# Nematoidal Properties of Wild Strains of _Pleurotus ostreatus_
## 3 Results
### The Pot and Field Experiments  
In the pot experiment, all tested oyster mushroom strains inoculated to the soil without plant cultivation contributed to a significant reduction in the population of the beet cyst nematode _H. shachtii_. In the soil without mycelium (black fallow), a 28.1% reduction in the number of nematodes was observed. The mycelia (Po1 5 dix27, Po2 15 dix17, and Po4 2 dix1) introduced into the pots caused a reduction in the population of the beet cyst nematode by 40.9%, 40.2% and 46.9%, respectively (Figure 18). The joint effect of sugar beet plants and Po2 15 dix17 mycelium resulted in a slight increase in the number of _H. schachtii_ eggs and larvae (3.7%). However, significantly, the highest increase in the number of nematodes was observed in the control pots (sugar beet plants without any mycelium), which demonstrated 242.6% of the initial infestation; whereas the soil inoculated with Po1 5 dix27 mycelium and sown with sugar beets demonstrated 238.1% (Figure 19). The Pf/Pi coefficients confirmed the protective role of the mycelia introduced into the soil, showing the best result for the Po4 Buller progeny (Po4 2 dix1), which, even with the combined growth with sugar beet, could decrease the _H. schachtii_ population in the soil (Figure 20).  
\begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{2}{c}{**Elements of Cluster 1**} & \multicolumn{2}{c}{**Elements of Cluster 2**} & \multicolumn{2}{c}{**Elements of Cluster 3**} \\ \hline Po1 & Po2 14 dix17 & Po1 36 dix30 & Po4 \\ \hline Po2 & Po2 14 dix23 & Po2 14 dix21 & Po1 42 dix30 \\ \hline Po1 5 dix27 & Po2 15 dix23 & Po2 15 dix22 & Po2 15 dix17 \\ \hline Po1 5 dix30 & Po2 20 dix21 & Po2 20 dix17 & Po4 1 dix5 \\ \hline Po1 5 dix32 & Po2 20 dix23 & Po4 2 dix5 & Po4 1 dix18 \\ \hline Po1 26 dix27 & Po2 26 dix27 & Po4 3 dix5 & Po4 1 dix30 \\ \hline Po1 26 dix30 & Po4 2 dix1 & & Po4 2 dix17 \\ \hline Po1 26 dix32 & Po4 2 dix6 & & \\ \hline Po1 36 dix32 & Po4 3 dix7 & & \\ \hline Po1 42 dix27 & Po4 3 dix17 & & \\ \hline \end{tabular}
\end{table}
Table 7: Elements of individual clusters—toxic hyphal knob production, in the presence of _H. schachtii_ cysts, developed in time 5 h, 24 h, and 48 h.  
Figure 17: Analysis of cluster averages by K-means, considering toxic hyphal knob production, in the presence of _H. schachtii_ cysts, developed in 5 h, 24 h, and 48 h.  
Figure 19: Percent reduction/or increase in the _H. schachtii_ population by _P. ostreatus_ strains in the pot experiment, in which pots were sown with sugar beets and treated with mycelia, control was only sown by sugar beets; “+B” means variant with sugar beets.  
Figure 20: The influence of _P. ostreatus_ strains mycelium on the population of _H. schachtii_ in the pot experiment given in Pf/Pi coefficient; data followed by the same letter do not differ significantly (\(p\) = 0.05); Sb = sugar beet.  
The microplot experiment realized in the field, in breeding tents, resulted in a significant increase in the population of the beet cyst nematode (by 96.5%) in the variant of cultivation of sugar beet on a site not inoculated with oyster mushroom (Po4) mycelium. As a result of sugar beet cultivation on a site inhabited by _P. ostreatus_ Po4, a 16.9% reduction in the population of _H. schachtti_ was noted, thus achieving a similar phytosanitary effect as in the case of the control variant--black fallow without mycelium, in which a 16.9% decrease in the number of nematode eggs and larvae was achieved. Following the site inhabited with oyster mushroom mycelium resulted in a significant 45.4% decrease in the number of the tested pest, which was confirmed by the lowest Pf/Pi coefficient (Figures 21 and 22).