Your search resulted in 47 documents. Displaying 25 entries per page.
Antifungal properties of metabolites produced by Trichoderma isolates from sawdust media of edible fungi against wood decay fungi
1994 - IRG/WP 94-10051
Trichoderma isolated from a sawdust medium of Pholiota nameko produced filtrates which had antifungal activities to four wood decay fungi tested on the agar plates. Filtrates produced from another isolate, from a sawdust medium of Lentinus edodes, had antifungal activities only to the white rot fungi, Coriolus versicolor and Pycnoporus coccineus. These results did not agree with those from earlier decay tests using wood blocks pretreated with the isolates. The difference of antagonistic potential was possibly due to the different condition of incubation procedure.
S Doi, M Mori
Biological control with Trichoderma harzianum in relation to the formation for spores the production of soluble metabolites
1994 - IRG/WP 94-10073
The amount of spores produced by three strains of Trichoderma harzianum on the aerial mycelium of agar cultures and in shake cultures, respectively, correlated with the inhibition zones exerted against Phanerochaete chrysosporium in an agar diffusion test. The amount of soluble antifungal metabolites as well as the protein content also correlated with the inhibition zones and the amount of spores produced. The antifungal metabolites were identified to be trichorzianines. They were the only compounds with antifungal activity. It is concluded that the trichorzianines are responsible for the biocontrol effect by soluble metabolites and that they are produced during conidiogenesis.
J Bürgel, E Horvath, J Haschka, K Messner
Conservation of wooden cultural property
1994 - IRG/WP 94-30038
A survey of the conservation of wooden archtitectual monuments, art objects and archaeological finds is presented. Each of the three areas has typical conservation problems which reqire the use of selected wood preservatives and consolidation agents. Furthermore specific protection and consolidation methods are necessary. A precise damage diagnosis with non-destructive testing methods is the first step in a careful conservation work.
A Unger, W Unger
Antifungal mechanism of dichloro-N-octylisothiazolone
1998 - IRG/WP 98-30183
4,5-dichloro-N-octylisothiazolin-3-one (DCOI) is a member of the isothiazolone class of preservatives, whose antimicrobial mechanism of action has been intensively studied over the last decade. DCOI has also been intensively studied for use in wood preservation. The isothiazolones are electrophilic molecules that rapidly react with thiol groups to form covalently bonded isothiazolone-thiol adducts. This ability to bond with thiol groups is crucial to their ability to act as preservatives. Thiol groups are present in proteins as part of the amino acid cysteine, where they play an important role in maintaining protein structure and function. A number of enzymes have thiol groups at the site where the enzyme function is performed, and these thiol groups may participate in the enzyme reaction. If the isothiazolone reacts with this thiol group, the activity of the enzyme is inhibited. Our studies have shown that there are several enzymes in the Krebs cycle that are inhibited by isothiazolones and these enzymes are required to generate energy and perform many biosynthetic functions. Reflective of this, DCOI has been shown to be a rapid inhibitor of cellular respiration, causing the cell to cease consuming oxygen almost immediately upon contact with DCOI. The multiplicity of targets and their central importance to the metabolism of the cell, as well as the fact that all microbes use at least parts of the Krebs cycle, can be related to the low use levels and broad spectrum of activity of DCOI. The antimicrobial mechanism of DCOI results in a potent rapid-acting preservative with a broad spectrum of antifungal and antibacterial activity that is effective at low levels.
J S Chapman, M A Diehl, K B Fearnside, L E Leightley
Antifungal activity of a stilbene glucoside from the bark of Picea glehnii
2001 - IRG/WP 01-10402
Stilbene glucosides are widely distributed as phenolic extractives in the bark of Picea glehnii, a commercially species planted in the northern area of Japan, and its content reaches to more than 10% by the dried weight of the bark. Although antifungal activities of these compounds have been reported, the mechanism of growth inhibition is still unclear. Isorhapontin (5,4'-dihydroxy-3'-methoxystilbene-3-ß-D-glucoside) is the major constituent of the stilbene glucosides in the bark of P. glehnii. In the present work, the relation between metabolism and antifungal activities of isorhapontin for the white-rot fungus Phanerochaete chrysosporium and the wood staining fungus Trichoderma viride was investigated. Inhibition of fungal growth was obviously depending on the conversion of isorhapontin to the aglycone isorhapontigenin (3'-methoxy-3,5,4'-trihydroxystilbene) by ß-glucosidic activities in the cultures. Exogenous addition of ß-glucosidase also enhances the antifungal activity of isorhapontin. Moreover, less than 100 ppm addition of the stilbene aglycone isorhapontigenin is sufficient to inhibit the growth of both fungi. However, further metabolism of isorhapontigenin was observed after prolonged incubation of the fungi and resulted in detoxification.
