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Wood preservation in Poland
2004 - IRG/WP 04-30362
Dynamic growth of market demand for wooden elements and articles, generated in Poland increase of interest in industrial preservation. Today, Poland is a substantial producer and exporter of wood made products. Majority of exported wood - approximately 70% - is scotch pine (Pinus silvestris L.), which, due to its natural durability, requires preservation.
A Kundzewicz


In search of alternative antisapstain chemicals for use in Papua New Guinea
1988 - IRG/WP 3472
The paper presents results of antisapstain field trials from three locations in Papua New Guinea as part of the Research Centre's programme to find suitable antisapstains to replace the hazardous sodium pentachlorophenate. Effectiveness of seven tested chemicals varied between indigenous pines (Araucaria cunninghamii, Araucaria husteinii) and white coloured hardwoods (Alstonia scholaris, Pterocymbium beccarii) but not between sites. The indigenous pines required lower chemical concentration for same level and period of protection than white coloured hardwoods like amberoi and white cheesewood. Period of protection ranged from four weeks to a maximum of 16 weeks depending on chemical concentration and species of timber. Potential chemicals recommended for use as antisapstain include Celbrite T, Busan 1009, Penacide and Woodguard E.S. and Woodguard E.C.
A Oteng-Amoako


Selective adsorption of antisapstain actives from two aqueous suspensions, and movement of actives into wood
1996 - IRG/WP 96-30103
Green-off-saw rough sawn Pinus elliottii (slash pine) boards were dipped in aqueous suspensions of two antisapstain formulations, NeXgenâ and Busanâ Sap Stain Preventative (Busan 1009), at three product concentration levels. Concentrations of active ingredients (NeXgen: CTL (chloro-thalonil) and MTC (methylene bisthiocyanate); Busan 1009: TCMTB (2(thiocyanomethylthio)-benzothiazole) and MTC) were monitored with respect to the amount of material dipped. Selective adsorption (removal of actives from the suspension at greater than simple volumetric transfer rates) varied with formulation and active ingredient, and increased with decreasing product concentration. Movement of active ingredients into dipped boards was monitored for 30 days after dipping. Mobility order was MTC >> TCMTB > CTL. Surface depletion characteristics were obtained for each active ingredient.
M J Kennedy, T L Woods


Relationship between stacking, location and antisapstain preservatives on visible degrade of Eucalyptus regnans and Pinus radiata boards
1999 - IRG/WP 99-20162
An antisapstain trial was established at a Eucalyptus hardwood sawmill in Victoria, Australia. The trial incorporated two commercial formulations of antisapstain preservatives, used at four different concentrations on both hardwood (Eucalyptus regnans F. Muell) and softwood (Pinus radiata D. Don) boards. The trial also utilised different stacking methods (block-stacked, sticker-stacked, and block-stacked and wrapped in black plastic) and included replicates placed both outside in the drying yard, and inside under cover from the elements. The variation in stacking methods and in location was used to provide a variation in the fungal hazard. Worst degrade (mean of 83% at 36 weeks) was obtained for the hardwood block-stacked outside and wrapped in black plastic. Lesser extents of degrade were obtained for sticker-stacked hardwood outside (4.3%) and sticker-stacked hardwood under cover (1.2%). Degrade of softwood was less than that of hardwood under all conditions. Statistical analysis of the trial indicated that the probability of any individual hardwood board deteriorating outside was nearly 4 times greater than for a board kept undercover. In addition, the probability of degrade of a hardwood board which was block-stacked and wrapped in black plastic was 3.4 times that of a hardwood board which was block-stacked but not wrapped, which in turn was 10 times that of a hardwood board which was sticker-stacked. The probability of degrade in untreated hardwood timber was 20 times that of degrade in preservative-treated hardwood timber, with variations in preservative concentration having an insignificant effect. Over all conditions the probability of hardwood timber deterioration was 5 times that of the softwood. The results of this trial confirmed that timber stored closely stacked and under poorly ventilated conditions suffered a higher visible degrade, as expected for sapstain fungi. However, although preservatives effectively reduced visible degrade under all storage conditions and at all concentrations tested, selection of correct storage conditions was also an important part of minimising degrade.
J Snow, P Vinden, S M Read


