Effects of water glass and DMDHEU treatment on the colonisation of wood by Aureobasidium pullulans

Specimens of Scots pine sapwood (Pinus sylvestris) and beech (Fagus sylvatica) were treated with a sodium water glass solution and 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU). The pH-values of water glass treated specimens were between 9.7 and 12.0. Those of DMDHEU treated specimens were 3.8 (Scots pine) and 4.2 (beech). The resistance observed in an eight weeks laboratory test against the blue stain fungus Aureobasidium pullulans showed that treatments with water glass and DMDHEU reduced but not prevented the fungal growth. Wood specimens treated with water glass showed the lowest colonisation of blue stain. Both treatments inhibited fungal penetration through the ray cells. HPLC analysis showed that the amount of simple sugars was reduced due to water glass treatment. The amount of simple sugars in DMDHEU treated wood depended on the wood species. The amount of available sugar monomers did not indicate an influence of the colonisation of the sample surface.