Synergistic Wood Preservatives: Terrestrial Microcosms (TMCs) and Field Exposure Efficacy Studies of the Synergistic Copper: Pyrithione Mixture


  • Tor P. Schultz
  • Thomas Nilsson
  • Darrel D. Nicholas


Copper, field exposure, fungi, pyrithione, termites, terrestrial microcosms (TMCs), tunneling bacteria, wood preservation


On the basis of short-term laboratory tests using various wood decay fungi, we previously found that the mixture of copper (II) and sodium pyrithione is highly synergistic. In this study we examined the efficacy of this mixture in protecting wood using terrestrial microcosms (TMCs) with three different Swedish soils, and field stake (ground contact) tests in two different locations in Mississippi. After 12 months of exposure in TMCs, the copper: pyrithione mixture was found to be more effective than either component alone, with only slight degradation due to tunneling bacteria in a compost soil TMC. The field stake test, after 6 years of exposure, showed that a mixture of 0.31 pcf or greater copper (as CuO) and 0.063 pcf or greater pyrithione (as the sodium salt) was approximately as effective as about 0.35 pcf CCA in preventing fungal and termite degradation.


AWPA Standards. 1997. American Wood-Preservers' Association Standards 1997. Gransbury, TX.nDietrich, W., E. Giebeler, G. Geromin, and W. Weiss. 1987. Synergistic wood preservatives comprising quaternary ammonium compounds and pyridine N-oxide derivatives. German Patent Application: DE 87-3718012.nEdlund, M.-L. 1998. Durability of wood in ground contact tested in field and laboratory. Doctoral thesis, Swedish University of Agricultural Sciences, Uppsala, Sweden. 24 pp.nEdlund, M.-L., and T. Nilsson. 1999. Performance of copper and non-copper based wood preservatives in terrestrial microcosms. Holzforschung 53:369-375.nHedley, M. E., A. F. Preston, D. J. Cross, and J. A. Butcher. 1979. Screening of selected agricultural and industrial chemicals as wood preservatives. Int. Biodeterior. Bull. 15(1):9-18.nLudwig, G. W., O. Exner, and H. G. Schmitt. 1991. Synergistic wood preservative compositions comprising phenol and pyrithione derivatives. German Patent Application: DE 91-4122654.nMcCoy, M. 1998. Biocides succeed despite regulations. Chem. Eng. News, Nov. 9, 1998:21-39.nMickelwright, J. T. 1999. Wood preservation statistics, 1997. AWPA, Gransbury, TX.nMorpeth, F. F. 1991. Synergistic industrial antimicrobial compositions comprising an isothiazolone derivative. European Patent Application: EP 91-311043.nNaoki, Y. 1998. Application example of tin replacement agent in ship bottom paint. Toso Gijutsu 37(7):93-96.nNicholas, D. D., and K. J. Archer. 1995. Soil beds for testing wood preservatives. Pages 110-115 in Wood preservation in the '90s and beyond. FPS Proceedings No. 7308, Forest Products Society, Madison, WI.nNicholas, D. D., and T. Schultz. 1995a. Biocides that have potential as wood preservatives—An overview. Pages 169-173 in Wood preservation in the '90s and beyond. FPS Proceedings No. 7308, Forest Products Society, Madison, WI.nNicholas, D. D., and T. Schultz. 1995b. Synergistic wood preservative compositions. U.S. Patent 5,462,589.nNicholas, D. D., and T. Schultz. 1996. Synergistic wood preservative compositions. U.S. Patent 5,540,954.nNilsson, T., and M.-L. Edlund. 1995. Laboratory versus field tests for evaluating wood preservatives: A scientific view. Int. Research Group Paper IRG/WP 95-20076.nPreston, A. F. 1993. Wood preservation: Extending the forest resource. J. Forestry 91(11):16-18.nSchultz, T. P., and D. D. Nicholas. 1995. Utilizing synergism to develop new wood preservatives. Pages 187-191 in Wood preservation in the '90s and beyond. FPS Proceedings No. 7308, Forest Products Society, Madison, WI.nTrotz, S. I., and T. H. Fedynshyn. 1984. Pyrithione-containing bioactive polymers and their use in paint and wood preservative products. U.S. Patent Application: 84-660208.n






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