New technique for inoculation of wood wafers with fungi
1997 - IRG/WP 97-20113
A pilot study is described for determining the best possible method for inoculating fungi onto the surface of wood wafers for sapstain control studies. Direct inoculation and spray inoculation are compared on water soaked and malt extract broth soaked wood wafers. The best growth of fungal hyphae across the surface of the wood wafers was achieved following spray inoculation onto malt extract broth soaked wood wafers.
J Snow, P Vinden


Effects of timber surface properties and dipping conditions on uptake of antisapstain actives from two aqueous suspensions, and ultimate effects on efficacy against mould and staining organisms
1995 - IRG/WP 95-30073
Green-off-saw rough sawn Pinus elliottii (slash pine) boards were dipped in aqueous suspensions of two antisapstain formulations, and the resultant surface retentions of active ingredients MTC (methylene bisthiocyanate), CTL (chlorothalonil) or TCMTB (2(thiocyanomethylthio)benzothiazole) were monitored by chemical analysis. Surface retentions increased with suspension concentration and surface roughness, and decreased with initial timber moisture content. Dipping time beyond 20 seconds, timber basic density and earlywood content had little effect. Relatively low surface retentions, produced by dipping smoother boards with higher initial moisture contents, provided lower protection against mould and stain during seasoning than higher retentions. Equations describing the effect of surface retention on efficacy were developed for both formulations, and retentions providing complete protection under the conditions of the test were determined.
M J Kennedy, T L Woods


The Role of Coformulants in Preventing Bacterial Biotransformation of IPBC
2002 - IRG/WP 02-10436
The inhibitory effects of disodium tetraborate decahydrate and benzalkonium chloride (BAC), two common coformulants of IPBC in antisapstain treatments, on an IPBC-transforming enterobacterial isolate ‘W1’ were determined by their effect on the specific growth rate constant in vitro. The IC50s of IPBC, BAC and borate were found to be 0.46, 0.026 and 5.7 mM respectively. The IC50 of the Arch antistain product AntibluTM Select was 0.024 mM, based on its BAC content. Although their IC50’s were significantly different, it was clear that the vast majority of the bacterial toxicity of the AntibluTM Select was due to its BAC content. The degradation of 0.4 mM IPBC by the bacterium W1, as measured by the accumulation of its degradation product, iodide, in liquid culture, was completely inhibited by BAC concentrations greater than 18 μM, and the toxicity of the spent culture medium to Aspergillus niger, as measured by an antibiotic assay disc assay, was not ameliorated above this concentration. Below 18 μM, the toxicity of the spent broth was significantly reduced, and the accumulation of iodide occurred rapidly. Demonstrating the toxicity of BAC to bacteria, and its consequent inhibition of IPBC degradation in vitro, are indicative of the importance of coformulation in controlling bacteria that might otherwise cause preservative loss, and of their significance in determining the ultimate environmental fate of cobiocides.
S R Cook, D J Dickinson


Generic code of good practices for wood protection facilities. Part 1: Wood protection (antisapstain) facilities
1993 - IRG/WP 93-50003
In general, the potential of high toxicity (aquatic and human) of wood protection (antisapstain) chemicals dictates the need to protect the environment and humans from its harmful effects. This document is a compendium of recommendations for the design and operating practices of wood protection facilities. The suggested recommendations focus on achieving the objectives of protecting the environment and workers in a wood protection facility from harmful exposure to wood protection chemicals.
G Das, V N P Mathur


Effectiveness of a newly registered antisapstain preservative in preventing stain of Eucalypt timber in Australia
2000 - IRG/WP 00-30229
An antisapstain trial was conducted on two sites (Alexandra and Trentham) in order to establish the concentration of a newly registered antisapstain preservative (consisting of benzalkonium chloride (BAC) & 3-iodo-2-propynyl butyl carbamate (IPBC) & disodium octoborate (boron)) needed to prevent stain of Eucalypt timber. After 20 weeks of exposure at the Trentham site, the water treated boards had a mean fungal degrade of 98.8%. Those boards treated with the BAC & IPBC & boron at 1.5, 2.25 and 3.5% had a mean degrades of 31, 10.4 and 12% respectively. Boards treated with DDAC & IPBC 1% had a mean degrade of 18.8% at 20 weeks exposure. After 8 weeks exposure at the Alexandra site, the water treated boards had a mean fungal degrade of 75%. Those boards treated with the BAC & IPBC & boron at 2.25% had a mean degrade of 10.8%. BAC & IPBC & boron at all concentrations tested at both locations was effective in preventing the stain found on the control (water treated) boards after 8 and 20 weeks exposure.
J Snow, P R S Cobham, N Ryan


