Positive Chemotaxis of the Entomopathogenic Nematode (Panagrolaimorpha: Steinenematidae) towards High-Bush Blueberry () Root Volatiles.

The foraging behavior of the infective juveniles (IJs) of entomopathogenic nematodes (EPNs) relies on host-derived compounds, but in a tri-trophic context, herbivore-induced root volatiles act as signals enhancing the biological control of insect pests by recruiting EPNs. In southern Chile, the EPN exhibits the potential to control the raspberry weevil, a key pest of blueberry . However, there is no information on the quality of the blueberry root volatile plume or the response to these chemicals as putative attractants. Here, we describe the root volatile profile of blueberries and the chemotaxis behavior of towards the volatiles identified from roots, infested or uninfested with larvae. Among others, we found linalool, α-terpineol, limonene, eucalyptol, 2-carene, 1-nonine, 10-undecyn-1-ol, and methyl salicylate in root volatiles and, depending on the level of the emissions, they were selected for bioassays. In the dose-response tests, was attracted to all five tested concentrations of methyl salicylate, 1-nonine, α-terpineol, and 2-carene, as well as to 100 µg mL of 10-undecyn-1-ol, 0.1 and 100 µg mL of linalool, and 100 µg mL of limonene, whereas eucalyptol elicited no attraction or repellency. These results suggest that some volatiles released from damaged roots attract and may have implications for the biocontrol of subterranean pests.