The Effect Of pH On Decomposition Of Mylone® (Dazomet) And Tridipam To Fungitoxic Methylisothiocyanate In Wood

Authors

  • J. J. Morrell
  • C. M. Sexton
  • S. Lebow

Keywords:

Douglas-fir, wood decay, Poria carbonica, Poria placenta, utility poles, fumigants, Mylone®, tridipam, methylisothiocyanate, pH, buffers

Abstract

Mylone® and tridipam are two solid chemicals that decompose to produce methylisothiocyanate (MIT), a highly effective wood fumigant. In this study, two techniques—a rapid, test-tube method and a small-scale, wood-block assay—were used to determine the effect of the pH of various chemical buffers on the decomposition of Mylone® and tridipam in Douglas-fir heartwood samples colonized by Poria carbonica. Both chemicals were sensitive to pH, and higher levels of MIT were produced as the pH of the buffers increased. In general, fungal survival was not affected I week after chemical treatment. Complete control of P. carbonica, however, resulted after 4 weeks of exposure to 50 mg Mylone®/block or 150 mg tridipam/block, when each chemical was combined with a pH-12 buffer.

These results suggest that regulating fumigant treatments according to the degree of fungal attack can substantially improve the precision of decay control in wood maintenance programs.

References

Clarke, A. J., and A. M. Shepherd. 1966. The action of Nabam, metham-sodium, and other sulfur compounds in Heterodera schachtii cysts. Ann. Appl. Biol. 57:241-255.nElson, J. E. 1966. Fungitoxicity of sodium N-methyldithiocarbamate (Vapam) and its decomposition products. M.A. thesis, Oregon State University, Corvallis, OR. 35 pp.nEslyn, W. E., and T. L. Highley. 1985. Efficacy of various fumigants in the eradication of decay fungi implanted in Douglas-fir timbers. Phytopathology 75:588-592.nGoodell, B. S., and R. D. Graham. 1983. A survey of methods used to detect and control fungal decay of wood poles in service. Int. J. Wood Presrv. 3(2):61-63.nGoodell, B. S., R. L. Krahmer, and R. D. Graham. 1980. Chloropicrin movement and fungitoxicity in a decaying southern pine laminated timber. For. Prod. J. 30(12):39-43.nGraham, R. D. 1973. Preventing and stopping internal decay of Douglas-fir poles. Holzforschung 27(5):168-173.nHand, O. F., P. A. Lindgren, and A. F. Wetsch. 1970. The control of fungal decay and insects in transmission poles by gas phase treatments. Branch Laboratory, Bonneville Power Administration, Vancouver, WA. 28 pp.nHelsing, G. G., J. Morrell, and R. D. Graham. 1984. Evaluations of fumigants for control of internal decay in pressure-treated Douglas-fir poles and piles. Holzforschung 38(5):277-280.nKlopping, H. L., and G. J. M. Van Der Kirk. 1951. Investigations on organic fungicides. IV. Chemical constitution and fungistatic activity of dithiocarbamates, thiuram sulphides, and structurally related compounds. Rec. Trav. Chim. Pays-Bas Belg. 70:917-939.nMorrell, J. J., and M. E. Corden. 1986a. Controlling wood deterioration with fumigants: A review. For. Prod. J. 36(10):26-34.nMorrell, J. J., and M. E. Corden. 1986b. Conserving energy by safe and environmentally acceptable practices in maintaining and procuring transmission poles for long service. Sixth Annual Report. Cooperative Pole Research Program, Oregon State University, Corvallis, OR. 100 pp.nRicard, J. L., T. E. See, and W. B. Bolen. 1967. Control of incipient decay with gases in Douglas-fir poles. For. Prod. J. 18(4):45-51.nRuch, J. E., and J. B. Johnson. 1957. Crag Mylone: An investigation of its degradation in soil. Unpublished report. Stauffer Chemical Company, Stamford, CT.nThorn, G. D., and R. A. Ludwig. 1962. The dithiocarbamates and related compounds. Elsevier Publishing Co., New York, NY. 298 pp.nTurner, N. J. 1962. Decomposition of sodium N-methyldithiocarbamate, Vapam, in soil. Ph.D. dissertation, Oregon State University, Corvallis, OR. 45 pp.nZahora, A. R. 1983. Methylisothiocyanate as a wood fumigant: Fungitoxicity to Poria carbonica in wood and gelatin encapsulation for use in wood products. M.S. thesis, Oregon State University, Corvallis, OR. 65 pp.nZahora, A. R. and M. E. Corden. 1985. Gelatin encapsulation of methylisothiocyanate for control of wood decay fungi. For. Prod. J. 35(7):64-69.n

Downloads

Published

2007-06-22

Issue

Section

Research Contributions