Population structure of free-living and plant-parasitic nematodes in strawberry plantations under organic farming conditions

Organic production of strawberry (Fragaria × ananassa Duch.) is increasing world-wide, but knowledge about the influence of cultural practices on the beneficial and harmful fauna is empirical rather than field-based. Some species of plant-parasitic nematodes, which are closely related to the host plants, damage strawberry plants. They can occur in populations with joint free-living soil nematodes. The purpose of this work was to study the soil nematode communities and to determine the ratio between free-living soil and plant-parasitic nematodes in organic strawberry production systems. The investigation of the nematode populations was carried out in the region of the Balkan Mountain Range, village Sredogriv during the vegetation period on the area of 10 ha, with cultivar 'Senga Sengana'. The following genera of plant-parasitic nematodes were identified: Pratylenchus, Tylenchorhynchus, Hoplolaimus, Helicotylenchus. In free-living genera, the fungivore nematodes Aphelenchoides, Filenchus and Aphelenchus were dominated, followed by the bacteriovore genera Rhabditis and Cephalobus. The established indicators of the nematode communities (maturity index and plant parasite index) can be used as bioindicators for the health status of the plantation.