Sentry®, a new antisapstain formulation for protecting logs and lumber. - Part 2: protection of lumber
1999 - IRG/WP 99-30189
Recent research conducted by Forest Research, Chemcolour Industries (NZ) Ltd. and Fletcher Challenge Forest Ltd. has resulted in the development of antisapstain formulations that meet the efficacy requirements of the New Zealand Forest industry for export logs. One treatment, called Sentry®, is now poised for commercial use in New Zealand for treating export logs, having undergone an extensive suite of field and mill trials over a two year period. This paper presents results of field trials set up to determine the efficacy of Sentry® on block stacked radiata pine. Sawn timber was collected from a local mill, sawn into 1 meter lengths, dipped in antisapstain solution, and block stacked prior to assessment of surface fungal degrade after 6, 12 and 15 weeks over a period including a severe hazard New Zealand summer. The higher concentrations of the commercial standards were required to achieve adequate protection of block stacked radiata pine in storage for 12 weeks. After 12 weeks, Sentry®, at the lowest concentration tested (equivalent to 0.125% methylene bis thiocyanate (MBT) plus 0.025% 2-n-octyl-4-isothiazolin-3-one (isothiaz.), gave equivalent protection to the highest concentrations of all the commercial standards (0.6% 3-iodo-2-propynyl butyl carbamate (IPBC) plus 4.8% didecyldimethyl ammonium chloride (DDAC); 0.15% carbendazim plus 0.15% copper-8-quinolate (Cu-8): 0.6% MBT plus 0.6% chlorothalonil). The high level of protection achieved by Sentry® was in part attributed to the broad spectrum of fungicidal activity offered by MBT plus isothiaz. and the micro-emulsion system used.
R N Wakeling, D R Eden, C M Chittenden, J G Van der Waals, B Carpenter, I Dorset, R Kuluz, J Wakeman


Laboratory evaluation of potential antisapstain treatments for Pinus radiata
1983 - IRG/WP 3237
Twelve formulations were tested in the laboratory using a 'mini' board test for effectiveness on Pinus radiata (D. Don) against sapstain, mould and decay fungi. Three formulations, sodium pentachlorophenoxide (NaPCP) plus borax, Haipen 50 WP, and Mitrol 375, are used commercially in New Zealand. Busan 1009 (0.5% product), IWD Product A (0.2% ai), IWD Product B (0.3% ai), Fennotox S2 (0.4% product) and Woodguard E.C. (0.5% product) have potential as antisapstain treatments. Kilstain, XP-3359, Celbrite-M81 and Acticide THP were ineffective at the concentrations tested. Formulations containing methylene bisthiocyanate were susceptible to the mould Trichoderma viride.
J A Drysdale


Field performance of novel antisapstain formulations
1997 - IRG/WP 97-30125
The effectiveness as antisapstain formulations of combinations of oxine copper (Cu-8), carbendazim, hexaconazole, cyproconazole, flusilazole, didecyldimethyl ammonium chloride (DDAC), an alkanolamine borate (SB), benzalkonium chloride (BAC), 2-n-octylisothiazolin -3-one (isothiazoline) and p-chlorophenyl-3-iodopropagilformal (CPIPF) was determined for freshly sawn, block-stacked radiata pine in three 18-week field trials: 1. Established in summer 1992 evaluating combinations of hexaconazole, carbendazim and DDAC. 2. Established in autumn/winter 1994 evaluating combinations of hexaconazole, carbendazim, DDAC, BAC and SB. 3. Established in autumn/winter 1995 evaluating combinations of triazoles, DDAC, Cu-8, carbendazim, CPIPF, isothiazoline and SB. Reference standards included: Cu-8; Cu-8 + carbendazim; IPBC + DDAC and TCMTB. In all tests, formulations containing carbendazim + hexaconazole + DDAC gave better protection for 12 and 18 weeks than most other experimental formulations and were equal to or better than commercial standards.
D R Eden, R N Wakeling, C M Chittenden, J G Van der Waals