S Shibutani, M Samejima
Antifungal properties of new quaternary ammonium and imidazolium salts against wood decay, staining and mould fungi
2004 - IRG/WP 04-30347
The biological activity of twenty-four potential wood preservatives – imidazolium and quaternary ammonium salts with a modified anion structure was determined employing screening agar-plate and agar-block methods. Experiments were carried out on Scots pine (Pinus sylvestris L.) wood. The aim of the performed studies was to investigate the effect of structure modification of IC and QAC with organic anions or copper (ll) and zinc complexes on their biological activity against wood decay, staining and mould fungi. The fungicidal value of new compounds for Coniophora puteana ranged from 0.64 kg/m3 to 2.2 kg/m3. Aspergillus niger turned out to be the most resistant fungus to the action of modified IC and QACs, whereas Sclerophoma pityophila was effectively inhibited by the examined salts. The performed soil-block tests showed that the IC and QAC were leached from the experimental wood in conditions of contact with moist soil and revealed their fungal detoxification by mould fungi, especially by Gliocladium roseum. Observations made using the scanning electron microscope of the colonization and decay of treated wood by mould fungi confirmed tolerance of mould fungi to QACs.
J Zabielska-Matejuk, W Wieczorek
On the effectiveness of fumigants against wood-destroying insects and fungi in wooden cultural property
1993 - IRG/WP 93-10030
Based on a survey of the history of the use of fumigants the actual agents are mentioned in relation to their biogenic effect on wood-destroying insects and fungi as well as their corrosive behavior on cultural property. Furthermore the conditions for the use of reactive fumigants in buildings are discussed. Trials to control wood-destroying insects and fungi by nitrogen and bromomethane are the main aspect. The extermination of larvae of wood-infesting insects depends on the time of diffusion of nitrogen through wood. The mycelium of the tested Basidiomycetes is eradicated by a dose of 25 mg/l bromomethane, but the dose for the tested Ascomycetes has to be more than 50 mg/l bromomethane.
W Unger, A Unger
The antifungal efficacy of Guayule resin
1987 - IRG/WP 3429
The Naval Research Laboratory is evaluating the non-rubber-producing portion of guayule (Parthenium argentatum) resin as a protectant for wood in terrestrial and marine service. This study phase, in collaboration with the universities of Arizona and Mississippi State, evaluates the resin's fungicidal worth. Resin-impregnated pine sapwood was exposed to brown rot fungi (Gloeophyllum trabeum, Antrodia carbonica, Formitopsis cajanderi, Lentinus ponderosa), white rot fungi (Dichomitus squalens, Trametes versicolor, Ganoderma sp.), and a natural inoculum of soft rot fungi from unsterile soil. The exposures for the brown and white rot fungi lasted 20 weeks, using malt agar chambers inoculated 2 weeks prior to the introduction of the treated wood; the soft rot exposure lasted 12 weeks and included treated birch specimens. Weight loss data showed a definite inhibition of decay of the treated wood by the brown and white rot fungi, however there was some decay caused by Lentinus ponderosa (closely related to creosote-tolerant Lentinus lepideus) and by Antrodia carbonica, a common utility pole fungus. None of the resin-impregnated pine or birch specimens were attacked by the soft rot fungi, even those specimens containing the lowest of the three resin concentrations in the wood. In both sets of exposures all of the controls were decayed.
