The experiment was set up on two types of the soil: Mollic Gleysols (FAO, 1998) and Eutric Cambisols where the presence of pathogenic fungi – sugar beet root decay agent – Rhizoctonia solani has been detected since 2005. In a two year study (2008, 2009), the experiment was set up by completely randomized block design in 4 repetitions and 16 different variants. Two beet varieties, Belinda, sensitive to pathogenic fungi R. solani, and Laetitia, tolerant to pathogenic fungi R. solani), were grown. The microbiological preparation BactoFil was applied in different amounts in autumn and spring. In addition, the nitrogen fertilizer application, based on the results of soil analysis, was varied.
The following parameters were tested: amount of infected and decayed plants, root yield, sugar content, sugar in molasses and sugar yield. The best results were obtained by applying the microbiological preparation BactoFil, and by 30% reduced nitrogen fertilizer application. Preparation dosage and time of application depended on soil properties.
