Soils represent the natural habitat of entomopathogenic nematodes (EPNs). When moving in soil, EPNs are oriented to follow a chemical signal (chemotaxis). Cannabis sativa L. is known to secrete a very wide spectrum of secondary metabolites. Ethanol extracts (EE) of different C. sativa L. organs were used to study the effect on EPN chemotaxis. The root, leaf and inflorescence EE of two hemp varieties and two medical cannabis breeding lines were used in laboratory chemotaxis assays with three EPN species (Steinernema carpocapsae, S. feltiae and Heterorhabditis bacteriophora) at 20 and 25 °C. The content of terpenes and cannabinoids in C. sativa L. inflorescences was measured as well. Overall, EPNs were most attracted or repelled by inflorescence extracts, followed by leaves and roots. The most abundant terpene in hemp inflorescences was trans caryophyllene (38.2% on average), the highest contents of total cannabidiol, total cannabigerol and total tetrahydrocannabinol were 9.65%, 0.89% and 0.62%, respectively. The attraction effect of S. sativa L. EE is a highly interesting outcome and could lead to the development of attractant compounds in EPN biological control. Cannabinoids and terpenes may be responsible for pronounced effects on EPN chemotaxis.
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