J D Bultman, R L Gilbertson, T L Amburgey, J E Adaskaveg, S V Parikh, C A Bailey
Effect of boron compounds-furfuryl alcohol treatment of wood on dimensional stability, termite resistance and boron leachability
2001 - IRG/WP 01-40195
Sapwood blocks of Japanese cedar (Cryptomeria japonica) and Caribbean pitch pine (Pinus caribaea) measuring 20 (tangential) x 20 (radial) x 10 (longitudinal) mm were impregnated with furfuryl alcohol (FFA) by a vacuum-diffusion process followed by curing under heating. Boron compounds (boric acid, ammonium borate and ammonium biborate) were mixed in the impregnation solution of FFA. Anti- swelling efficiency, water holding capacity and moisture exclusion efficiency were measured. Boron leachability was determined by ion chromatography with ten leaching cycles according to JIS 9201 (1992). The specimens were exposed to termite attack testing, before and after the cyclic leaching process. The results indicated that FFA imparted to wood greater dimensional stability when mixed with boron compounds. Boron when mixed with FFA behaved differently to boron alone treatment, although it was still leachable. The wood specimens treated with FFA-boron compounds were quite resistant to termites even after severe leaching.
S K Ozaki, M K Yalinkilic, Y Imamura, M F Souza
Preservative treatment of common timbers and bamboos of Bangladesh for rural electrification infrastructure
1998 - IRG/WP 98-40104
Researches revealed new treatment grades, treatment groups, grading groups, natural durability grades, strength groups and a new preservative combination for remedial treatment and sterilization of most common timbers and bamboos of Bangladesh. The obtained findings are applicable for equivalent timber species having equivalent climatic condition. Sapwoods are always perishable and timbers with whitish to grayish heartwood without tylosis are found to be nondurable and permeable to preservative treatment, recommended to use after preservative treatment following appropriate treatment group. Perishable to durable impermeable heartwoods can be penetrated with boron, suitable for indoor use only. CCA-C is suitable and preferable preservative for ground and water contact use rather than CCB and pentachlorophenol as the laters are leachable. Decay pattern study revealed that the service life of round timber for ground contact use is increased with the increase of adequately CCA-C impregnated (w/w 4% or 20 kg/m3 dry oxides of CCA-C) shell thickness, the preferable shell thickness shall be at least equivalent to 44% of radius (carry 90% of bending load) where remaining untreated central core is not naturally very durable. Kiln-drying with heat sterilization schedule is a key step for adequate treatment and slow drying or accelerated fixation is the post treatment effective step for higher service life.
A K Lahiry
Biocidal property of the phenolic fraction of ethanol extractives of Hopea parviflora heartwood
1993 - IRG/WP 93-30003
Natural resistance of some species of timber to fungal decay and insect damage (particularly termite) is ascribed toxic nature and quantity of certain chemical substances present in the cell wall of heartwood. These chemical substances generally known to be Phenolic and Polyphenolic compounds (Rao 1982). Earlier investigations on extractives were mainly in relation to resistance of timber to decay and studies that induce resistance to termite attack had not received enough attention. Treated wood with phenolic fraction of ethanol extractives of Hopea parviflora heartwood have shown inuced resistance against decay fungi and termites, indicating these chemical substances are having biocidal properties. The observation warrant detailed chemical studies of the extractives for their utilisation of wood protective substance.
R V Krishnan, K S Theagarajan, H S Ananthapadmanabha, M Nagaraja Sharma, V V Prabhu, H C Nagaveni
Antifungal activity in metabolites from Streptomyces rimosus
1991 - IRG/WP 1495
The objective of this study was to evaluate the efficacy of antifungal metabolites from Streptomyces rimosus for controlling the growth of sapwood-inhabiting fungi: sapstain fungi - Ceratocystis coerulescens, Ceratocystis minor, Ceratocystis pilifera, and Aureobasidum pullulans; mold fungi - Aspergillus niger, Penicillium spp, and Trichoderma spp. Production of antifungal metabolites by Streptomyces rimosus was studied using petri plate assay, plate bio-assay, wood-block tests, and green pine log sections. The metabolites inhibited mycelial growth at a distance in petri plate assay; clear zones were exhibited around the wells in plate bio-assay. Treatment of Southern Pine and sweetgum blocks and green pine log sections with concentrated metabolites inhibited conidial germination and prevented discoloration.
