In 2017 an experiment was carried out on the potato plant, where the purpose was to study the effect of Rhizoflo Premium on the appearance of harmful organisms, namely the colorado potato beetle, and two diseases, black leaf spotting (Alternaria solani) and potato mold (Phytophthora infestans). Rhizoflo Premium is a new generation product formulated from two bacterial isolates - Pseudomonas fluorescens and Azospirillium brasilense. Both of them belong to the rhizobacteria (PGPR), which are bacteria in the immediate vicinity of the roots of plants in the soil. Rhizobacteria fulfills criteria such as competitive root colonization, stimulating plant growth and inhibiting pathogenic microorganisms. The experiment was carried out on the Laboratory field of the Biotechnical Faculty in Ljubljana on the surface of 1279.8 m2. Three varieties were included in the experiment, 'Morgana', 'Sunita' and 'Primabelle', 1/3 of the potatoes were pre-soaked with the 'Rhizoflo' preparation, 1/3 were sprayed with Rhizoflo and 1/3 was not treated. We found that the effect of the Rhizoflo Premium preparation was a higher yield for treated tubers, as the final yield was significantly higher in soaked (average 40,43 t/ha) and sprayed tubers (average 34,65 t/ha) compared to control (average 32,75 t/ha). In the inventory of harmful organisms, we found that it did not have any influence on the differences in abundance between the treatments, since the presence of certain developmental phases of the Colorado beetle and the symptoms of the diseases varied between the treatments.