Comparison of Biological Activity of Field Isolates of Steinernema feltiae with a Commercial S. feltiae Biopesticide Product

SIMPLE SUMMARY: Entomopathogenic nematodes (Steinernematidae) are obligate insect parasites and are used for insect pest control, particularly on amenity grassland and in horticulture. Extensive surveys have been conducted across the globe to isolate locally adapted entomopathogenic nematodes species. The biological activity and morphology of three new isolates of Steinernema feltiae from Poland are described. New S. feltiae isolates from Poland showed close genetic similarity to other isolates of this species and exhibited a high reproductive rate and invasive capacity compared to the commercial biopesticide. ABSTRACT: Insect trap studies were carried out to determine the presence of entomopathogenic nematodes (EPN) from the family Steinernematidae in the soils of Poland and to compare the biological activities of field nematode isolates with nematodes from commercial biopesticide. The fauna of these organisms in central Poland is poorly studied in both taxonomic and biological terms. Tilled soils representative of this region were sampled from cultivated fields. EPN were isolated from soil samples under laboratory conditions and identified using a key for species identification and molecular analysis. Basic morphometric parameters of infective juveniles and adult males of the first generation were determined. The research showed that males and infective juveniles Steinernema feltiae from Łoniów were the largest. The smallest infective juveniles were found in the isolate from Oblasy, and the smallest males in the isolate from Danków. In Poland, new field isolates showed close genetic similarity to other S. feltiae isolates. The research showed that the field isolates from Poland had greater infectivity and rate of reproduction compared with nematodes from the commercial biopesticide. The findings indicate the potential use of field S. feltiae isolates from Poland (iso1Lon, iso1Dan and iso1Obl) to develop new biopesticide products.