The diploma thesis deals with modern protection methods of coniferous seedlings against the maturation feeding caused by large pine weevil (Hylobius abietis), with a focus on biological protection using entomopathogenic fungus Beauveria bassiana. Forest areas after extensive disasters caused by natural disturbances, are increasingly attacked by this physiological pest. Unsuccessful attempts to reforest these areas as the impact of the pest, require considerable financial costs as well as adverse impacts on the landscape. The European Union and its legislative support utilizing of an integrated pest management to protect forests against the pests without using of chemical protection. The aim of this work was to verify the effectiveness of biological protection of seedlings by using an entomopathogenic fungus Beauveria bassiana, as an alternative to the used insecticides. The thesis presents results from the latest experiments carried out in laboratory as well as in natural conditions. The main one is the ability of the entomopathogenic fungus Beauveria bassiana to reduce the abundance of the large pine weevil populations directly in the field.