Species-Specific Chemotactic Responses of Entomopathogenic and Slug-Parasitic Nematodes to Cannabinoids from Cannabis sativa L.

The increasing environmental and health concerns associated with synthetic pesticides underscore the need for sustainable alternatives in pest management. This study investigates the chemotactic responses of five nematode species—Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, Phasmarhabditis papillosa, and Oscheius myriophilus—to three major cannabinoids from Cannabis sativa: Δ9-tetrahydrocannabinol (THC), cannabigerol (CBG), and cannabidiol (CBD). Using a standardized chemotaxis assay, we quantified infective juvenile movement and calculated Chemotaxis Index (CI) values across varying cannabinoid concentrations. Our results revealed strong species-specific and dose-dependent responses. THC and CBG elicited significant attractant effects in P. papillosa, S. feltiae, and H. bacteriophora, with CI values ≥ 0.2, indicating their potential as behavioral modulators. In contrast, CBD had weaker or repellent effects, particularly at higher concentrations. O. myriophilus exhibited no consistent response, underscoring species-specific variation in chemosensory sensitivity. These findings demonstrate the potential utility of cannabinoids, especially THC and CBG, as biocompatible cues to enhance the efficacy of nematode-based biological control agents in integrated pest management (IPM). Further field-based studies are recommended to validate these results under realistic agricultural conditions.