Nematicidal activity of different ecotypes of Helichrysum italicum (Roth) G. Don (Asterales: Asteraceae) against plant parasitic nematodes

This study was conducted in 2024 under laboratory conditions at the Department of Plant Protection, Faculty of Agriculture, Isparta University of Applied Sciences. The nematicidal effects of six concentrations of essential oils obtained from two ecotypes of Helichrysum italicum (Roth) G. Don (Asterales: Asteraceae) (France/Corsica, CF and Bosnia and Herzegovina, CBH) were evaluated against Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949 (Rhabditida: Meloidogynidae), Pratylenchus thornei (Sher & Allen, 1953) (Rhabditida: Pratylenchidae) and Ditylenchus dipsaci (Kühn, 1857) (Rhabditida: Anguinidae) at 25ºC. The CF ecotype had a higher essential oil yield (0.37%) than CBH (0.16%). Neryl acetate (55.89%) was the dominant component in CF oil, whereas ar-curcumene (20.09%) and α-pinene (17.91%) predominated in CBH oil. Essential oils from both ecotypes significantly increased nematode mortality compared with the control (p≤0.05). The highest mortality rates were obtained with CF oil at 1000 µg mL⁻¹ against D. dipsaci (91.2%) and P. thornei (82.8%). M. incognita was the least susceptible species. Results indicate that the CF ecotype possesses stronger nematicidal activity, likely due to its higher monoterpene and neryl acetate content. These findings suggest that H. italicum essential oil may serve as a promising natural nematicide candidate.