Are synthetic VOC, typically emitted by barley (<i>Hordeum vulgare</i> L.) roots, navigation signals for entomopathogenic nematodes (<i>Steinernema</i> and <i>Heterorhabditis</i>)?
We tested the chemotactic response of infective juveniles (IJ) of the entomopathogenic nematodes (EPN) Heterorhabditis bacteriophora , Steinernema carpocapsae and S. feltiae to the synthetic volatile compounds (VOC) (dimethyl sulfide, hexanal, 2-pentylfuran, and (E)-non-2-enal) typically emitted by barley roots. For the purpose of our investigation, we used single VOC and their blends. We hypothesised that attraction behaviour exhibited by the EPN toward the tested VOC could be related to the species/strains and would vary with foraging strategy and VOC. Heterorhabditis bacteriophora was the most mobile species in our assay. We confirmed differences among commercial and soil-isolated strains of EPN. The movement of EPN toward different VOC was influenced by the species/strain of EPN. Our investigation showed synergistic effect of dimethyl sulfide as an attractant for EPN. The data showed that chemosensation is more a species/strain-specific trait than a host searching strategy. All compounds tested in our assay influenced the movement of IJ, suggesting that synthetic VOC, typically emitted by barley roots, could play an important role in EPN navigation.