Yeast and bacteria as biological control agents against fungal discolouration of Pinus sylvestris blocks in laboratory-based tests and the role of antifungal volatiles

This paper reports on the use of yeast as biological control agents against mould and blue-slain fungi in laboratory-based Pinus sylvestris sapwood wo od block incubation rests. All 5 yeast isolates tested significantly reduce d discolouration of wood surfaces by moulds and most were also effective ag ainst staining fungi. The 2 most promising yeast isolates also significantl y reduced radial growth of selected mould and stain fungi in vitro solely t hrough the liberation of volatile compounds. Five bacterial isolates were a lso tested fur antagonism toward mould and stain fungi and were effective b iological control agents in wood block tests. Again, volatile production al one by the bacteria was shown to be sufficient to significantly reduce fung al growth in vitro. Most of the bacteria and yeasts significantly reduced w ood discolouration by fungi when inoculated onto block surfaces 7 days befo re, or at the same time as the target Fungi, and in some cases even when in oculated 7 days after the fungi. The possibility of using yeasts as biologi cal control agents to prevent wood spoilage during kiln drying and short-te rm storage at sawmills is considered.