Design of Field Trials for Evaluation of Antisapstain Products
2003 - IRG/WP 03-20263
Field trialing is an important phase of antisapstain product development and careful planning is required to ensure trial validity for predicting performance in the industrial situation. Experiences of trialing antisapstain products on lumber over a ten-year period are discussed in this paper. It is not mandatory to source "fresh " wood for trialing and useful information can be generated even if the wood shows visible signs of pre-infection. Measurement of uptake of preservative working solution is recommended, as uptakes can differ considerably between preservatives. Also, continuing wood drying after sawing can cause treatment uptakes to progressively increase over the trial duration. Strong moisture gradients develop in treated packets during storage and the moisture profile is a particularly important determinant of the development of the various fungal infections. The period and method of assessment should be appropriate to demonstrate differences between products that would be reflected in sawmill practice.
F W Frazer, N R Edmonds, B J Nairn


Evaluation of a new anti-sapstain formulation
1994 - IRG/WP 94-30035
A new anti-sapstain mixture, which consists of 2% IPBC (3-iodo-2-propynylbutyl carbamate) and 1.5% DCOI (4,5-dichloro-2-n-octylisothiazolin-3-one), was evaluated by three methods in the laboratory. A standardized test (JWPA standard 2) demonstrated that the new anti-sapstain formulation was highly effective in controlling growth of monocultures of five test fungi on wood substrate. When exposed to mixed spore suspension, the formulation performed better than TCP-based commercial product. A larger scale laboratory tests and supplemental trials at sawmills also supported a satisfactory performance of the formulation to protect freshly sawn timber from moulds and sapstain fungi.
K Tsunoda, H Kumagai, M Sakurai


A shower test protocol for measuring antisapstain wash-off from small individual log billets
1996 - IRG/WP 96-50069
According to New Zealand Timber Industry Federation statistics New Zealand exported 4,835,000 m³ of logs in 1994 and it is estimated that c. 20% were anti-sapstain treated. Loss of preservative from logs as a result of rain impact after application is of considerable concern both with respect to potential loss of efficacy and environmental contamination. Whilst Environment Canada have a proposed standard for assessing run off from anti-sapstain treated sawn lumber, the method does not readily allow for the evaluation of anti-sapstain treated logs under relevant time frames, or conditions, for the New Zealand situation. In addition, most of the other available and commercially relevant leaching, or shower tests, were designed to evaluate leaching from vacuum-pressure treated square sawn lumber, or round posts. A test method, loosely based on established methods and developed with the support of industry, is described which quantifies the leaching, or surface run-off of preservatives (ie. anti-sapstain products) from small (£ 45 cm diameter) treated log billets under real time, or accelerated conditions. The method also allows for the influence of several key variables on leaching / surface run-off from anti-sapstain logs to be quantified through manipulation of shower test rig parameters such as: water droplet size & flow rate; log coverage; spray jet shape or angles and shower period (intermittent or single dose).
A J Pendlebury, H Pearson


Laboratory and field trials of novel antisapstain formulations
1997 - IRG/WP 97-30146
This document covers the results of laboratory and field trials of combinations of fungicides formulated using a patented technology (PCT NZ 96/00143). A 3 week laboratory trial that uses radiata pine (Pinus radiata D. Don) branch discs as a substrate was used to determine which combinations possessed a suitable spectrum of fungitoxicity against key sapstain, mould and decay fungi. In particular fungitoxicity against Ophiostoma piceae H & P Syd was looked for as this is the most difficult fungus to control on freshly cut radiata pine in New Zealand. The most promising formulations were then tested using block stacked radiata pine stored for 11 weeks during a high hazard summer period. In general the field trial results corroborated with the laboratory disc trial results. The importance of a broad spectrum of fungitoxicity and in particular a high level of activity against O. piceae, was shown by both types of trial. A formulation containing hexaconazole (0.014%w/v) plus carbendazim (0.028%w/v) plus a quaternary ammonium compound (0.291%w/v) was particularly promising. This formulation achieved significantly better (5% level of probability) control than the commercial standards, for 11 weeks of summer storage. The low fungicide concentrations used auger well for it's cost effectiveness. It is believed that this was in part due to fungicide synergy, broad spectrum activity and the use of microemulsions and solutions of the key fungicide components.
R N Wakeling, P N Maynard, D R Eden, C M Chittenden, B Carpenter


