Basidiomycete colonization of sterile Douglas-Gr pole sections was monitored over 3- and 6-month exposure periods at four Pacific Northwest sites. Basidiomycetes were isolated from 8.2 percent of cores removed from the pole sections after 3 months of exposure, which suggests that colonization occurs rapidly after the poles are peeled. Postia placenta was the most frequently isolated fungus, followed by Stereum hirsutum, Phanerochaete sordida, and Sistotrema brinkmanii. Postia placenta commonly inhabits decaying Douglas-fir poles in service. Climate conditions were not correlated with colonization rate, and site-specific climate indices were not useful for predicting the risk of fungal colonization. The lack of correlation suggests that fungal colonization of air-seasoning poles is controlled by factors other than temperature and rainfall. Douglas-fir poles are rapidly colonized by basidiomycetes and, even when air-seasoned for short periods, must be sterilized at some point during the treatment process.

Impact bending and breaking radius were used to measure loss in toughness caused by basidiomycetes isolated from wood. Small test pieces were used to accelerate testing. Wide differences were found among, and sometimes within, the 26 species tested. Brown-rot fungi tended to cause greater losses than white-rot fungi, but no consistent difference was found between monokaryons and dikaryons of the same species.

Douglas fir pole sections exposed at four air-seasoning sites in the Pacific Northwest were extensively sampled for Basidiomycotina each year for 3 yr. Poles were rapidly colonized by a variety of Basidiomycotina, but four taxa tended to dominate. Two of these, Antrodia carbonica and Postia placenta, are also important in deterioration of Douglas fir poles in service, while Stereum sanguinolentum is found in wounds on live Douglas fir trees and Peniophora (sensu stricto) spp. are colonizers of woody debris. A. carbonica and P. placenta predominantly colonized the heartwood at the ends and upper halves of the pole sections, whereas Peniophora spp. and S. sanguinolentum were uniformly distributed throughout the pole sections in the sapwood. Although the frequency of isolation of the four fungi varied among sites, colonization patterns were consistent.

On examine l'aptitude de l'isothiocyanate de methyle encapsule dans de la gelatine a eliminer les basidiomycetes et a empecher la reinfestation par ces champignons du bois de sapin Douglas traite par le pentachlorophenol ou un agent CCA

In the Pacific Northwest, freshly peeled Douglas-fir poles are often air-seasoned for 6 to 24 months before preservative treatment. The ability of ammonium bifluoride (ABF) to limit fungal colonization was evaluated by flooding pole sections with saturated solutions of ABF before air-seasoning them for 1, 2, or 3 years at site in Oroville, California; Eugene Oregon; Scappoose, Oregon; and Arlington, Washington. Each year, selected poles were destructively sampled to determine levels of fungal colonization. The results indicate that ABF substantially reduced those levels, especially at the driver, southermost site. ABF treatment can reduce, but not eliminate, the risk of fungal colonization during air-seasoning.

A small-scale test was developed to evaluate the ability of fungicides to control decay fungi established in wood. The test, which uses blocks 2.5 x 2.5 x 10 cm, tests the ability of a chemical to migrate from the middle of the block to control a previously established decay fungus, Poria carbonica. The effect of block size, degree of fungal development, chemical exposure period, and aeration during exposure were evaluated on chemicals previously shown to be effective for remedial control of decay. The method was then used to evaluate potential decay control chemicals. Highly volatile chemicals proved to be most effective, while water-soluble and oil-borne chemicals produced much poorer control. The small block tests appear to provide a simple, rapid, and accurate method for predicting how chemicals will control established decay fungi in wood.

Sodium n-methyldithiocarbamate, chloropicrin, and methylisothiocyanate were tested for their ability to protect untreated Douglas-fir posts from decay and insect attack. Removal of increment cores for culturing and bioassays indicated that fumigants slowed, but did not prevent, Basidiomycete colonization. All posts contained surface decay after 4 years and termite attack after 10 years of exposure in ground contact. Pilodyn tests indicated that mechanical properties of all posts also declined, regardless of treatment, although MIT-treated posts declined least. The results suggest that fumigant treatment cannot completely protect non-pressure-treated Douglas-fir from decay but may be useful for low-stress applications, such as for fence posts. Fumigant treatment is not a substitute for proper pressure treatment where service conditions are severe. © 1988, Walter de Gruyter. All rights reserved.

