ratio) WPC samples and found a much greater and rapid water uptake in the smaller samples. A soil block decay test with commercially produced unweathered WPC’s resulted in weight losses of between 10-20% (20-40% wood component) in as little as four months time. Effects of exterior weathering on moisture uptake showed increased moisture in samples taken from WPC boards in the field at various locations for 1 to 2 years. A soil block decay test with unweathered and naturally weathered WPCs showed significantly high weight loses in samples that had been in an outdoor exposure in Valencia, Ca for 2 years. Samples from the same exposure test that had been treated with 1.0 or 2.0 % zinc borate showed almost no weight loss.
M E Mankowski, F M Ascherl, M J Manning


Evaluating the natural durability of native and tropical wood species against Reticulitermes flavip
2004 - IRG/WP 04-10539
Environmental pressures to eliminate arsenate from wood preservatives has resulted in voluntary removal of CCA for residential applications in the United States. A new generation of copper organic preservatives has been formulated to replace CCA for decking and in-ground applications but there is no guarantee that these preservatives represent a permanent solution to all related problems. Therefore, it is still necessary to evaluate alternative treatments, as well as naturally durable wood species, in order to be prepared for future changes in the field. In this study, six hardwoods and six softwoods have been evaluated for their ability to resist termite damage by Reticulitermes flavipes in a 4-week laboratory no-choice test. In addition, moderately resistant Douglas-fir and southern pine wood blocks were evaluated after treatment with copper borate, copper naphthanate, and N,N-naphthaloylhydroxylamine (NHA). Erisma, juniper, ipe and white-cedar were shown to be highly resistant. NHA protected Douglas-fir and southern pine as effectively as copper borate or copper naphthanate. These results suggest that some naturally durable wood species, both tropical and native, can inhibit R. flavipes as effectively as preservative treatment.
R A Arango, F Green III, K Hintz, R B Miller


A chemical and mycological evaluation of fused borate rods and a borate/glycol solution for remedial treatment of window joinery
1983 - IRG/WP 3225
The possibility of using fused borate rods (Impel Borpatron) and a borate/glycol solution (Boracol-40) for depot impregnation of window joinery has been examined in a co-operative project between The Swedish Forest Products Research Laboratory, The Swedish University of Agricultural Sciences and Prolignum AB. The fused Impel rod is a glassy rod composed of disodium octaborate which readily dissolves and is distributed as bore acid when introduced into moist timber. Boracol-40 is a liquid containing disodium octaborate dissolved in glycol which has an ability to disperse in timber with a moisture content below 25%. The study involved treatment of a large number of windows in service as well as chemical and biological laboratory tests on the distribution and protective effect of the preservatives. In the field study about 100 windows, selected at random in various buildings in the Stockholm and Gothenburg areas were treated in-situ.
M-L Edlund, B Henningsson, A Käärik, P-E Dickèr


Chemical evaluation of borate treated pine sapwood attacked by the subterranean termite Coptotermes acinaciformis
1993 - IRG/WP 93-20003
Sapwood of hoop (Araucaria cunninghamii Ait. ex D. Don) and slash (Pinus elliottii Englem.) pines were treated by Vacuum Pressure Impregnation (VPI) to provide test specimens. The concentration of boron was defined by chemical analyses of the timber, in the zone of primary attack by the termite being bioassayed. A common method of definition of preservative retention, weight uptake of preservative fluid of known concentration, was compared to the chemical assay method for slash pine treatments. Analyses of gradient zones reflect the variable concentration of boron within test specimens. The test specimens were exposed to field termite colonies in a clear of ground completely protected from weather and wetting situation. Termite response was determined by mass loss over 5 weeks and modelled.
A R Moffat, B C Peters


Interim report on the use of borate rods for the in-situ treatment of joinery
1980 - IRG/WP 3159
In the U.K. in recent years, it has been recognised that there is a major need for in-situ treatment of joinery at risk from or showing the early signs of decay. Several techniques have been developed to provide such a treatment, one of which is based on the insertion of anhydrous borate glass rods. The tests in hand are long term and this report is confined to the mycological isolation data from Western Hemlock doors and as such is an interim report of current research.
D J Dickinson


