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Basidiospore germination threshold against borate in-vitro may vary between liquid and agar media
1992 - IRG/WP 92-2405
The concentration of disodium octaborate (BAE) which prevented mycelial growth of a common brown rot and 3 white rot fungi was compared to that required to prevent basidiospore germination on malt extract agar. Spore germination sensitivity was lower (50%) for only one of the white rot fungi. However, when spore germination thresholds were tested in malt extract-borate solutions in well slides (no agar), much lower thresholds were noted for 3 of 4 fungi. Neither set of threshold data predicted that noted in limited tests on aspen (Populus tremuloides).
E L Schmidt, Ya-Lih Lin

Synergistic effect of boron on Streptomyces rimosus metabolites in preventing conidial germination of sapstain and mold fungi
1992 - IRG/WP 92-1565
We evaluated the synergistic effect of boron (4% BAE solution of Tim-Bor or 4% boric acid) on Streptomyces rimosus metabolites in preventing spore germination of sapstain and mold fungi using plate bioassay, Southern yellow pine and sweetgum block tests, and green pine log sections: sapstain -- Ceratocystis coerulescens, Ceratocystis minor, and Aureobasidum pullulans; mold fungi -- Aspergillus niger, Penicillium spp, and Trichoderma spp. Inhibition of spore germination in plate bioassay by metabolites with boron was more effective than without added boron. Treatment of wood samples with the mixture of boron and unconcentrated metabolites also resulted in the synergistic effect and completely inhibited spore germination of sapstain and mold fungi.
S C Croan, T L Highley

Monographic cards for wood-destroying fungi. [Fiches monographiques pour les champignons lignivores]
1970 - IRG/WP I 5B
C Jacquiot

Successive collections of Basidiospores from wood decay fungi (in vitro) show variation in germination levels on common media
1978 - IRG/WP 191
In the course of various preliminary experiments in which spore germination levels of 6 decay fungi on malt and water agar were recorded as controls, it was noted that one could not reliably obtain an expected level of spore germination for any particular fungus. Inconsistent 'control' spore germination levels of a fungus greatly complicates large scale experiments in which comparisons of data based on germination levels are attempted upon replication of the study over time. This study was done to determine if, in fact, spores collected at different times from specific hymenial areas of wood decay fungi sporulating in vitro differed significantly in germination level on common media under standardized conditions.
E L Schmidt, D W French

Use of vermiculite as substrate in assays on phytotoxicity of treated wood
1989 - IRG/WP 3547
It is considered the possibility of using vermiculite instead of soil as substrate in assays on phytotoxicity of wood treated with preservatives for agricultural use. Three organic preservatives were used. It had been tested the behaviour of both, vermiculite and soil in case of preservative leaking due to a leach. So that, assays of germination with cucurbitaceous were carried out, mixing a dose of preservatives with both substrates.
M V Baonza Merino, D Franco

Influence of aliphatic acids on spore germination of wood decay fungi
1984 - IRG/WP 2224
Influences of eight saturated fatty acids (C5-C10, C12 and C16) on spores of four isolates of wood decaying basidiomycetes (white rot fungi: Poria tenuis and Trametes hispida; brown rot fungus: Gloeophyllum trabeum [two isolates]) were observed in-vitro. Spore response after 24 hr on malt extract agar containing 10, 10² , or 10³ ppm of each fatty acid included: no effect on normal germination, delayed germination or restricted mycelial growth, vacuolation and degeneration of spore cytoplasm, or germination inhibition without loss of spore integrity. C7-C10 acids destroyed spores of all fungi at 10² ppm whereas spores remained 'intact' at 10³ ppm of the same acids. C12 destroyed spores of the brown rot isolates but not the white rot fungi, and C16 lacked effect on all fungi at all concentrations. C5 and C6 destroyed spores only at 10³ ppm.
E L Schmidt

Effects of a chitin synthesis inhibitor on spore germination of the decay fungi Gloeophyllum trabeum and Poria tenuis
1986 - IRG/WP 2253
This study sought to determine the effect of a chitin synthesis inhibitor - Polyoxin D, on spore germination and early hyphal development of a brown rot and a white rot fungus in-vitro. Polyoxin D is a competitive, substrate-analogue type of chitin synthtase inhibitor (2). The drawbacks to use of such a compound as a wood preservative tie. cost - $20,000/g, possible leaching or degradation) might be reduced should it be effective in preventing decay initiation by spore germination at very low concentrations.
E L Schmidt

