The Role of Selected Deuteromycetes in the Soft-Rot of Wood Treated with Pentachlorophenol


  • Jonathan D. Lew
  • W. Wayne Wilcox


Soft-rot, Trichoderma, Scytalidium, Fusarium, Douglas-fir, Pseudotsuga menziesii, poles, pentachlorophenol, liquefied petroleum gas, Deuteromycetes, fungi


The severity of soft-rot in a group of Douglas-fir transmission poles treated with pentachlorophenol (PCP) carried in a liquefied petroleum gas (LPG) cosolvent system was assessed at the cellular level using phase contrast and polarized light microscopy. The principal fungi involved in the surface deterioration of the poles were isolated, identified, and tested for their tolerance to PCP in synthetic culture media and for their ability to produce weight-loss and/or soft-rot cavities in wood blocks treated with varying concentrations of PCP.

Two Deuteromycetes, Trichoderma spp. and Scytalidium spp., were common on the pole surfaces despite high retentions of PCP in the outer 1/4-inch zone. Fusarium spp. were isolated with less frequency. All three fungi demonstrated significant tolerance to PCP in agar-plate screening, but only a Scytalidium isolate produced soft-rot cavities under the conditions of the weight-loss test. Soft-rot attack was extremely superficial in these poles, despite the ubiquitous presence of PCP-tolerant Deuteromycetes. After 7-12 years of service life, the depth of degradation due to the action of soft-rot organisms was less than 1 mm in 90% of the poles studied. This observation suggests that this group of poles should provide excellent service life.


American Wood-Preservers' Association. 1978. Poles—Preservative treatment by pressure processes. AWPA Standard C4-78.nArsenault, R. C. 1970. Field and test plot studies of pentachlorophenol stability and its preservative effectiveness in wood treated with liquefied petroleum gas-cosolvent systems and petroleum oil systems Part I. Proc. Am. Wood-Pres. Assoc.66:197-211.nBarron, G. L. 1972. The genera of Hyphomycetes from soil. Robert E. Krieger Publishing Co., Inc., New York. 364 pp.nCowling, E. B. 1957. The relative preservative tolerances of 18 wood-destroying fungi. For. Prod. J.7(10):355-359.nCserjesi, A. J. 1967. The adaptation of fungi to pentachlorophenol and its biodegradation. Can. J. Microbiol.13(3):1243-1249.nCserjesi, A. J., and E. L. Johnson. 1972. Methylation of pentachlorophenol by Trichoderma virgatum.Can. J. Microbiol.18(1):45-49.nDavidson, H. L. 1977. Comparison of wood preservatives in stake tests. USDA Res. Note FPL-02.nDavies, D. L. 1971. Durability of poles treated with penta in an LP gas system. Proc. Am. Wood-Pres. Assoc.67:37-42.nDennis, C., and J. Webster. 1971a. Antagonistic properties of species groups of Trichoderma. I. Production of non-volatile antibiotics. Trans. Br. Mycol. Soc.57(1):25-39.nDennis, C., and J. Webster. 1971b. Antagonistic properties of species groups of Trichoderma. II. Production of volatile antibiotics. Trans. Br. Mycol. Soc.57(1):41-48.nDennis, C., and J. Webster. 1971c. Antagonistic properties of species groups of Trichoderma. III. Hyphal interaction. Trans. Br. Mycol. Soc.57(3):363-369.nDuncan, C. G. 1960a. Soft-rot in wood and toxicity studies on causal fungi. Proc. Am. Wood-Pres. Assoc.56:27-34.nDuncan, C. G. 1960b. Wood-attacking capacities and physiology of soft-rot fungi. U.S. For. Serv., FPL Rep. No. 2173.nDuncan, C. G. 1961. Relative aeration requirements by soft-rot and Basidiomycete wood-destroying fungi. U.S. For. Serv., FPL Rep. No. 2218.nDuncan, C. G. 1965. Determining resistance to soft-rot fungi. U.S. For. Serv. Res. Pap. FPL 48. 12 pp.nDuncan, C. G., and F. J. Deverall. 1964. Degradation of wood preservatives by fungi. Appl. Microbiol.12(1):57-62.nEllis, M. B. 1971. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England. 608 pp.nFrydman, C. 1978. An accelerated method for detecting soft rot in wood. Univ. Calif. For. Prod. Lab. Internal Rep. No. 36.01.110, 4 pp.nGreaves, H. 1977. An illustrated comment on the soft rot production in Australia and Papua New Guinea. Holzforschung31(3):71-79.nHedley, M. E., and P. E. Mills. 1977. Service tests of softwood transmission poles in New Zealand. New Zealand For. Serv. Tech. Paper No. 64. 27 pp.nHenningson, B., T. Nilsson, P. Hoffmeyer, H. Friis-Hansen, L. Schmidt, and S. Jakobsson. 1976. Soft rot in utility poles salt-treated in the years 1940-1954. Swedish Wood Preservation Institute Rep. No. 117E.nHulme, M. A., and J. K. Shields. 1972. Interaction between fungi in wood blocks. Can. J. Bot.50:1421-1427.nHunt, R. S., and F. W. Cobb. 1971. Selective medium for the isolation of wood rotting Basidiomycetes. Can. J. Bot.49:2064-2065.nKäärik, A. 1975. Succession of microorganisms during wood decay. Pages 39-51 in W. Liese, ed. Biological transformation of wood by microorganisms. Springer-Verlag, Berlin. 203 pp.nMcOrmond, R. R., J. Ochrymowych, and R. D. Arsenault. 1978. Pentachlorophenol-liquefied petroleum gas treatment of poles: preservative depletion and performance study. Proc. Am. Wood-Pres. Assoc.74:64-80.nRicard, J. L., and W. B. Bollen. 1968. Inhibition of Poria carbonica by Scytalidium sp., on imperfect fungus isolated from Douglas-fir poles. Can. J. Bot.46:643-647.nSavory, J. G. 1955. The role of microfungi in the decomposition of wood. Proc. Ann. Conv. Br. Wood Pres. Assoc. pp. 3-20.nSavory, J. G., and A. F. Bravery. 1971. Observations on methods of determining the effectiveness of wood preservatives against soft rot fungi. Mitt. Dtsch. Ges. Holzforsch.57:12-17.nSavory, J. G., and J. K. Carey. 1975. Collaborative soft rot tests, 2nd interim report. Int. Res. Group on Wood Pres. Document No.:IRG/WP/258.nSeehan, G., W. Liese, and B. Kess. 1975. List of fungi in soft-rot tests. Int. Res. Group on Wood Pres. Document No.:IRG/WP/105.nStillwell, M. A., F. E. Wall, and G. M. Strunz. 1973. Production, isolation, and antifungal activity of scytalidin, a metabolite of Scytalidium sp. Can. J. Microbiol.19(5):597-602.nStranks, D. W. 1976. Scytalidin, hyalodendrin, cryptosporiopsin—antibiotics for prevention of blue stain in white pine sapwood. Wood Sci.9(2):110-112.nStranks, D. W., and M. A. Hulme. 1975. The mechanisms of biodegradation of wood preservatives. Org. u. Holz.3:345-353.nUnligh, H. H. 1968. Depletion of pentachlorophenol by fungi. For. Prod. J.18(2):45-50.nUnligh, H. H. 1978. Decay resistance of wood treated with fungal antibiotics: cryptosporiopsin, hyalodendrin, and scytalidin. Wood Sci.11(1):30-32.nWilcox, W. W. 1970. Anatomical changes in wood cell walls attacked by fungi and bacteria. Bot. Rev.36(1):1-28.n






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