Xylophene AS™, the challenge of developing a modern antisapstain formulation for the french market
2000 - IRG/WP 00-30250
In France Sodium Pentachlorophenol (NaPCP) has been used for more than 40 years for the protection of freshly cut and unseasoned lumber. The French sawmill industry requires a protection of 6 months and maximum 10% surface infection by moulds and/or sapstain fungi. However, this active substance did have some serious environmental flaws and no authorisation was granted for a direct contact of NaPCP treated timber with foodstuffs. During the last fifteen years many new formulations were put on the French market for the temporary protection of maritime and Scots pine. Many products gave varying degrees of protection (from a couple of weeks to maximum 4 months) and the required food-contact allowance was not possible with most of these formulations. For those reasons, DYRUP-XYLOCHIMIE put significant R & D resources into the development of a modern antisapstain formulation that met the efficacy requirements of the French industry, which had a favourable toxicological and environmental profile and could obtain a food-contact allowance without restrictions. A close collaboration with active ingredients suppliers such as JANSSEN PHARMACEUTICA NV and TROY CORPORATION was obtained as well. An internal developed field test was used to study the comparative efficacy of several fungicides (azaconazole, propiconazole, tebuconazole, metconazole, IPBC, carbendazim, isothiazolone and quaternary ammonium compounds) against bluestain and moulds. Based on the field efficacy several combinations of IPBC, propiconazole, carbendazim and isothiazolone were finally retained. Official laboratory tests (NF X 41-547) succeeded by internal field tests revealed a good compromise for a new formulation containing propiconazole, carbendazim and IPBC. This formulation was then officially tested according to the French standards : NF X 41-547 laboratory test and NF X 41-549 field test. Toxicological and ecotoxicity data were also gathered and a complete food contact allowance was obtained by the French Ministry of Economy; Finances and Industry. The formulation was then put on the market as XYLOPHENE AS™ and has now been in practical use for more than three years in several French sawmills with satisfactory results.
E Wozniak, L Cubizolles, N Delourme Fonseca, A R Valcke, J Gors


Surface retentions of PCP, TCMTB and MTC obtained during a field trial of antisapstain formulations
1993 - IRG/WP 93-20002
Formulations containing NaPCP or TCMTB and MTC were included as reference products in a recent field trial of antisapstain formulations in Queensland. Retentions of these actives on the surface of treated sawn Pinus elliottii were monitored by ultrasonic solvent extraction of excised samples and analytical determination by high performance liquid chromatography. Distribution of actives with depth and longitudinal position were monitored for the particular dipping/draining schedule employed, and related to dip concentration and time since dipping. The analytical data provide a direct measure of surface retention in terms of active ingredients per unit area, the assessment method preferred by WG II Sub-group 3 at IRG 23. Even if only applied to these reference treatments, such analysis would facilitate comparison between trials conducted using widely varying treatment regimes and conditions.
D E Ferlazzo, M D Needham, M J Kennedy


Efficacy of Didecyl Dimethyl Ammonium Chloride (DDAC), Disodium Octaborate Tetrahydrate (DOT), and Chlorothalonil (CTL) against Common Mold Fungi
2004 - IRG/WP 04-30338
The fungitoxic properties of four fungicides, alone and in combination, against four different mold fungi commonly associated with indoor air quality problems were evaluated on two different wood species and sheetrock. The fungicides were chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) (CTL) in a 40.4% aqueous dispersion, disodium octaborate tetrahydrate (DOT) in two different forms - a 40% glycol solution and a 98% wettable powder, and didecyl dimethyl ammonium chloride (DDAC) in an 80% solution. The fungi were Aspergillus niger, Cladosporium cladosporioides, Penicillium brevicompactum, and Stachybotrys chartarum. All fungicide treatments on wood reduced growth, sporulation and discoloration of the mold fungi when compared to nontreated specimens. No single fungicide provided total control of all four fungi on wood. CTL provided the best single-agent protection by totally preventing the growth of C. cladosporioides and S. chartarum and reducing growth of A. niger and P. brevicompactum to low levels. DOT in both forms was very effective against A. niger, but provided only sporadic protection against other fungi. DDAC provided good protection against S. chartarum but was not as effective against the other molds. Combinations of the different biocides were more effective than any single agent. DOT + DDAC totally prevented or greatly reduced growth of A. niger, P. brevicompactum and S. chartarum. Cladosporium cladosporioides was the most difficult organism to control, but even this was achieved when DDAC was increased to 1.0% with DOT. The most consistent control of discoloration, sporulation, and growth of the fungi on wood was obtained with the combination of DOT and CTL. DOT, alone or in combination with DDAC or CTL, was also very effective against the fungi on sheetrock. The results suggest that by using appropriate products, during construction or after water damage, problems associated with the growth of common molds and their potential health effects can be avoided.
J A Micales-Glaeser, J D Lloyd, T L Woods


