The cultivation of cruciferous crops is threatened by extensive yield losses caused by the soil-borne pathogen Plasmodiophora brassicae Woronin, 1877. The objective of the study was to assess the potential of the bacterial product BactoMix 5 for the control of clubroot on a naturally infested soil in growth chamber trials using a P. brassicae-specific qPCR methodology. The results did not show a significant decrease in the P. brassicae in the soil nor a reduction of the disease symptoms on the plants. The native soil microbiota may have exhibited an antagonistic activity against the bacterial species from BactoMix 5 and evoked the poor effect of the product. Therefore, potential biological control agents should be tested with native soil microbiota and the regional production should be advanced to increase the product efficacy in the environment