We tested the chemotaxic response of infective juveniles (IJs) of the entomopathogenic nematodes (EPNs) Heterorhbaditis bacteriophora, Steinernema carpocapsae, and S. feltiae to the synthetic volatile compounds (VOCs) (dimethyl sulfide, hexanal, 2-pentylfuran, and (E)–non-2-enal) typically emitted by damaged barley roots. For the purpose of our investigation we used single VOCs and their blends. We hypothesized that attraction behavior exhibited by the EPNs toward the tested VOCs could be related to the species/strains and would vary with foraging strategy and VOCs. H. bacteriophora was the most mobile species in our assay. We confirmed differences among commercial and soil isolated strains of EPNs. The movement of EPNs toward different VOCs was influenced by the species/strain of EPNs. Our investigation showed synergistic effect of dimethyl sulfide as an attractant for EPNs. 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 IJs, suggesting that synthetic VOCs, typically emitted by barley roots could play an important role in EPNs navigation.
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