A method for observing germinating fungal spores on wood was developed in which temperature and wood moisture content could be easily controlled and subsequent wood colonization could be determined. Thin radial sections of Douglas fir (Pseudotsuga menziesii) heartwood (8 mm x 8 mm x 60 mu m) were inoculated with a spore suspension and a similar wood section was placed over the inoculated section forming a ''spore sandwich''. The ''spore sandwiches'' were incubated between larger blocks of Douglas fir heartwood to maintain control of the wood moisture content during incubation in controlled temperature-humidity chambers. Spore germination was observed by opening the ''spore sandwiches'' and staining the spores in situ for microscopic observation. Wood colonization was determined by isolations from the surrounding wood blocks. The ''spore sandwich'' method was used to study the influences of temperature and wood moisture content on spore germination of Poria carbonica. Basidiospores and asexual spores germinated and colonized wood at and above the fibre saturation point (c 30% moisture content), but not below. Both spore types germinated and colonized wood at 22 and 30 degrees Centigrade, but basidiospores failed to germinate at 5 and 35 degrees, whereas asexual spores germinated at 5 and 35 degrees, butmore » were unable to colonize the wood. The ''spore sandwich'' method provides a means for assessing spore germination and wood colonization by wood decaying fungi under conditions simulating those occurring naturally in wood in service. (Refs. 21).« less

Pachnocybe ferruginea from Douglas-fir utility poles in western Oregon occurred in two forms. Both forms consisted of dikaryotic mycelium that gave rise to brown capitate basidiocarps. However, one form had associated blastic-sympodial conidia, larger basidiocarps, chlamydospores, and a slower growth rate. Single uninucleate basidiospores of both forms produced dikaryotic mycelium with simple septal pores and holobasidia in which karogamy and meiosis occurred. Thus, P. ferruginea has a primary homothallic life cycle. Spores from conidial isolates gave rise to both basidiocarps and the conidial form demonstrating that the conidial form is the anamorph of P. ferruginea. Nevertheless, results suggest that the P. ferruginea variants form a single pleomorphic species corresponding to published descriptions of P. ferruginea, but with an anamorphic stage. The species should be placed in the Chionosphaeraceae.

On etudie les possibilites d'encapsulation de l'isothiocyanate de methyle dans de la gelatine, le degagement de ce fumigant lorsque la capsule est placee dans le bois et l'efficacite de ce systeme pour controler la pourriture de poteaux de sapin Douglas

Biological procedures were developed to obtain fungi from Douglas-fir poles to distinguish between decay and nondecay fungi and to detect preservative or fumigant depletion so that supplemental treatments could be applied before significant reductions in pole strength occurred. Electrical resistance devices appeared capable of detecting advanced decay and measuring fumigant vapor concentrations in poles and will receive further study. Eight decay and 29 nondecay fungi were obtained from 3,111 Douglas-fir poles in western Oregon. Decay fungi rarely were obtained whereas nondecay fungi frequently were obtained from cedar and southern pine poles. Of the five most prevalent nondecay fungi in Douglas-fir poles, one was quite resistant to chloropicrin. Since this fungus inhibits the growth of a decay fungus in wood, the potential exists for a combined chemical-biological control of internal decay.

Polygalacturonase (EC 3.2.1.15) produced by Fursarium oxysporum f. sp. lycopersici was purified by chromatography on DEAE-cellulose, CM-cellulose, and hydroxyapatite. The purified enzyme consisted of two electrophoretically distinct “isozymes”, that behaved as charge isomers during electrophoresis in several different concentrations of polyacrylamide gel. The two isozymes had similar “endo” modes of action on polygalacturonic acid, as determined by comparison of viscosity reduction, reducing group release, and thin-layer chromartography of oligomeric hydrolysis products. Both isozymes hydrolyzed 5% of the substrate bonds in reaching 50% viscosity reduction. The amino acid compositions of the isozymes were similar and their molecular weights were about 37 000 as determined by sedimentation equilibrium. Removal of large amounts of carbohydrate during purification did not affect heat stability of the enzymes. A large proportion of the remaining carbohydrate appeared to be covalently linked to the enzyme protein.