Remedial ground-line treatment of CCA poles in service. Results of chemical and microbiological analyses 6 months after treatment
1986 - IRG/WP 3388
CCA-treated poles in service with incipient internal soft rot were remedially treated by inserting borate rods, brushing with a boron/glycol solution and injecting boric acid paste, copper/creosote paste or a commercial product (DFCK paste). The spread of active chemicals in the treated zone as well as the change in microflora have been studied with time. After six months chemicals had spread to most parts of the pole in the ground-line zone and the microflora had been changed - in some cases drastically. The test is still in progress. Chemical and microbiological analyses after 12, 28 and 60 months will be published at a later date.
B Henningsson, H Friis-Hansen, A Käärik, M-L Edlund


Performance of borate-treated sill plates (dodai) in a protected, above-ground field test in Japan
2002 - IRG/WP 02-30278
This document is supplemental to the previous IRG document (IRG/WP 2000-30239). An experiment to simulate the dodai (sill plate) of the Japanese houses was conducted at the termite field test site of the Wood Research Institute in Kagoshima, Japan where two economically important subterranean termite species [Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe)] are established. DOT(disodium octaborate tetrahydrate)-treated hem-fir samples [Tsuga heterophylla (Raf.) Sarg. and Abies amabilis (Dougl.) Forbes]- 105 x 105 x 400 mm in size were placed on concrete blocks 19 cm the above ground surface. The test samples were prepared from sound wood samples pressure treated to supply 10 replicates of shell-treated materials at target levels of 2% BAE and 3% BAE. The subsequent diffusion storage produced another set of through-treated samples at the same target levels. Feeder stakes within the block hollows extended into the soil to facilitate the access of the termites to the wood samples. The assembled sets were covered with plastic boxes to protect the samples from the weather. Samples were annually inspected for termite attack and decay and visually rated according to AWPA standards since installation on December 21, 1995. After 6 years’ exposure, one or two samples from each group of borate treatments (2% BAE shell, 3% BAE shell, 2% BAE through and 3 % BAE through treatments) were very slightly attacked by termites, though these treatments were free from termite attack for the first 5 years. Over the same period, slight termite attack was observed on the samples of 2% BAE plus DDAC (didecyldimethylammonium chloride) and CCA 4.0 kg/m3 treatments, the latter included as a reference preservative. Untreated hem-fir and hinoki (Chamaecyparis obtusa Endl.) controls showed progressive termite attack starting in the first year and were moderately to heavily attacked after 6 years’ exposure. Incipient decay was first found on 7 untreated hem-fir and sapwood portion of two untreated hinoki during the 5th year of exposure. Decay on the untreated controls progressed in the 6th year as expected.
K Tsunoda, A Adachi, A Byrne, P I Morris, J K Grace


Resistance of borate-treated lumber to subterranean termites in the field
1998 - IRG/WP 98-10255
Borate-treated wood samples were tested for their resistance against subterranean termites in the field. Wood samples (10.5x10.5x40cm3) of western hemlock were pressure impregnated with disodium octaborate tetrahydrate (DOT) and didecyldimethylammonium chloride (DDAC), and assigned into two groups on the basis of boron contents:high retention (1.5-2.2%BAE) and low retention(O.7~1.3%BAE). Eight replicates were prepared for each retention level. Four untreated controls were also included in the field evaluation for comparison. Each sample was placed on a concrete block 19cm above ground surface and covered with plastic box in Kagoshima, Japan on July 1, 1993. Four boxes were employed so that 5 samples (two each of treated groups and one untreated sample) were in each box. After two years of exposure, three of all the treated samples exceptionally sustained very slight attacks, while in general untreated controls were moderately to severely attacked. Borate-treatment was proved to be satisfactorily effective in protecting lumber in above ground situations from subterranean termites. Further trials have been set up to determine the long-term efficacy of the treatment compared to chromated copper arsenate treated and naturally durable wood.
K Tsunoda, A Adachi, T Yoshimura, A Byrne, P I Morris, J K Grace


