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The dry rot fungus and other fungi in houses. Part 1
1992 - IRG/WP 92-2389
J Bech-Andersen


Biological detoxification of wood treated with salt preservatives
1992 - IRG/WP 92-3717
The use of microorganisms that are capable to convert chemically fixed inorganic preservative complexes from impregnated wood waste into watersoluble components is investigated. A number of fungi were isolated from deteriorated and initially well-treated wood. They revealed an exceptionally high production of organic acids (pH 2). The fungi were identified and used together with others of the same genus for experiments under non-sterile conditions on a laboratory scale with CCA-, CCB and CC-treated wood at retention levels of at least 50% higher than recommended for wood in ground contact. As a result Cr and As were leached to more than 90% depending on culture conditions, whereas Cu reacts with oxalic acid to a complex with limited water solubility.
I Stephan, R-D Peek


Silicon tetrachloride: A potential wood preservative
1980 - IRG/WP 3133
In its present form, this paper is a preliminary draft of a paper that will eventually be submitted for publication in the Forest Products Journal. We are continuing the work on the effects of silicon tetrachloride on wood and expect to have additional data for the meeting in May 1980. Specifically we are measuring the penetration rate and depth of SiCl4, and we are chemically analyzing the treated wood with respect of phenolic and other extractives. Our results continue to appear quite favourable for the future use of SiCl4 as a preservative.
C W Owens, W T Shortle, A L Shigo


The influence of fungal species and the level of decay on the mortality and feeding activity of adult Euophryum confine (Broun)
2002 - IRG/WP 02-10448
The mortality and feeding activity of adult Euophryum confine (Broun) (Coleoptera: Curculionidae) are used to establish the substrate conditions most suitable for their rearing. Weevils were allowed to feed on Pinus nigra (Arnold) sapwood blocks, either undecayed or decayed to 10% weight loss ±5% by two brown rots Coniophora puteana (Schum.:Fr.) Karst. and Serpula lacrymans (Wulf.:Fr.) Schroeter, or the white rot Fibroporia vaillantii (DC.:Fr.) Parmasto in a non-choice test for seven days at 20°C (±1°C) and 92% relative humidity ±5%. Weevils were also allowed to feed on blocks acid pre-treated to 10% (±1%) weight loss. Weevil mortality and block weight losses resulting from feeding were recorded. Those pre-treatments resulting in low mortality and high feeding activity were considered most suitable for rearing adult weevils.
M Green, A J Pitman


The effects of copper proximity on oxalate production in Fibroporia radiculosa
2014 - IRG/WP 14-10823
Copper remains a key component used in wood preservatives available today. However, the observed tolerance of several critical wood rotting organisms continues to be problematic. Tolerance to copper has been linked to the production and accumulation of oxalate, which precipitates copper into insoluble copper-oxalate crystals, thus inactivating copper ions. The purpose of this study was to assess differences in oxalate production and decay capacity of four wood decay fungi (three copper-tolerant and one copper-sensitive) exposed to various applications of copper. Three Fibroporia radiculosa isolates and one Gloeophyllum trabeum isolate were subjected to one formulation of copper citrate presented to the test fungi by four different treatments in Southern pine wood blocks for an eight week period. Samples were evaluated for oxalate production and weight loss every two weeks. Two of the copper-tolerant isolates evaded the inhibitory effects of all four copper treatments by week eight. The copper-sensitive organism exhibited some limitations to actively decay blocks in two of the four copper treatments. These findings suggest that proximity to copper citrate, available in any form (i.e. impregnation, direct contact, free liquid or close proximity) generally, had no negative effect on fungal growth, oxalate production, and decay capacity of the copper-tolerant organisms. Results also suggested that the copper-sensitive fungus was restricted in its ability to effectively decay wood when copper was pressure treated or directly added to the surface of wood blocks. This study also suggested that close proximity to copper alone (i.e. not pressure treated) did not completely inhibit decay of the copper-tolerant or copper-sensitive test fungi.
K M Jenkins, C A Clausen, F Green III


Selection of Wood-Rotting Basidiomycetes for Inoculation of an Accelerated Soil Bed Test
2014 - IRG/WP 14-20543
There is a need for a test method that guarantees exposure of treated wood to soil and preservative-tolerant wood-rotting basidiomycetes as standard field tests do not do this reliably. The ability of a range of selected wood-rotting basidiomycetes to grow through unsterile forest soil was investigated in a Mason jar test assembly. None of the white-rot fungi in test grew through this soil. Four of the brown-rot fungi grew through the soil, and decayed water-treated control mini-stakes to the point of failure during 12 weeks of incubation. Based on the results of this study, consideration of prevalence in North America, preservative tolerance, and pattern of growth, one isolate each of two brown-rot fungi was selected to be used in future accelerated soil bed test experiments to ensure the presence of wood-rotting basidiomycetes in the soil . These were L. pinastri Findlay 141 and F. radiculosa L-7878-Sp. In addition, this unsterile soil-jar test method should be developed into a laboratory screening test for ground contact wood preservatives where biodegradation and basidiomycete exposure are assured.
P I Morris, A Uzunovic, J Ingram


The copper-transporting ATPase pump and its potential role in copper-tolerance
2016 - IRG/WP 16-10859
Copper-tolerant brown-rot decay fungi exploit intricate mechanisms to neutralize the efficacy of copper-containing preservative formulations. The production and accumulation of oxalate is the most widely recognized theory regarding the mechanism of copper-tolerance in these fungi. The role of oxalate, however, may be only one part of a series of necessary components required for this complex mechanism. Annotation of the Fibroporia radiculosa genes involved in copper-tolerance characterized a subset of proteins, three copper-transporting ATPase pumps, which regulate copper concentrations inside the fungal cell by exporting excess copper ions. The goal of this study was to determine the relevance of copper-transporting ATPase pumps in the mechanism of F. radiculosa copper-tolerance. Southern pine test blocks were pressure-treated with 0.6%, 1.2%, and 2.4% ammoniacal copper citrate and subjected to a copper-tolerant strain of F. radiculosa and a copper-sensitive strain of Gloeophyllum trabeum in decay tests over a four week period. Untreated Southern pine test blocks subjected to both test fungi served as controls. Expression levels of three copper-transporting ATPase pumps were evaluated each week by qRT-PCR. F. radiculosa showed up-regulation of all three ATPase pumps when exposed to the copper treatments over the course of this study. G. trabeum showed down-regulation of ATPase1 and ATPase2 and no expression of ATPase3 when exposed to the copper treatments over the course of this study. Up-regulation of the three ATPase pumps can be correlated to the ability of F. radiculosa to decay copper-treated wood (12% weight loss at week 4). Down-regulation of ATPase1 and ATPase2 and lack of ATPase3 expression can be correlated to the inability of G. trabeum to decay copper-treated wood (1% weight loss at week 4). Preliminary results indicate these three ATPase pumps function as an essential component of the complex mechanism of copper-tolerance utilized by F. radiculosa.
K M Ohno, C A Clausen, F Green III, G Stanosz