Biocontrol Potential of Pleurotus ostreatus Mycelium Against the Beet Cyst Nematode Heterodera schachtii for Breeding Purposes

Sugar beet (Beta vulgaris L.) is the world’s second most important source of sugar, yet its production is seriously threatened by the beet cyst nematode Heterodera schachtii. Managing this pest remains a major challenge, especially where the use of chemical nematicides is limited or prohibited, highlighting the need for sustainable biological alternatives. This study evaluated the edible fungus Pleurotus ostreatus as a potential biocontrol agent against H. schachtii. Several offspring strains derived from a wild parental isolate (Po4) were tested in both pot and field experiments. In pot trials, mycelial application to fallow soil reduced nematode populations by 46.9–71.3%, while in soils cultivated with sugar beet, reductions of 26.2–32.5% were observed. Field experiments conducted over two consecutive years confirmed the nematode-suppressive activity of the Po4 strain, with population decreases of approximately 45–48% in fallow soil and 7–21% in sugar beet plots, whereas control plots exhibited 2–3-fold increases. These consistent trends indicate that P. ostreatus mycelium effectively limits nematode proliferation under both controlled and field conditions. The findings demonstrate the potential of P. ostreatus as an environmentally sound and practical component of integrated pest management systems, offering sugar beet producers and breeding programs a novel biological approach to sustainable nematode control.