Primary screening of bacterial antagonist strains to the sunflower dry rot pathogen Rhizopus oryzae.

To develop environmentally safe multifunctional biological preparations, we carried out the primary screening of bacterial strains (from the collection of the biomethod laboratory of V.S. Pustovoit All-Russian Research Institute of Oil Crops) against the sunflower dry rot pathogen Rhizopus oryzae Went & Prins. Geerl. by the method of double or reciprocal cultures. 17 strains of the Bacillus genus exhibited antagonistic activity against the sunflower dry rot pathogen with two types of mechanism of action (competition for feeding area and antibiosis). Strains 01 kor f and D 1-1 Bacillus sp. competed for surface feeding area and inhibited the growth of aerial mycelium of the pathogen. We observed the maximum sterile zone in three strains: 3-3 Bacillus sp. and K 1-1 B. subtilis – 4.0 mm, and P-9 B. polymyxa – 3.0 mm. 6 bacterial strains of the genus Pseudomonas had antagonistic activity against the dry rot pathogen with one type of mechanism of action – antibiosis. Strain 12-2 Pseudomonas sp. had the largest sterile zone on potato sucrose agar (PSA) (5.5 mm), and strains 14-4 and 15-1 Pseudomonas sp. had the largest sterile zone on the King B medium (5.0 and 6.0 mm). [ABSTRACT FROM AUTHOR]