S C Croan, T L Highley
In vitro antifungal activity of chilli against wood degrading fungi
2006 - IRG/WP 06-10572
The efficacy of chilli juice and/or chilli extract oleoresin as antisapstain agents was evaluated against two common sapstain fungi, Sphaeropsis sapinea and Leptographium procerum. Possible synergy between chilli juice and Lactobacillus casei as antisapstain agents was also assessed. Both the chilli juice and the oleoresin showed moderate antifungal activity. No growth of the test fungi was observed on plates amended with 50% chilli juice after 3 weeks of incubation. In the presence of 0.1% oleoresins, fungal biomass was reduced by more than half when compared with unamended controls. The synergy between chilli and Lactobacillus casei was apparent; the combination of chilli/L. casei treatment system afforded much better inhibition than chilli or L. casei alone. In the presence of 25% chilli juice with L. casei the growth of test fungi was stopped.
T Singh, C Chittenden, D Vesentini
Antifungal activity of plant derived extracts against G. trabeum
2007 - IRG/WP 07-30433
While synthetic chemicals have provided excellent protection to woods used in adverse environments, the general public remains interested in naturally derived wood protectants. There are diverse arrays of possible candidates, but many of these compounds are not readily water soluble and efforts to render them soluble often reduce biological activity. In this report, we describe efforts to enhance water solubility of various plant extracts, while retaining activity against Gloeophyllum trabeum, a common wood decay fungus. The results suggest that polyvinylpyrrolidones have potential as co-solvents for many plant extracts.
M Maoz, I Weitz, M Blumenfeld, C Freitag, J J Morrell
Detection of Anti-Fungal Sapwood Extractives in Non-Durable Scots Pine (Pinus sylvestris), Rubberwood (Hevea brasiliensis) and Jelutong (Dyera costulata)
2007 - IRG/WP 07-10634
A general laboratory bioassay method of Woodward and Pearce (1985) was adopted to detect anti-fungal activity of sapwood or heartwood extractives of 5 Malaysian hardwoods [dark red meranti heartwood (Shorea spp.), red balau heartwood (Shorea spp.), kulim heartwood (Scorodocarpus borneensis), jelutong sapwood (Dyera costulata) and rubberwood sapwood (Hevea brasiliensis), including the temperate Pinus sylvestris (Scots pine sapwood). The heartwoods of these species and Scots pine sapwood are known to be highly resistant to decay by soft-rotting Ascomycetes and anamorphic fungi (about 1-7% wood mass loss), while the sapwoods of rubberwood and jelutong had much reduced soft rot resistance (respectively 35, 32% wood mass loss) but obviously prone to sapstain and mold attack, including that of Scots pine. Crude methanol extracts of woodmeal samples of each wood species were loaded on to thin-layer chromatography plates at between 0.003 and 0.1 g fresh mass equivalent of woodmeal per spot so as to optimize resolution of separated compounds, and developed with chloroform:methanol solvent (ratio 19:1). The dried plates were sprayed with fresh fungal spores of Cladosporium cucumerinum and incubated at >90% RH for 5 days in the dark. Presence of anti-fungal compounds was revealed by white regions along the solvent transect for each extract of each species where inhibited spore germination and mycelial growth of C. cucumerinum occurred. Comparisons of anti-fungal activity of extracts between species and between sapwood and heartwood were made. Results revealed that several zones of inhibitory activity, indicated by their Rf-values, were clearly visible on chromatographic separations of methanol extracts of these 5 wood species. The inhibitory zones for 2 heartwood extracts (except kulim) did not move from the origin which was also resistant to infection. However inhibition zones were also detected for the sapwoods of rubberwood, jelutong and Scots pine against C. cucumerinum despite the known sapstain and decay susceptibility of these wood substrates. The presence of hitherto unidentified anti-fungal compounds in the sapwoods of these species may elicit limited potency or narrow spectrum protection from fungal infection and onset of stain or decay.
