Joinery timber in outside use becomes affected by blue-stain after a short time of exposure. This is especially the case with pine sapwood treated with unpigmented lacquer, but also with other timber species as well as different types of surface treatment. According to the basic investigations of BUTIN this is due to special types of blue-stain fungi, called "Lack-bläue" (lacquer blue-stain), in contrary to blue-stain fungi living in roundwood or on sawn timber. The most important species in painted joinery timber were Aureobasidium pullulans (de Bary) Berkh. and Sclerophoma pityophila (Corda) v Höhn. The former fungus is also described as a common species on timber in outside use without any surface treatment. Special fungicides are necessary to prevent blue-stain on joinery timber. Wood preservatives which give good protection against Basidiomycetes often fail against blue-stain fungi. Formulations for prophylactic treatment of logs and sawn timber are also not suitable since there are different kinds of fungi and service conditions. Furthermore, preservatives for joinery timber have to last for a long time in contrast to the short prophylactic treatment. As a result of these specific conditions special test methods are necessary to evaluate the effectiveness of fungicides and wood preservatives to prevent bluestain of worked wood in service.

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