Assessing the leachability of chlorothalonil and methylene bis thiocyanate from antisapstain treated radiata pine
1998 - IRG/WP 98-30176
Rain wash-off and leaching of antisapstain fungicides from wood may cause pollution of waterways and may also lead to a decrease in the efficacy of a formulation against fungal degrade as chemicals deplete from the timber surface. In the current study, the leachability of chlorothalonil (CTL) and methylene bis thiocyanate (MBT), the active ingredients of a commercial antisapstain formulation, was determined. Freshly sawn radiata pine (Pinus radiata D. Don) sapwood boards (500 x 70 x 12mm3) were dip-treated, assembled with and without fillets into packets, and subjected to artificial rain after 1, 3 and 6 days of post-treatment fixation time. Chemical analysis were performed on the leachate from each packet using HPLC. In addition, wood samples were taken from various locations within each packet to determine surface retention levels of CTL and MBT before and after raining. The study showed that minute amounts of CTL leached after artificial raining, but MBT did not leach. Initial wood surface retention analysis demonstrated higher levels of CTL than MBT prior to raining, although in the working solution the active ingredients were present in similar concentrations. This suggests that CTL has a higher affinity for radiata pine than MBT. Resistance of CTL leaching increased with post-treatment fixation time. Regardless of posttreatment fixation time, similar MBT losses were observed from the wood surface after raining and they were about the same order of magnitude as CTL. The lack of MBT in the leachate is perhaps related to the diffusion of MBT into the interior of the wood. Furthermore, breakdown of MBT is probably or likely in the leachate.
B Kreber, T L Woods


Susceptibility of antisapstain fungicides to rain wash-off
1994 - IRG/WP 94-30046
Results of trials using miniature timber packets and simulated rain wash-off are described. Six fungicidal actives in five commercial antisapstain formulations were involved, and a clear influence of rainfall timing after antisapstain treatment was demonstrated. Differences between actives and formulations were most marked where water-spray was applied in the first hour after treatment, though even when applied after a 48 hour delay there were up to ten-fold differences in the percentages mobilised. Possible mechanisms of fixation are discussed in relation to known formulation properties. Results from a full scale trial at a sawmill are also given, and comparison made with the small-scale packet experiments. It is concluded that the results were very similar. The work is extrapolated to the 'real-life' sawmill situation, and conclusions drawn as to the likely results of heavy rain exposure at different times after fungicidal treatment of timber.
R N Wakeling, D J Cross, D R Eden, P N Maynard


Sampling and analysis of NeXgen-treated timber
1998 - IRG/WP 98-20134
Green sawn timber surfaces of the softwood Caribbean pine and the hardwood white cheesewood were treated by dipping, spraying, and precise spiking with the antisapstain product NeXgen. After storing for either two hours or two weeks, the treated surfaces were sampled by one of four alternative protocols, which included two involving a square wad sampling punch (one hit or six hits), one involving an electric planer, and one reference technique where the surface zone was removed and cut on a band-saw. Surface samples were extracted into an azeotropic mixture of acetonitrile and methanol before analysis by high performance liquid chromatography for the active ingredient chlorothalonil. There was little difference in variability between the protocols; coefficients of variation from spiked surfaces varied f rom 3% to 9%. Recovery of spikes varied from 49% to 101%, with efficiency generally better from fresh than dried surfaces, better from softwood than from hardwood surfaces, and better using the single-punch than alternative protocols. Efficiencies of the single-punch protocol were 92% (fresh hardwood), 93% (dried hardwood), 100% (dried softwood) and 101% (fresh softwood). As expected, the inherent variability of surface concentrations produced under dipping and spraying conditions prevented firm conclusions being drawn from these studies, but the single-punch protocol which was superior in the spiking studies generally ranked higher than the alternatives in efficiency on dipped and sprayed surfaces also. The single-punch protocol is recommended for use on both softwood and hardwood surfaces in both freshly-treated and dried condition.
M J Kennedy, D E Ferlazzo, T L Woods, M H Freeman


