The essential oil (EO) and hydrosol (HL) isolated from Cuminum cyminum (cumin) seeds were evaluated against the root-knot nematodes Meloidogyne incognita and M. javanica. The efficacy of extracts on the motility, hatching, and survival in soil of second-stage juveniles (J2s), and the activity on egg differentiation were tested. All J2s were paralyzed after immersion in the EO at 62.5 μL/L concentration for 96 h. Encouraging results were recorded using HL equal to or higher than 10% concentration for both Meloidogyne species tested. More than 70% paralyzed J2s were recorded after immersion for 48 h, while the percentage was increased to higher than 90% after 96 h of immersion. A clear effect on egg differentiation was observed after immersion in EO or HL. A significant decrease in egg differentiation was revealed at even low concentrations of EO while an evident decrease in egg differentiation was recorded after immersion of eggs in 50% HL dilution. Decreased hatching of M. incognita and M. javanica J2s was observed with the increase in concentration. The lowest numbers of hatched J2s were recorded when EO was used at 1000 and 2000 μL/L concentrations. A constant reduction in root-knot nematode J2 hatching was observed upon increasing the concentration of HL from 5% to 50%. The EO of C. cyminum is characterized by the presence of γ-terpinene-7-al (34.95%), cumin aldehydes (26.48), and α-terpinene-7-al (12.77%). The above constituents were observed in HL following the same order as that observed in EO. The components γ-terpinene (11.09%) and ο-cymene (6.56%) were also recorded in EO while they were absent in HL.
Keywords: bio-pesticides; nematicidal activity; plant parasitic nematodes control; root-knot nematode management.