The rhizosphere and endophytic bacteria, which comprise the group of microorganisms promoting plants growth (Plant Growth-Promoting Bacteria-PGPB), are used successfully as biocontrol agents against many pathogens. Using  methods based on artificial potato tubers infection provides rather effective model system at early selection stages of evaluation of samples resistance to pathogens. Despite a significant number of papers devoted to the study of plant resistance to potato late blight and alternariose, dealing the issue of resistance of potato cultivars of modern Ukrainian selection to the Fusarium spp. dry rot ware deficiently understood.

The research has conducted in the Industrial Biotechnology laboratory of the Department of Biodiversity and Ecobiotechnology of National University of Life and Environmental Sciences of Ukraine for 2011-2013.

The following biological preparation was performed for protect potato tubers from rot deceases: control - water treatment; Chemical control - Rovral AkvaFlo, biological control - Fitotsyd-R (based on Bacillus subtilis, PE "BTU-Center", Ukraine), Ekstrasol (associative bacteria consortium, Russia, All-Russian Research Institute of Agricultural Microbiology); Planryz (based on the bacteria Pseudomonas fluorescence, made in State Inspection biolaboratory for Plant Protection in Lviv region).The potato tubers of Ukrainian selection: early grades Serpanok and Povin, middle early – Oberig and Zelenuy Gay, middle late - Kalynivka and Buluna, late-season – Chervona Ruta and Dgerelo Poliske were the objects of investigation.

The evaluation of biological efficiency and resistance of potato varieties to Fusarium spp. has studied in artificial infection methods of contamination by conventional methods. The degree of inhibition of pathogens growth expressed as a percentage and calculated by the formula Abbott. Statistical analysis of the results of research conducted using the program of Microsoft Excel.

The significant differences in the reaction of varieties had deficiently observed in the early stages of the pathological process at the inoculation of tubers by Fusarium sp. However, the symptoms appeared on the second day in the relatively susceptible varieties Povin and Oberig in a dull grayish-brownish spots, slightly dented inward and visible light sclerostenosis tuber. The disintegration of tissues and destruction of cells of resistant varieties Serpanok and Poliske Dzerelo were observing for 3-4 days.

The application of microbiological preparations Ekstrasol, Fitotsyd-R and Planryz proved effective in delaying the progression of Fusarium sp. dry rot. The disease progression slowed in 1, 4-1, 9 times in tuber tissue treated with biologic preparation. The biological effectiveness ranged from 32, 2 to77, 1% for the 2nd day in the relatively susceptible varieties Kalynivka and Povin, the remaining grades - 13, 3-39,4%. The efficiency of biological preparations against rot decreased for two weeks to a slight degree, it was in averaged 25.5% on the 15-day of study.

Biological preparations are slightly given up of chemical control – Rovral Aqvaflo, and in some cases, delayed disease progression even greater extent. In most resistant varieties Serpanok and Poliske Dzerelo the area of inoculation for 15 days was in control 9, 6-12, 2% compared to the relatively susceptible varieties Oberig and Povin (17, 8-23, 7%).

Key words: potato, varieties, microbial preparations, stability, Fusarium spp., biological efficiency.