Laboratory Evaluation of the Formosan Subterranean Termite Resistance of Borate-treated Rubberwood Chipboard
2004 - IRG/WP 04-30359
Both no-choice and two-choice 4-week AWPA laboratory tests were performed to evaluate the resistance of borate-treated rubberwood (Hevea brasiliensis) chipboard prepared from a commercial mill run, against the Formosan subterranean termite Coptotermes formosanus. Boric acid (technical granular) was incorporated into the boards during manufacture to achieve loadings of 1.0% or 1.1% boric acid equivalents (BAE). In the no-choice test, both the untreated chipboard and solid rubberwood controls sustained heavy termite attack (respective mean visual ratings of 4.6 and 2.7 on a 10-point AWPA scale), while the two retentions of borate-treated chipboard showed only light grazing (mean rating 9.2). The two-choice test demonstrated a preference of termites for solid rubberwood (mean rating 2.4) instead of untreated chipboard (rating 8.4), and for untreated (mean rating 8.4 and 8.8) instead of borate-treated (mean ratings 9.8 & 9) chipboards. Complete termite mortality in the presence of borate-treated chipboard in both laboratory tests demonstrates the toxicity of borates to Formosan subterranean termites.
A H H Wong, J K Grace


Resistance of borate-treated lumber to subterranean termites under protected, above-ground conditions
2000 - IRG/WP 00-30239
An experiment to simulate the dodai (sill plate) of the Japanese houses was conducted at the termite field test site of Wood Research Institute in Kagoshima, Japan where two economically important subterranean termite species [Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe)] are established. DOT(disodium octaborate tetrahydrate)-treated hem-fir samples [Tsuga heterophylla (Raf.) Sarg. and Abies amabilis (Dougl.) Forbes] in a dimension of 105 x 105 x 400 mm3 were placed on concrete blocks 19 cm above ground surface. The test samples were prepared from sound wood samples pressure treated to supply 10 replicates of shell-treated materials at target levels of 2% BAE and 3% BAE. The subsequent diffusion storage produced another set of through-treated samples at the same target levels. Feeder stakes within the block hollows extended into the soil to facilitate the access of the termites to the wood samples. The assembled sets were covered with plastic boxes to protect the samples from the weather. Samples were visually inspected for termite attack and decay and rated according to AWPA standards. After 4 years' exposure, borate-treated samples (2% BAE shell, 3% BAE shell, 2% BAE through and 3% BAE through treatments) were free from termite attack, while one replicate each of 2% BAE with DDAC (didecyldimethylammonium chloride) and CCA 4.0 kg/m3 treatments, the latter included as a reference preservative, were slightly attacked. Untreated hem-fir and hinoki (Chamaecyparis obtusa Endl.) controls were slightly to heavily attacked during the same test period. No sign of decay was found on any sample, although moisture contents were well above fiber saturation points in some samples.
K Tsunoda, A Adachi, T Yoshimura, A Byrne, P I Morris, J K Grace


Preservative treatment of green timber by soaking in ammoniacal copper borate
1984 - IRG/WP 3292
Freshly sawn boards of radiata pine sapwood were preservative treated by soaking in ammoniacal copper borate. Optimum schedules were obtained by partially seasoning the boards for one week prior to treatment. This aided the absorption of preservative and reduced the required soaking time to approximately 2 hours. Complete boron penetration was obtained after one week of block storage under cover and air drying. Copper penetration was more limited because of fixation of copper. The preservative treatment system should have particular application in the treatment of coconut timber destined for above-ground use but exposed to the weather.
P Vinden, A J McQuire


Accidental mold/termite testing of high density fiberboard (HDF) treated with borates and N’N-naphthaloylhydroxylamine (NHA)
2003 - IRG/WP 03-10462
High density fibreboard (HDF) was made from beech and pine furnish (50:50) and treated with boric acid (0.1-3%), borax (0.1-3%) or N'-N-(1,8-naphthalyl) hydroxylamine (NHA) (0.1-1%) prior to gluing with urea formaldehyde (UF) resin in order to determine resistance to Eastern subterranean termites (Reticulitermes flavipes Kollar), the most economically important termite species in North America. HDF and southern yellow pine (SYP) sapwood specimens were tested in a modified no-choice soil-block test normally used for fungal decay tests for 5 weeks. Within the first week of incubation, all HDF specimens were heavily overgrown with a variety of mold fungi. This same contamination was not seen in regular SYP specimens tested under the same conditions. Mold contamination did not appear to inhibit termite attack in any measurable way. Weight loss in control HDF specimens was 28% after 5 weeks while weight loss in control SYP was 12% under similar test conditions. Selected treatments with boric acid, borax, didecyl dimethyl ammonium chloride (DDAC) and NHA reduced termite attack in HDF and SYP specimens below 5% weight loss. Synergy was not observed for boron containing compounds and NHA. We conclude that i) soil contact accelerates HDF mold contamination and termite damage in the absence of termidicides ii) HDF made with UF is more susceptible to moisture acquisition and mold contamination than SYP iii) NHA does not act as a mildewcide iv) 3% borates retard both mold and termite damage; and v) HDF is less durable, and requires more preservative to protect, than SYP.
S N Kartal, H H Burdsall Jr, F Green III


