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How to keep coated wood structures sufficiently dry to avoid damage caused by rot
1991 - IRG/WP 2376
During the last ten years, a new type of problems with wood rot has emerged in Scandinavia. Thousands of houses have been damaged by wood rot attaching to the exterior wood panel. This paper provides an overview of finished and ongoing work in order to identify the cause of these problems. In field tests, the moisture conditions were measured in panels coated with different paint systems. The influence of the panel structure and end-grain sealing on the moisture balance was also studied. The results from these tests show a large difference in the moisture balance between panels with different exterior wood coatings. In laboratory tests, the transmission of water vapour through paint films was measured using a modified cup method, which provides more realistic conditions for coated wood than the common cup method. One interesting observation made in the studies reported here is that latex paints seem to be much more permeable at high levels of relative humidity than earlier research has shown.
S Hjort

Micromorphology of decay in Keruing heartwood by the basidiomycetes Phellinus contiguus and Dacrymyces stillatus
2002 - IRG/WP 02-10454
This study aimed to characterise the micromorphology of fungal decay in a wooden handrailing in an above ground exposure at the Thames embankment in London. Keruing heartwood (Dipterocarpus spp.) was determined as the construction timber and the two basidiomycetes Phellinus contiguus and Dacrymyces stillatus identified as main decay organisms. Their decay patterns within Keruing heartwood were studied using light microscopy. Besides typical white and brown rot decay features the analysis also revealed cavities in the fibre S2 wall layers. A laboratory screening test with monocultures of both fungi confirmed their individual ability to form rhomboidal shaped cavities similar to those commonly associated with “true” soft rot fungi. This form of attack indicates that typical soft rot-like cavities can also be formed by white and brown rotting basidiomycetes facultatively and are therefore not an absolute indication for the occurrence of soft rot causing asco- and deuteromycetes respectively.
G Kleist, M Ray, R J Murphy

Resistance of acrylic paints on wood against growth of the rot fungus Dacrymyces stillatus
1990 - IRG/WP 2345
In the last few years the presence of the rot fungus Dacrymyces stillatus has been repeatedly confirmed in external wood panels, particularly from wood painted with water based paints. A laboratory method for testing of the fungal resistance of paint films on wood has been developed.This method has been used to test the efficacy of the fungicides Parmetol DF 18 and Parmetol HF 25 against attack by Dacrymyces stillatus. Recent findings regarding factors of importance for fungal attack of painted wood are also discussed.
J Bjurman

Antagonistic effects of Dacrymyces stillatus against growth of other fungi
1991 - IRG/WP 2363
The antagonistic effects in dual cultures on malt extract agar of 5 wood decay fungi and the antagonistic effects of Dacrymyces stillatus against 1 mould fungus and 1 blue stain fungus were determined. Dacrymyces stillatus was the only fungus which exhibited clear antagonistic effects. The effects of Dacrymyces stillatus against the different test fungi varied however to a great extent. Dacrymyces stillatus exhibited clear antagonism against brown rot fungi and a weaker effect against a mould fungus and a blue stain fungus. The antagonistic effect against a white rot fungus was weaker in dual culture. Spore germination of the responding white rot fungus Pycnoporus cinnabarinus was completely inhibited on an agar overlay over a culture of Dacrymyces stillatus on malt extract agar. Inhibitory activity was present in extracts.
J Bjurman