In the Republic of Belarus as well as in the world acute problem of protecting forests from diseases and pests. The damage caused by root rot is essential, therefore, the problem of forest protection is an urgent task. The biologics has the greatest prospects in according with traditional methods of struggle. Deep method of cultivation of a mushroom Phlebiopsis gigantea with use of nutrient mediums on the basis of ethanol stillage and its components (fugat) is researched. Feasibility of use stillage as raw materials in production of a biological product for the wood protection against root decay is shown. The effect of different additives (sawdust, fodder yeast) on the accumulation of reactive biological product - oidy has been studed It was determined that the deep cultivation using sawdust of the highest accumulation oidy (1.5 <TEX>$10^6units/ml$</TEX>). It was also found that the stillage is the best breeding ground for fungus biomass accumulation (7.9 9.8 g / l) versus fugat (6.0 6.6 g / l). On the basis of research work the technological scheme for production of a biological product were developed. Based on the conducted studies, a technological scheme was proposed for obtaining a biological preparation by deep cultivation of the fungus Phlebiopsis gigantea.