Performance of borate-treated lumber in a protected, above-ground field test in Japan
2004 - IRG/WP 04-30344
This document is supplemental to the previous IRG document (Tsunoda et al., 2002). An experiment to simulate the sill plate (dodai) of the Japanese houses was conducted at the termite field test site of the Wood Research Institute in Kagoshima, Japan where two economically important subterranean termite species [Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe)] are established. DOT(disodium octaborate tetrahydrate)-treated hem-fir samples [Tsuga heterophylla (Raf.) Sarg. and Abies amabilis (Dougl.) Forbes]- 105 x 105 x 400 mm in size were placed on concrete blocks 19 cm the above ground surface. The test samples were prepared from sound wood samples pressure treated to supply 10 replicates of shell-treated materials at target levels of 2% BAE and 3% BAE. The subsequent diffusion storage produced another set of through-treated samples at the same target levels. Feeder stakes within the block hollows extended into the soil to facilitate the access of the termites to the wood samples. The assembled sets were covered with plastic boxes to protect the samples from the weather. Samples were annually inspected for termite attack and decay and visually rated according to AWPA standards since installation on December 21, 1995. All treated samples still remained free from decay after 8 years’ exposure, although slight progress in termite attack was observed on a few samples of 5 treatments within the last two years. Three samples with a target retention of CCA 4 kg/m3 were slightly attacked. On the other hand, 3% BAE through treatment performed best with mean rating of 9.8 against termite attack. After 8 years’ exposure, 2-4 samples from each group of borate treatments (2% BAE shell, 3% BAE shell, 2% BAE through and 3 % BAE through treatments) were slightly attacked by termites. Untreated hem-fir and hinoki (Chamaecyparis obtusa Endl.) controls showed progressive termite attack starting in the first year and were heavily attacked after 8 years’ exposure. Incipient decay was first found on 7 untreated hem-fir and sapwood portion of two untreated hinoki during the 5th year of exposure, whereas 9 and 4 sustained slight to heavy decay after 8 years’ exposure, respectively.
K Tsunoda, A Byrne, P I Morris, J K Grace


Borate diffusion from fused borate rods in douglas-fir transmission poles
1994 - IRG/WP 94-30042
Pressure-treated utility poles have given many years of excellent service, but their lifetime is often shortened by internal decay of the untreated heartwood center, particularly in refractory species, such as Douglas-fir. This paper reports the distribution of boron from fused borate rods installed in CCA-treated Douglas-fir transmission poles. The boric acid equivalent was roughly monitored by the curcumin/salicylic acid color test on increment cores removed from poles at 6 and 18 months after installation of fused borate rods. The percent of increment core length showing boron at 18 months was 2.5 times greater than at 6 months. Boron was almost always detected downward from the treatment at a distance of 25 cm (10 inches). Movement of boron upward from treatment holes was not as good, rarely exceeding 5 cm (2 inches). The increment core length showing boron did not always correlate with moisture content but when the moisture content was greater than 40%, the total core length with boron was greater than 80%.
T L Highley, W Finney, F Green III


Borate Protection and Termites: Variation in Protection Thresholds Explained
2006 - IRG/WP 06-20324
Laboratory and field data reported in the literature are confusing with regard to ‘adequate’ protection thresholds for borate timber preservatives against subterranean termites. The confusion is compounded by differences in termite species, timber species and test methodology. Laboratory data indicate a borate retention of 0.5% mass/mass (m/m) boric acid equivalent (BAE) would cause > 90% termite mortality and restrict mass loss in test specimens to 5%. Field data generally suggest that borate retentions appreciably in excess of 0.5% m/m BAE are required. We report a field experiment with varying amounts of untreated feeder material in which Coptotermes acinaciformis (Froggatt) responses to borate-treated radiata pine (Pinus radiata D.Don) were measured. In the absence of untreated feeder material, retention of 0.5% BAE provides adequate protection from Coptotermes sp., whereas in the presence of untreated feeder material, increased retentions are required. Furthermore, the retentions required increase with increased amounts of susceptible material. The apparently conflicting results between the laboratory and the field data are explained by the presence or absence of untreated feeder material in the test environment. Further investigation to determine how widespread this phenomenon is with different timber preservatives is suggested.
B C Peters, C J Fitzgerald


