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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.

Essential oil (EO) and hydrosol (HL) isolated from an indigenous plant species Satureja hellenica were evaluated against Meloidogyne incognita and M. javanica. Particularly, the activity of extracts on a second stage juvenile’s (J2s) motility, the hatching of J2s from eggs, egg differentiation and the effect on J2s in soil were tested. A paralysis of 100% of the J2s of both species was recorded after 96 h of immersion in the essential oil, at a dose of 2000 μL/L. At the same dose, the percentage of paralyzed J2s after 48 h of immersion was more than 80%, for both Meloidogyne species. The use of hydrosol has shown encouraging results only in the dilution of 50%, where for both Meloidogyne species tested, the percentage of paralyzed J2s was more than 70% after 48 h of immersion, while the percentage was increased to 90% after 96 h of immersion. Egg differentiation was ceased after immersion, either in EO or HL. However, this decrease in egg differentiation was evident only at higher concentrations of EO and at the highest HL dilution (0.5 v/v). The hatching of M. incognita J2s was decreasing as the dose was increasing. The lowest numbers of hatched J2s were recorded at the doses of 2000 and 4000 μL/L. A clear reduction in M. javanica J2s hatching was observed as the dose was increased to 250 μL/L, a fact constantly observed as the dose was increasing up to 4000 μL/L. Lower numbers of nematodes were recorded in roots grown in infested soil after the application of EO or HL at the highest doses. The EO of S. hellenica is characterized by the presence of p-cymene (27.46%) and carvacrol (23.25%), and in a lesser extent of other constituents, such as borneol (6.79%), carvacrol methylether (6.77%), γ-terpinene (4.63%) and 4-terpineol (3.65%). Carvacrol was the major constituent found in the HL (50.12%), followed by borneol and 4-terpineol (20.42 and 6.72%, respectively).

Fluazaindolizine is a novel sulfonamide nematicide that is the active ingredient (a.i.) of Salibro™, a.i. Reklemel™. Its compatibility with Pasteuria penetrans, a bacterial parasite of root-knot nematodes (Meloidogyne spp.), was investigated in populations of M. javanica and M. incognita. Spores of a single P. penetrans isolate (Pp 3) or a blend of six isolates were incubated in the suspensions of fluazaindolizine (Salibro TM 500SC, at 5, 50, and 250 ppm a.i.) and oxamyl (Vydate™ 10 L, 10% (a.i.) at 25 and 50 ppm a.i.) for 1, 7, and 21 days; controls were incubated in water. Thereafter, the suspensions were washed through a cellulose filter (3 µm) so as to remove the nematicide, and the spores retained on the filter were suspended in water. Juveniles (J2) were exposed in these spore suspensions in Petri dishes and the number of attached spores was recorded. Neither fluazaindolizine nor oxamyl, at all the tested dosages, had any negative effect on the rate of spore attachment. The spore encumbered J2 from some experiments were used to infect tomatoes. Females without egg masses were extracted from the roots after 50 days and checked for eggs in ovaries and mature spores of P. penetrans. Despite no mature spores present in the females, there was evidence of a low percentage of infection in a few treatments. A possible explanation is that since the bacterium had been kept stored in the form of dried roots for a long period, its ability to infect nematodes was decreased.

In the present study, combined interactions of the root‐knot nematode Meloidoyne javanica (M.j.) with the soil‐borne fungi Verticillium dahliae (V.d.), Fusarium oxysporum f.sp. radicis‐cucumerinum (F.o.r.c.) or Monosporascus cannonballus (M.c.) against susceptible plant hosts were evaluated. Direct and indirect interactions were tested by applying each pathogen (nematode or fungus) alone or together on the whole plant root system or on each of the two sides of a split‐root set‐up in all possible combinations. Plant–fungi–nematode interactions were estimated by measuring various disease and growth parameters on host plants. A significant increase of verticillium wilt symptoms was observed in eggplant when V.d. and M.j. were applied separately in split‐root plants compared with symptoms in whole root plants inoculated with both pathogens. Root and stem rot and root‐knot symptoms in cucumber were more severe when F.o.r.c. was combined with M.j. in a split‐root set‐up than when plants were only inoculated with a single pathogen on one part of the split‐root set‐up. No significant associations were observed in the case of melon‐M.c.‐M.j. interaction. Gene expression bioassays for cucumber‐F.o.r.c.‐M.j. interaction revealed increased transcriptomic activity for PAL1 gene in plants treated with F.o.r.c at 3 days postinoculation (d.p.i.), whereas high transcriptomic level for DEFENSIN gene was observed primarily in M.j.‐treated plants at 7 d.p.i. The possible interactions between the abovementioned pathosystems are presented and discussed for the first time in literature.