Detoxification of methylene bisthiocyanate by bacteria isolated from freshly felled, anti-sapstain treated timber
1993 - IRG/WP 93-10017
The microbial defacement of freshly-felled timber treated with organic biocides continues to be a major problem in stored lumber. As part of a study to investigate the depletion in chemical activity of methylene-bis-thiocyanate (MBT) in green timber, bacteria were isolated from freshly-felled boards of Corsican pine (Pinus nigra var. maritima Arnold) previously treated with different biocides. The ability of pure cultures of bacteria to detoxify 100 ppm MBT in liquid culture was tested using High Performance Liquid Chromatography. All of the bacterial cultures tested caused detoxification of MBT. There was a statistically significant relationship between the level of detoxification caused by the bacteria and the final pH of the solutions. At pH values of greater than 5.85, this relationship was linear. At pH values of less than 5.85, results were more variable suggesting that factors other than pH were involved in the detoxification of MBT. The significance of these results is discussed.
R J Wallace, R A Eaton, G R Williams


Time limits for holding logs to achieve successful antisapstain treatment
1997 - IRG/WP 97-30126
The purpose of these trials was to determine the maximum time that logs can be left in winter and summer before treatment if sapstain, caused by pre-treatment infection, was to be prevented. Pre-treatment storage conditions representative of average temperature and humidity for the winter months of June, July and August, and of moderately severe summer conditions, for the Bay of Plenty, New Zealand were employed. After felling and debarking, logs were artificially inoculated with Ophiostoma piceae and Diplodia pini and stored in a well ventilated room at 8°C and 88% RH. At predetermined intervals from the time of felling, including 8 hours (no time in storage room), 24 hours and then at 24 hourly intervals up to 7 days, a sample of log billets was treated with a commercial antisapstain formulation, and stored at ambient temperatures (from July to November or from February to April) in a well ventilated, open-sided barn. Billets were cross-cut into sections 8 and 16 weeks from the time of felling (winter), 8 weeks (summer), and assessed for the presence of internal sapstain. Results showed that for representative winter conditions (8°C and 88%RH) logs could be stored for periods of up to 4 days before treatment without adversely affecting posttreatment sapstain development. However, during reresentative summer conditions (storage at 25°C and 75%RH), storage for more than 8 hours prior to treatment resulted in unacceptable posttreatment sapstain development. Reasons for these differences are discussed.
D R Eden, R N Wakeling, C M Chittenden, J G Van der Waals, B Carpenter


Variable tolerance of Ophiostoma spp. and Diplodia pinea to commercial antisapstain products
1998 - IRG/WP 98-10266
A recent survey of the occurrence of sapstain fungi in New Zealand, conducted at The University of Waikato, provided the opportunity to examine fungicidal tolerance amongst new isolates. It also enabled a comparison of tolerance amongst new isolates with those used in routine antisapstain screening trials at Forest Research. A rapid antisapstain laboratory disc trial was used to determine the extent of fungal growth after three weeks on radiata pine treated with various commercial antisapstain formulations, which was then used as an indicator of susceptibility or tolerance. The results showed that under laboratory conditions, susceptibility to antisapstain formulations varied greatly, both between species, and between isolates of the same species. None of the formulations tested gave good control of all the isolates when tested at commercial usage rates. The significance of these results is discussed in terms of design of laboratory antisapstain trials and relevance in the field.
D R Eden, C M Chittenden, B Kreber, J G Van der Waals, R N Wakeling, R L Farrell, T Harrington


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