A H H Wong, R B Pearce
Antifungal activity and synergistic effect of cinnamaldehyde combined with antioxidants against wood decay fungi
2007 - IRG/WP 07-30445
The objective of this study was to investigate the antifungal activity and synergistic effect of cinnamaldehyde combined with antioxidants against wood decay fungi. Five antioxidants, propyl gallate, octyl gallate, quercetin, eugenol and catechin were tested against various wood decay fungi. Octyl gallate and eugenol were found to be the only two antioxidants processed antifungal activities. IC50 values of octyl gallate were 0.47 and 0.04 mM against L. betulina and L. sulphureus, respectively. The IC50 values of eugenol were 0.37 and 0.25 mM against L. betulina and L. sulphureus, respectively. The synergistic effects were also found on the combinations of octyl gallate-cinnamaldehyde and eugenol-cinnamaldehyde. The combination of either using octyl gallate with cinnamaldehyde or eugenol with cinnamaldehyde greatly reduced the concentrations to achieve the inhibitory effect that a higher concentration was needed by octyl gallate, eugenol or cinnamaldehyde alone. The antifungal action of octyl gallate could be attributed to its pyrogallol group functioning as an attached moiety to the hydrophilic portion of the membrane surface and the octyl moiety interfering with the hydrophobic interior surfaces of the membrane. Meanwhile, the synergism of cinnamaldehyde with octyl gallate or eugenol could be due to the interference of fungal cell wall synthesis and destruction on cell wall and membrane plus the additional radical scavenging effect. Results also suggested that antioxidant with fungicidal effect might be a better candidate than pure antioxidant for the system of fungicide/antioxidant.
Fu-Lan Hsu, Tsair-Bor Yen, Hui- Ting Chang, Shang-Tzen Chang
Effect of cinnamon oil and clove oil against major fungi identified from surface of rubberwood (Hevea brasiliensis)
2007 - IRG/WP 07-30446
Antifungal activities of cinnamon oil and clove oil at ratio 1:1 and pure against major fungi found on surface of rubberwood (Aspergillus niger, Penicillium chrysogenum, and Penicillium sp.) were investigated using the broth dilution method. The minimum inhibitory concentration (MIC) of the combined cinnamon and clove oils for these test moulds was determined to be 80 µL/mL which were less than or equal to the MIC of the pure oils. Antifungal activity of the combined cinnamon and clove oils at the MIC was further examined on rubberwood. It was found that all moulds on rubberwood were completely inhibited for at least 12 weeks under the storage condition at 30°C and 100%RH.
Narumol Matan, Nirundorn Matan
A hypothesis on a second non-biocidal property of wood extractives, in addition to toxicity, that affects termite behavior and mortality
2008 - IRG/WP 08-10638
While it is has long been recognized that heartwood extractives affect termite behavior, the exact cause and relationship between total extractives, extractive types, and termite resistance remains unclear. Generally, researchers have proposed that the extractives are toxic and/or repel termites. We propose, based on the well known fact that many extractives have excellent antioxidant properties in addition to some termite toxicity, that: 1) the antioxidant properties of wood extractives interfere with the termite and symbiotic microbial digestion of lignocellulose; 2) thus, over time termites have learned to recognize and avoid wood with high levels of antioxidants; and 3) consequently, termites will also avoid wood treated with artificial and nontoxic antioxidants. Use of an artificial and nontoxic antioxidant will allow one to definitively test our hypothesis, while tests with natural extractives would be confounded by natural extractives often having both toxicity and antioxidant properties. We conducted some initial tests employing a man-made and benign antioxidant, BHT. In outdoor field trials, ground-contact stakes treated with only the antioxidant had less termite degradation than the control stakes at up to three years of exposure. An initial termite choice experiment using Reticulitermes flavipes Kollar (Eastern subterranean termite) was run with an untreated and 1- or 3%-BHT treated wafer in each jar, along with control jars that contained two untreated wafers. No termite feeding occurred on any of the BHT-treated wafers, indicting that the non-biocidal antioxidant was a strong feeding repellent. Furthermore, while only about 2% termite mortality occurred in the jars that contained two untreated wafers, in every jar that had an untreated wafer and a second BHT-treated wafer 100% mortality occurred. Recent no-choice laboratory tests with two subterranean termite species, R. flavipes and Coptotermes formosanus Shiraki (Formosan subterranean termite), and an exterior test with BHT-treated wood with Formosan termites, confirmed our initial results.