Spore germination of Gloeophyllum trabeum on wood is related to the mass of the wood sample
1978 - IRG/WP 2118
E L Schmidt, D W French

Collaborative soft rot tests: 2nd interim report
1975 - IRG/WP 258
J G Savory, J K Carey

Antagonism to spore germination in Scots pine
1990 - IRG/WP 1458
Germination of Lenzites trabea and Chaetomium globosum spores was observed directly on wood blocks, on water soluble extracts and on organic solvent soluble extracts from pine wood. In all cases pine heartwood was found to be antagonistic to spore germination but pine sapwood varied in its antagonism according to the method of drying. Chromatography revealed that extracts from antagonistic wood differed from those of non-antagonistic wood in their composition.
S M Gray

Environmentally more acceptable solvents
1979 - IRG/WP 3131
The subject of this paper is hydrocarbon solvents with particular reference to the cyclo-aliphatic or naphthene-rich, grades which are now available. The specialised low aromatic high boiling petroleum fractions are also discussed.
A M Cumbers

Effect of sterilization method on germination of spores of wood decay fungi observed by contact agar block method
1978 - IRG/WP 2117
Previous studies of germination of spores of wood decay fungi on wood have generally concluded that method of wood sterilization has little significant effect on germination response. This study expands the numbers of test fungi as well as number of sterilization methods employed to determine the influence of sterilization method on spore germination response of decay fungi. Germination was assessed on agar discs fused by aqueous diffusion path to 1 cm³ samples of aspen and white spruce sapwood.
E L Schmidt, D W French

In vitro studies on the effect of chitosan on mycelial growth and spore germination of decay fungi, moulds and staining fungi
2004 - IRG/WP 04-10507
The effect of solubilised, low molecular weight chitosan on established mycelial growth of a range of decay fungi, moulds and staining fungi was investigated using nutrient medium amended with different concentrations of chitosan that ranged from 0.1 to 0.4% weight per volume (%w/v). Also, spore germination of Trichoderma harzianum and Leptographium procerum was examined on chitosan amended nutrient medium using visual and microscopic assessment. The results showed that chitosan affected mycelial growth of a wide range of test fungi which generally showed lower growth rates as the chitosan concentration increased. However, the degree of inhibition exhibited by chitosan varied with fungal species. Under the present test conditions, chitosan was fungistatic, but not fungitoxic, against established mycelium of the staining fungi tested and also two moulds, Botrytis cinera and Cladosporium herbarum, but not against any of the decay fungi tested. Spores of T. harzianum germinated on chitosan amended nutrient medium at all chitosan concentrations tested, except for the highest level (0.2%w/v) used, while L. procerum failed to germinate on 0.15 and 0.2%. Also, T. harzianum and L. procerum spores incubated on 0.15% and 0.2% chitosan failed to germinate when placed onto fresh malt extract agar suggesting fungitoxic activity of chitosan at these higher concentration levels.
C Chittenden, B Kreber, N McDowell, T Singh

Laboratory and field evaluation of Plasmite Reticulation System using bifenthrin as a chemical barrier within wall cavities against subterranean termites.
2005 - IRG/WP 05-20307
Laboratory and field bioassays undertaken to demonstrate Plasmite Reticulation system effectively delivers the termiticide (bifenthrin) within a simulated wall cavity at the required concentration. The chemical assay indicated that the amount of bifenthrin sampled at 5, 10, 15, 20, and 25m along the simulated reticulation system tested (30m) exceeded the manufacturer’s minimum recommendation of 0.0044%m/m. Results of the laboratory bioassay, using Coptotermes acinaciformis, indicated that the concentrations of bifenthrin present in the soil core samples at 5, 10, 15, 20, and 25m were extremely toxic and prevented termite penetration of bifenthrin treated soil in laboratory bioassays immediately after field soil treatment. No penetration of any soil core samples was observed in the field test against Coptotermes lacteus.
J R J French, B M Ahmed, J Thorpe, A Anderson

Correlation between a laboratory bioassay and field trial conducted to determine the termiticidal effectiveness of bifenthrin
2002 - IRG/WP 02-20248
Details are given of a laboratory bioassay and field trial undertaken to determine the termiticidal effectiveness of the synthetic pyrethroid bifenthrin, when impregnated into Pinus radiata D. Don sapwood specimens. Results show a strong correlation between the laboratory and field methods of evaluation. Protection threshold limits obtained were the same for the two test species of termite employed, Mastotermes darwiniensis Froggatt and Coptotermes acinaciformis (Froggatt). Lower and upper threshold limits obtained for M. darwiniensis in both the laboratory and field were 10 and 20 g/m3. The threshold limits for C. acinaciformis were not determined, but must be less than the lowest retentions tested (<2.5 g/m3 in the laboratory and <5 g/m3 in the field).
J W Creffield, K Watson

