Studies of the mycoparasitism in rhizosphere of emerging sugar-beet.

Pythium oligandrum Drechsler was found as a very weak pathogen of emerging sugar-beet by means of the inoculation of the sterilized soil. The hyperparasitic ability of Pythium oligandrum Drechsler to relative species, viz. Pythium ultimum Trow and Pythium debaryanum (Hesse) were proved in rhizosphere of emerging sugar-beet. The rhizosphere soil inoculation by P. ultimum resulted in the sugar-beet emergence about 3% while the sugar-beet emergence achieved 110% if P. ultimum and P. oligandrum were inoculated simultaneously. The sugar-beet emergence due to the dual inoculation of rhizosphere soil by P. ultimum and P. debaryanum was about 3%, whereas due to P. ultimum, P. debaryanum, and P. oligandrum 77%.