T P Schultz, K Ragon, D D Nicholas
Antifungal activity of different molecular weights of a biopolymer chitosan against wood decay fungi
2008 - IRG/WP 08-30456
In recent years chitosan has been investigated as a natural polymer for wood preservation against fungal decay. From an environmental point of view, chitosan seems to possess a potential approaches as wood protecting agent. In this study, three different molecular weights of chitosan compounds (with approximately the same degree of deacetylation 83 ± 2 %) were evaluated as in vitro and in vivo assessments against two wood decay fungi (Coriolus versicolor and Poria placenta). Average molecular weights of chitosan samples were determined by measurements of intrinsic viscosity and were found to be 3.60×105 Dalton for low molecular weight (LMW), 6.11×105 Dalton for medium molecular weight (MMW) and 9.53×105 Dalton for high molecular weight (HMW). In vitro antifungal assay was carried out using of a mycelial radial growth inhibition technique. The results showed that the antifungal activity was increased with a decreasing of the molecular weight and a LMW chitosan was exhibited a high antifungal potency against Coriolus versicolor and Poria placenta with EC50 of 1876 and 1744 mg.L-1, respectively. In addition, the results revealed that Poria placenta was more sensitive to these compounds than Coriolus versicolor. Preliminary in vivo biological test was carried out on malt agar using a miniblock technique for beech and Scots pine sapwood with Coriolus versicolor and Poria placenta, respectively. After six weeks of exposure to fungal attack all chitosan protective systems tested proved their relative effectiveness when compared to the control specimens. Furthermore, chitosan LMW was the most effective compound among all treatments at the higher concentration against the tested fungi.
A S O Mohareb, M E I Badawy
Investigation into the antifungal properties of herbal remedies for potential use in the wood preservation industry
2008 - IRG/WP 08-30462
The efficacy of herbal remedies as potential antifungal agents was evaluated against two sapstain and three decay fungi. Sapstain fungi included Sphaeropsis sapinea, and Leptographium procerum, and decay fungi were Oligoporus placenta, Coniophora puteana, and Schizophyllum commune. Out of six herbal remedies tested, three showed moderate to high antifungal activity. Caprylic acid had high antifungal activity (MIC of 0.005 – 0.025% w/v dependant on fungi) when tested on Petri-dishes and moderate activity when progressed to pure culture wood decay trials. Pau d’arco and echinacea both showed moderate antifungal activity in vitro. There appeared to be an enhanced antifungal activity when caprylic acid with pau d’arco or caprylic acid with echinacea was evaluated. However when all three extracts were tested in combination, activity decreased.
Antifungal activity of essential oils against common wood degrading/decaying fungi
2008 - IRG/WP 08-30465
Despite the wide use of essential oils in pharmaceutical and food industry as antimicrobial agents, their use as wood preservatives has not been fully explored. In this study, 12 essential oils were screened in nutrient medium for their antifungal activity against 8 common mould, sapstain or decay fungi. Subsequently, one essential oil, eugenol was evaluated for decay resistance in an agar/wood block tests using both unleached and leached cycles with radiata pine sapwood blocks. During the initial in-vitro screening trial, variability in the tolerance of the tested fungi towards the selected essential oil was apparent. Some of the essential oils such as geranium, cinnamon leaf and eugenol completely inhibited the growth of all test fungi at 0.5% w/v on nutrient medium, whereas, three essential oils; eucalyptus, olive leaf and kolorex® were unable to restrict the growth of any test fungi even at 1% w/v concentration. Durability test results on radiata pine confirmed the antifungal activity of eugenol but highlighted the leachibility of this compound from wood. Blocks treated with 3% w/v eugenol without a leaching cycle had less than 1% weight loss when exposed to all three tested wood decaying fungi, Oligoporus placenta, Coniophora puteana and Antrodia Xantha. However, blocks which were leached showed weight losses in the range of 13.40 to 23.12%. This study identified eugenol as a potential benign wood preservative for treatment of timber not exposed to severe leaching, e.g. New Zealand Hazard Class H1.2. However, to be used for higher decay hazard situations, further work for in-situ polymerization of eugenol to fix active(s) in wood will be required.
