Susceptibility of painted wood to Aureobasidium pulluians: fungal stain and growth patterns

Wooden blocks of Norway spruce were coated with different paint formulations. Water- and solvent-borne model and commercial paints were used. The coated wooden blocks were inoculated with a spore suspension of Aureobasidium pullulans (de Bary) Arnaud and placed in an environment of high humidity for 14 months. Different levels of fungal stain and variable growth patterns were observed on the different coated samples. Fungal growth in the form of hyphae was observed on the paints that became heavily stained, and yeast-like cells occurred on the paints that became less stained by the fungus. Towards the end of the incubation period commercial paints containing a fungicide became more stained than the same paint formulations without fungicide.