Mould and staining fungi

A few studies have been performed examining the resistance of acetylated wood to mould and stain fungi in a laboratory environment (Wakeling etal., 1991, 1992). These studies found that acetylation reduced the rate of mould growth, but at the end of the test there was no difference in the extent of colonization. Furthermore, samples modified to a WPG of 10 % exhibited a higher rate of colonization for reasons that were not clear. Samples acetylated up to a WPG of 20 % did not exhibit any improvement in performance in terms of mould growth, compared to unmodified samples, when exposed in a field trial. 

Wakeling, A.N., Plackett, D.V. and Cronshaw, D.R. (1991). The susceptibility of acetylated Pinus radiata to mould and stain fungi. In Proceedings of the International Symposium on Chemical Modification of Wood, Kyoto, Japan, Takahashi, M. (Ed.), pp. 142-147. 

Phenylsulphamide fungicides II, 16.]. There are two phenylsulphamide preservatives that have been evaluated and used as components of wood preservative formulations dichlofluanid [II, 16.5.] and tolylfluanid [II, 16.6.]. Both of these active ingredients target the mould and stain fungi, and have been used as components to control stain and mould in organic solvent-based systems, and in particular, for joinery (millwork) applications. However, they have very limited stability in water-based systems. 

Pentachlorophenol and its salt, sodium pentachlorophenate, are used primarily as wood preservatives on telephone poles, pilings and fence posts. In Europe, pentachlorophenol and its derivatives, sodium pentachlorophenate and pentachlorophenyl laurate are used to control sap stain in green lumber. It is also used in Europe on millwork to prevent the growth of mould and fungi, and as a preservative for waterproof materials (i.e., tarpaulins) that are used in outdoor applications. In the United States, it is used almost entirely for treatment of utility poles (Agency for Toxic Substances and Disease Registry, 1994). 

For sapstain treatment (protection of freshly cut and sawn timber against staining fungi and superficial moulds) borax is used in mixture with other fungicides, in particular with sodium pentachlorophenate (Section 5.6.3), but with sodium phenylphenolate (Section 5.4.1) or with quaternary ammonium compounds (Section 16.1) too. 

Dichlofluanide has a broad spectrum of activity (see Table 110) which also covers mercury resistant Penicillium species, but not Trichoderma viride. It is particularly effective against wood-staining fungi (blue stain mould) and therefore one of the most important fungicides in non-film forming decorative wood stains, in wood coatings and primers. 

Eukaryotes, In contrast to prokaryotes, possess a cell nucleus and organelles, e.g. mitochondria or microbodies. Bacteria are prokaryotes, the Gram-staining characteristics of which provide information about the construction of the bacterial cell wall. Fungi are eukaryotes, which grow as single cells and are then termed yeasts, or moulds, which exhibit a filamentous structure (hyphae). 

In accordance with its extraordinary high toxicity for fungi the active ingredient is mainly used as a fungicide, e.g. for paint film protection, in non-film forming decorative wood stains, in the leather industry for the protection of wet blues, in adhesives and sealants, pulp, paper and cardboard, etc. Surface coatings treated with the fungicide may lose mould resistance when exposed to... 

Benzimidazole fungicides. Of the benzimidazole fungicides, both thiabendazole [II, 15.9.] and carbendazim [II, 11.4.] have been evaluated as components of wood preservative formulations. Of these, carbendazim has been valued for its activity towards stain and mould fungi, particularly in combination with chlorothalonil as noted above. Carbendazim (a breakdown product of benomyl [II, 11.5.]) has very low solubility in most solvents and therefore is most commonly applied as a dispersion in antisapstain treatments. Carbendazim is however soluble at lower pH (as an acid salt), and has been used as a mould control agent in CCA treatment solutions. Acid salts of carbendazim (hydrochloride and phosphate) have been used in the treatment of Dutch elm disease. 

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