T Singh, C Chittenden
The Comparison of Fixation and Leachability of Bark, Fruit and Leaf Tannin Extracts with Boron Minerals
2008 - IRG/WP 08-30473
Tannins extracted from several plants have natural durability properties. Due to these properties, some of the researchers have studied them for protecting wood. In this study, Scots pine (Pinus sylvestris) and beech (Fagus orientalis) wood samples were treated with bark, fruit, and leaf extracts as well as water-based wood preservative salts at various concentrations to increase fixation. The penetration, fixation, and antifungal properties of different treatment solutions were compared. Retention levels were generally higher for Scots pine wood than beech wood. The highest retention levels were seen in wood treated with valex and sumex, which are extracts of oak fruits and sumac leaves, respectively. Leaching tests indicated that both wood types treated with sumac extracts showed higher retention levels than wood treated with the other fruit and bark extract solutions. Adding 1% water-based wood preservative salts to valex and sumac extracts increased the retention levels. Higher concentrations of wood-preserving salts accelerated and increased the amount of leaching. We found that the extract alone was resistant to leaching. Mycological tests showed that bark extract solution was the most effective at preventing mycelium penetration and that adding water-based wood-preservative salts to all extract solutions significantly affected the resistance of the wood against fungal infection.
S Sen, C Tascioglu, K Tirak
Antinomic natural self-protection mechanism in long-lasting woods: a case study with three tropical species from French Guiana
2009 - IRG/WP 09-10696
We demonstrate in this work through 3 examples that Amazonian trees may specialize long-lasting woods by means of at least to different approaches. Wallaba impregnates its wood with large amounts of weakly antifungal compounds acting in synergy, while tatajuba and louro vermelho woods are naturally impregnated with antifungal agents. Comparison of biological activities in vitro and concentrations in the woods indicate that these compounds alone may account for the natural durability of the two woods.
A Rodrigues, M Royer, N Amusant, J Beauchêne, G Herbette, V Eparvier, A Thibaut, L Salmen Espíndola, B Thibaut, D Stien
Antifungal Activities of Three Supercritical Fluid Extracted Cedar Oils
2009 - IRG/WP 09-30501
The antifungal activities of three supercritical CO2 (SCC) extracted cedar oils, Port-Orford-cedar (POC) (Chamaecyparis lawsoniana), Alaska yellow cedar (AYC) (Chamaecyparis nootkatensis), and Eastern red cedar (ERC) (Juniperus virginiana L), were evaluated against two common wood decay fungi, brown-rot fungi (Gloeophyllum trabeum) and white-rot fungi (Trametes versicolor). The statistical analysis showed that SCC extracted cedar oils had higher antifungal activities othan hexane Soxhlet extracted cedar oils against both white-rot fungi and brown-rot fungi. In vitro studies showed that AYC oils showed the strongest antifungal activity among the three cedar wood oils, followed by POC oil and ERC oil.
Tianchuan Du, T F Shupe, Chung Y Hse
Potential of antifungal and antitermitic activity of several essential oils
2009 - IRG/WP 09-30515
In the recent years, there has been an increasing concern regarding the safety of wood preservatives. Many research groups have examined the potential of essential oils as biocide based on their biological activity. This paper described the antitermitic and antifungal activity of twenty four essential oils from different plant species. The termicidal activity was carried out with a no-choice test with impregnated filter papers at several concentrations. Screening tests with mycelium of basidiomycete with different concentrations of essential oils were used to assess the fungicidal activity. The essential oils were less active against termites than fungi. Essential oil from savory was the most active and the threshold is under 1% while six essential oils were active against white and brown rot with a threshold under 0.1% (v/v). These results suggest essential oils may be active ingredients of interest for the development of wood preservatives.
N Amusant, M-F Thévenon, N Leménager, E Wozniak