Germination of basidiospores on preservative treated wood after leaching or natural weathering
1981 - IRG/WP 2150
In tests of residual toxic efficacy after leaching or natural weathering, spore germination with Gloeophyllum trabeum has proved to be a less reliable criterion of attack than when used with unaged preservative treatments. Since spores sometimes prove more tolerant than their parent mycelium, their use should be continued.
J K Carey

A rapid colorimetric assay for mold spore germination using XTT tetrazolium salt
2011 - IRG/WP 11-20462
A rapid colorimetric assay was developed to quantitate metabolic activity in mold spores during germination using 2,3-Bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[9phenyl-amino)carbonyl]-2H-tetrazolium hydroxide (XTT). The assay was used to demonstrate inhibition of spore germination following exposure to different biocides and variability in the inhibition of spore germination of different mold species to the same biocide.
C A Clausen, V W Yang

The possible role of mobile CCA components in preventing spore germination in checked surfaces, in treated wood exposed above ground
2001 - IRG/WP 01-30263
Untreated check surfaces are often exposed in CCA-treated lumber of refractory species used above ground since, during weathering, some checks develop beyond the preservative penetrated zone. However, decay is seldom observed in these checks even after many years of exposure. It is hypothesized that minor amounts of mobile CCA preservative components redistribute during weathering into checks, and that this &apos;surface treatment&apos; prevents fungal spores washed into checks from germinating and causing decay. A substantial amount of copper was found on the exposed check and end-cut surface in exposed wood through the current research, and whether spores are prevented from germinating by this amount of chemical is being studied.
S Choi, J N R Ruddick, P I Morris

Threshold levels for dip treatments of chlorpyrifos for borer control
1995 - IRG/WP 95-10137
Chlorpyrifos has been used in non-pressure treatments of freshly sawn lumber and millwork for ten years or longer to control wood boring beetles. Since chlorpyrifos provides a quick kill of existing beetle larvae at the time of the treatment in solution concentrations as low as 0.05%, treaters tend to use less than recommended rates as a cost saving measure. However, laboratory studies conducted in the United States and Europe have shown that concentrations of 0.5% to 1.0% are needed for residual control. A review of these laboratory studies is presented in this paper.
R D Fears, J L Leca

Effect of fumigant residue in aerated wood blocks on the spore germination of decay fungi
1991 - IRG/WP 2382
Fumigants are increasingly used in several countries for remedial treatments of transmission poles to increase the service life. The present study was initiated primarily to test the remaining toxic effects of spruce (Picea rubra) wood, fumigated with chloropicrin (trichloronitro methane) or MIT (Methyl isothiocyanate) after long period of aeration, on the spore germination of decay fungi. This study indicates that spore germination of decay fungi is more sensitive than mycelia for these fumigants. An assay involving spores could therefore complement the earlier proposed open and closed tube bioassays for assessment of remaining ability to prevent reestablishment of decay fungi in fumigated wood. This assay is sensitive both to bound wood residues contributed by the fumigants as well as to fumigant vapor.
J Bjurman, B Goodell

Estimation of oral toxicity of boron as a bait toxicant and the trophallactic effects between individual members of termite colonies.
2003 - IRG/WP 03-10495
In recent years, because of the favourable environmental characteristics of boron, researchers in the wood preservation industries have refocussed on the use of boron as a major wood preservative against wood-destroying insects. Currently the greatest use of boron compounds is in remedial treatments. Boron has been found to have slow-acting toxicity against subterranean termites. Because of this characteristic, boron compounds may also be used as termite bait toxicants. The effect of boric acid on an individual donor termite was investigated in laboratory bioassays Trophallactic transfer of boron by these individual termites to other orphaned group of termite workers was conducted and the effects on the recipient groups recorded. It was believed that, this sequence of tests would provide a greater understanding of the carrying ability of ‘bait toxicant’ by individual termites, and allow estimates of the threshold toxicity of boric acid and termite survival rates to be determined. The bait matrix was Eucalyptus regnans F. Muell sawdust impregnated with various formulations of boric acid solutions in the laboratory. The result suggests that the toxicity of boron is dose dependent and it critical for the termites to ingest sufficient amounts of boron. But the mode of toxicity of boron has not yet been fully explained.
B M Ahmed

