Use of pre-sowing soil microbiological analysis to predict the spread of sugar beet root rot

Aphanomyces cochlioides and Rhizoctonia solani are two of the main soil phytopathogens of sugar beet, which lead to substantial losses in yield and quality. Since disease control capabilities are complex and pathogen monitoring is important for predicting risks, it is of great importance in rural production to create available methods for preliminary field assessment. The purpose of the study was to introduce a predictive methodology for assessing the potential of soils for their suitability for growing sugar beet in the system of short-rotation crop rotations. As an indicator plant, sugar beet seeds were used, which are not characterised by genetic resistance against these diseases. The possibility of using the pre-growing disease index (PPDI), which has a gradation from 0 to 100 and covariance with the actual yield, sugar content and gross sugar yield per hectare, is tested. The pre-sowing PPDI value is compared with the actual yield from each specific field to really assess the possibility of using the PPDI index to characterise yield losses on production crops. It is determined that with an increase in the PPDI value, the gross yield of sugar beet, sugar content, and gross sugar yield decreased. The results of studies show that one unit of PPDI causes a loss of gross yield at the level of 0.24 t/ha and a decrease in the sugar harvest by 0.018 t/ha. That is why, to manage the risks of growing sugar beet, it is necessary to assess the phytopathogenic load of the soil. It is established that the most harmful and permanently identified phytopathogens are Rhizoctonia solani and Fusarium ssp, which indicates the need to select hybrids that are characterised by resistance or high tolerance to these pathogens. The information obtained can be used for timely identification of infection risks, development of effective management strategies, and improvement of agricultural techniques for growing sugar beet to reduce crop losses and increase the efficiency of agricultural products