The activities of enzymes such as cellulase, pectinase, proteinase, chitinase and acid phosphatase produced in vitro by T. terrestris and H. crustuliniforme, as well as the activity of ß-glucosidase in roots of inoculated Scots pine seedlings, were studied. In pure cultures an isolate of T. terrestris produced nine of ten enzymes, whereas an isolate of H. crustuliniforme produced only five enzymes. The activity of enzymes was higher in T. terrestris cultures than in H. crustuliniforme, the only exception being neutral proteinase. It was observed that in roots of seedlings inoculated with T. terrestris levels of ß-glucosidase was about 107 per cent higher activity than in roots of non-inoculated seedlings. The enzyme level in roots inoculated with H. crustuliniforme was 44 per cent lower than in those inoculated with T. terrestris.