Performance of borate-treated lumber in a protected, above-ground field test in Japan
2006 - IRG/WP 06-30395
This document is supplemental to the previous IRG document (Tsunoda et al. 2004). An experiment to simulate the sill plate (dodai) of the Japanese houses was conducted at the termite field test site of the Research Institute for Sustainable Humanosphere of Kyoto University in Kagoshima Pref., Japan where two economically important subterranean termite species [Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe)] are established. DOT(disodium octaborate tetrahydrate)-treated hem-fir samples [Tsuga heterophylla (Raf.) Sarg. and Abies amabilis (Dougl.) Forbes]- 105 x 105 x 500 mm in size were placed on concrete blocks 19 cm above the ground surface. The test samples were prepared from sound wood samples pressure treated to supply 10 replicates of shell-treated materials at target levels of 2% BAE and 3% BAE. The subsequent diffusion storage produced another set of through-treated samples at the same target levels. Feeder stakes within the block hollows extended into the soil to facilitate the access of the termites to the wood samples. The assembled sets were covered with plastic boxes to protect the samples from the weather. Samples were annually inspected for termite attack and decay and visually rated according to AWPA standard since installation on December 21, 1995. All treated samples still remained free from decay after 10 years’ exposure. In contrast, slight progress in termite attack was observed on a few treated samples within the last two years. Four samples with target retention of CCA 4 kg/m3 were slightly attacked with mean rating of 9.6 against termite attack after 10 years. This meant that the extent of termite attack did not develop after the first attack. Through treatment at 3% BAE performed as well as CCA 4 kg/m3 after 10 years with mean rating of 9.5. Although mean ratings of termite attack on the treated samples ranged from 8.8 to 9.6, statistical analysis showed no significant differences among all treatments. Untreated hem-fir and hinoki (Chamaecyparis obtusa Endl.) controls showed progressive termite attack starting in the first year and were heavily attacked after 10 years’ exposure. Decay was found on 9 and 6 untreated hem-fir and hinoki, respectively.
K Tsunoda, A Byrne, P I Morris, J K Grace


Treatment of Green Logs infested by Exotic Pest: Case Study of the Emerald Ash Borer: Agrilus planipennis Fairmaire
2007 - IRG/WP 07-10628
Invasive alien insect species periodically infest forests in the United States causing the destruction of plant species and decimating populations, resulting in significant economic and ecological losses for areas involved. The Emerald Ash Borer (EAB) was first discovered on North American soil in the summer of 2002 near Detroit, Michigan and has since spread to several other Midwestern states and Ontario, Canada, causing the destruction of ash populations. Limitations posed on the circulation of green ash logs and lumber has seriously affected the economic value of ash logs and lumber in affected regions. This study investigated over bark chemicals and non-chemical treatments for sanitization of infested logs to allow free circulation and trade for value added products. Chemical treatments included borate with concentrations ranging from 5% to 16.5% (Boric Acid Equivalent) and Imidacloprid with concentration ranging from 0.005 to 0.02% applied as spray. Non chemical methods included treatments in conventional kiln and microwave at 50°C, 55°C, 60°C and 65°C. Results obtained showed that Imidacloprid treatments concentrations of 0.01% and above were effective at sanitizing infested logs. Borate treatments resulted in significant reduction in insect emergence in indoors rearing conditions but did not achieve full control of the insect infestation. For non-chemical treatments, kiln temperatures of 65ºC were successful for sanitization of infested logs. Microwave treatments were not as effective as conventional heat for controlling insect emergence, and we hypothesized that this was due to the uneven distribution of the heat inside the microwave used in the study. Approaches to improve the microwave treatment are proposed.
P Nzokou, S Tourtellot, D P Kamdem


Next Page