## 3 Results and Discussions
### Verticillium wilt of horseradish Roots Depending on the Studied Factors
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Year**} & \multicolumn{8}{c}{**Months**} & \multicolumn{2}{c}{**Total/Mean**} \\ \cline{2-9}  & **III** & **IV** & **V** & **VI** & **VII** & **VIII** & **IX** & **X** \\ \hline \multicolumn{9}{c}{Precipitation total [mm]} \\ \hline
2015 & 29.7 & 21.7 & 29.4 & 76.5 & 42 & 35.7 & 41.1 & 35.8 & 311.9 \\
2016 & 35.2 & 38.3 & 64.9 & 71.5 & 133.7 & 27.5 & 22.7 & 99.9 & 493.7 \\
2017 & 50.4 & 58.4 & 56.4 & 128.8 & 61.1 & 53.5 & 185.4 & 88.7 & 682.7 \\
1971–2010 & 32.6 & 38.1 & 53.8 & 70.8 & 82.5 & 66.2 & 51.3 & 39.3 & 434.6 \\ \hline \multicolumn{9}{c}{Mean air temperature [\({}^{\circ}\)C]} \\ \hline
2015 & 5.1 & 8.4 & 13.2 & 16.7 & 20.1 & 22.8 & 15.4 & 7.5 & 13.7 \\
2016 & 4.0 & 8.7 & 14.7 & 18.4 & 18.9 & 18.0 & 16.0 & 7.7 & 13.3 \\
2017 & 5.9 & 7.1 & 13.4 & 17.1 & 18.1 & 19.3 & 13.4 & 10.1 & 13.1 \\
1971–2010 & 2.9 & 7.7 & 13.3 & 16.0 & 17.7 & 17.5 & 13.0 & 8.3 & 12.1 \\ \hline \multicolumn{9}{c}{Sielianinov hydrothermal coefficient [K]} \\ \hline
2015 & 0.9 * & 0.7 & 1.5 & 0.7 & 0.5 & 0.9 & 1.5 & \\
2016 & 1.5 & 1.4 & 1.3 & 2.3 & 0.5 & 0.5 & 4.2 & \\
2017 & 2.7 & 1.4 & 2.5 & 1.1 & 0.9 & 4.6 & 2.8 & \\ \hline \multicolumn{9}{c}{\({}^{*}\) K \(\leq\) 0.4—extremely dry month; 0.4 \(<\) K \(\leq\) 0.7—very dry; 0.7 \(<\) K \(\leq\) 1.0—dry; 1.0 \(<\) K \(\leq\) 1.3—quite dry; 1.3\(<\) K \(\leq\) 1.6—optimal; 1.6 \(<\) K \(\leq\) 2.0— moderately humid; 2.0 \(<\) K\(\leq\) 2.5—humid; 2.5 \(<\) K \(\leq\) 3.0—very humid; K \(>\) 3.0—extremely humid [60].} \\ \end{tabular}
\end{table} 
Table 2: Precipitation totals and mean air temperatures at 2 m above sea level, in the growing months in the years 2015-2017, in the Siemkowice region (according to the Institute of Meteorology and Water Management National Research Institute in Poznár). In the opinion of [PERSON] et al. [31], insufficient information on the etiology of this disease is the main reason for the lack of effective preparations to combat it. Although seedling treatment appears to be the first and best choice when it comes to protection against soil pathogens, there is also a marked lack of research in this field in the literature on the subject. The weather conditions in the growing season strongly determined the severity of the disease and the effectiveness of the protection treatments. The interaction between the years and protection treatments turned out to be significant (Figure 1). It was demonstrated that in the growing season (2017) with generally the lowest DSI, the applied protection treatments, except for BPEm, protected the horseradish roots against Verticillium will to equal extent. On the other hand, in 2015, a year characterized as dry and warm, the most intensive development of the disease was recorded, whereas there was no protective activity in BPBs and BPPo plots. In particular, it was the water deficit, persisting after planting horseradish seedlings and for the next two months, that contributed to this (Table 2). In the conditions of soil drought, the BCA (_B. subtilis_ and _P. oligandrum_) did not protect the roots against pathogens causing Verticillium wilt of internal roots. The study showed that in such conditions, the best protective effect against Verticillium wilt of horseradish roots was achieved in the BPEm plot, where seedling treatment with _E. maxima_ extract was supported by additional foliar application of biostimulants and biopreparations (Figure 1). It is worth noting that in 2015 also the option of protecting with a reduced amount of chemicals (RChP) protected against Verticillium wilt of horseradish roots significantly more effectively than the ChP. Therefore, in horseradish cultivation, there is a chance to minimize the number of treatments performed with synthetic fungicides without reducing the effectiveness of root protection. [PERSON] [61] points out that periods of extreme drought have become a dirle problem for horseradish grows in Poland in recent years. Thus, it is reasonable to use the _E.