EN
A Fibroporia gossypium (Speg.) Parmasto fruit-body was found on a Norway spruce [Picea abies (L.) Karst.] stump in the northeast of Poland (Waliły forest district). The mycelium from wood samples was sequenced (KF725876), identified and used to examine: (i) linear growth of the mycelium on malt-extract medium and (ii) the decay of spruce wood samples. We observed slow mycelium growth (84 mm colony diameter after 28 days). After the first 3 months of wood decay, the average loss of dry mass was 6.7%. After next 3 months, a further loss of 15.4% (the average loss) was recorded until finally 35.98% loss (the maximum loss of wood for a single sample) occurred. Fibroporia gossypium can be considered as a protective biological agent against root rot in threatened Norway spruce stands.