Effect of thickened boron in preventing conidial germination of sapwood-inhabiting fungi
1994 - IRG/WP 94-30059
We evaluated the efficacy of thickened boron preservative "Diffusolä" in preventing conidia germination of sapwood-inhabiting fungi using plate bioassay, Southern Yellow Pine and sweetgum block tests, and green pine log sections. The test fungi were sapstain fungi Ceratocystis coerulescens, Ceratocystis minor, and Aureobasidum pullulans and mold fungi, Aspergillus niger, Penicillium spp, and Trichoderma spp. Conidial germination were inhibited in plate bioassay by Diffusol. Treatment of Southern Pine and sweetgum blocks and green pine log sections with a 10 percent boric acid equivalent of Diffusol inhibited conidial germination of sapstain and mold fungi. In the field exposure, the same Diffusol treatment of green pine log sections inhibited natural basidiospore and conidial germination of forest-inhabiting fungi, thus preventing wood discoloration and deterioration
S C Croan

Inhibitory effects of leachates from Scots pine wood on germination of some wood rotting fungi
1986 - IRG/WP 1282
Leachates from sapwood of Pinus sylvestris inhibited or reduced the germination of basidiospores of the wood decay fungi tested. The fungi were selected among those preferentially colonizing hardwood or softwood, representatives for brown rot and white rot fungi, early basidiomycete colonizers and late basidiomycete colonizers in above-ground parts of pine as well as fungi found in high frequencies in window frames. In contrast, leachates from the heartwood were less inhibitory to germination of the majority of the tested fungi. Wood materials for the tests were selected to reveal differences in inhibitory effect of pine heartwood and sapwood according to: 1. Trees cut in the summer or in the winter 2. Latitude at which the trees had grown 3. Method of drying kiln-dried or air-seasoned wood No differences in inhibitory effect against the test fungi in relation to these different wood materials were revealed.
J Bjurman

Basidiospore structure and germination of Serpula lacrymans and Coniophora puteana
1988 - IRG/WP 1340
Using a nuclear staining technique and fluorescence microscopy, the basidiospores of Serpula lacrymans were shown to be uninucleate whereas those of Coniophora puteana were binucleate. The germination rate of the Serpula lacrymans spores, which was considerably lower than that of Coniophora puteana, decreased further after storage or heat treatment. Transmission electron micrographs indicate that the majority of Serpula lacrymans spores have a disorganised internal cellular structure and are filled mainly with lipidic material; these spores lack a nucleus. Germination of viable Serpula lacrymans spores occurs through the spore apiculus or through the spore apex. In contrast, Coniophora puteana spores can produce two germ tubes and germinate simultaneously through the apiculus and the apex.
B M Hegarty, U Schmitt

Development of threshold values for boron compounds in above ground exposures: Preliminary trials
1998 - IRG/WP 98-30179
Boron is increasingly used both as an initial and remedial treatment for protecting wood against fungal and insect attack. While establishing lethal dosages for boron against insects through feeding tests is relatively simple, establishing thresholds for fungal attack poses more of a challenge. Tests using boron dispersed in agar artificially surround the fungus with both boron and excess nutrients and poorly replicate the wood matrix. Soil or agar block exposures more closely replicate exposure, but these tests also expose the wood to leaching and employ large masses of actively growing fungal mycelium. In practice, however, fungal attack may be initiated by either spores or hyphal fragments that may be far more sensitive to boron. In an effort to develop more accurate thresholds for boron in wood exposed in non-soil contact, we evaluated the ability of hyphal fragments of two fungi, Gloeophyllum trabeum and Trametes versicolor to colonize and decay sapwood and heartwood blocks of Douglas-fir (Pseudotsuga menziesii) treated to retentions between 0.03 and 0.46% boron oxide (wt/wt) in modified petri dish tests. As expected, weight losses were lower in untreated heartwood samples, reflecting the moderate durability of Douglas-fir heartwood. Thresholds for sapwood and heartwood for both fungi were between 0.08 and 1.0% BAE and there appeared to be little effect of the heartwood on the resulting toxic threshold values for boron. These values illustrate the sensitivity of hyphae to boron and imply that higher concentrations may not be necessary for protecting wood from fungal attack in true above ground exposures protected from rainfall.
J J Morrell, C M Freitag, S Unger

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