Research on new pesticides based on plant extracts, aimed at the development of nontoxic formulates, has recently gained increased interest. This study investigated the use of the volatilome of rucola (Eruca sativa) as a powerful natural nematicidal agent against the root-knot nematode, Meloidogyne incognita. Analysis of the composition of the volatilome, using GC-MS-SPME, showed that the compound (Z)-3-hexenyl acetate was the most abundant, followed by (Z)-3-hexen-1-ol and erucin, with relative percentages of 22.7 ± 1.6, 15.9 ± 2.3, and 8.6 ± 1.3, respectively. Testing of the nematicidal activity of rucola volatile compounds revealed that erucin, pentyl isothiocyanate, hexyl isothiocyanate, (E)-2-hexenal, 2-ethylfuran, and methyl thiocyanate were the most active with EC50 values of 3.2 ± 1.7, 11.1 ± 5.0, 11.3 ± 2.6, 15.0 ± 3.3, 16.0 ± 5.0, and 18.1 ± 0.6 mg/L, respectively, after 24 h of incubation. Moreover, the nematicidal activity of fresh rucola used as soil amendant in a containerized culture of tomato decreased the nematode infection in a dose-response manner (EC50 = 20.03 mg/g) and plant growth was improved. On the basis of these results, E. sativa can be considered as a promising companion plant in intercropping strategies for tomato growers to control root-knot nematodes.

Parsley exhibits promising nematicidal activity as an organic amendment and as a source of nematotoxic furanocoumarins.

Recent research has been focused on the potential of plant natural products for the control of nematodes, but few studies are reported on synergistic interactions and egg hatch inhibition properties of botanicals. Herein, we evaluate the nematicidal activity of (E,E)-2,4-decadienal, 2-undecanone, furfural and (E)-2-decenal alone and in binary mixtures, on different Meloidogyne spp. and growth stages. (E,E)-2,4-decadienal exhibited strong paralysis activity on second-stage M. incognita,M. javanica and M. arenaria juveniles (EC50/4d = 8.06, 9.04 and 12.90 μg mL−1, respectively) and all its binary mixtures demonstrated synergy on all nematode species. (E,E)-2,4-decadienal best inhibited M. incognita undifferentiated egg hatch and J2 release from eggs immersed in 10 μg mL−1 solution. SEM experiments revealed malformations, in the form of constrictions, along the larvae body retained in eggs treated with (E)-2-decenal. Egg masses treated with 1 μg mL−1 solution of (E)-2-decenal released less than 50 % of the eggs if compared with the control. (E)-2-decenal and (E,E)-2,4-decadienal arrested M. incognita life cycle in pot bioassays (EC50 = 77.46 and 114.47 mg kg−1), with the latter additionally promoting tomato growth. Ailanthus altissima powder (AWP) and water extract (AWE), naturally containing (E,E)-2,4-decadienal and (E)-2-decenal, strongly arrested M. incognita life cycle in tomato plants, and AWP was far more active than AWE. Thus, we conclude that (E,E)-2,4-decadienal and (E)-2-decenal are promising nematicidal agents used alone, in artificial blends or as naturally present in botanical soil amendments

The use of natural compounds to control phytonematodes is significantly increasing, as most of the old synthetic pesticides have been banned due to their eco-hostile character. Plant secondary metabolites are now evaluated as biologically active molecules against Meloidogyne spp. but their target site in the nematode body is rarely specified. Herein, we report on the ultrastructure modifications of the Meloidogyne incognita J2 after treatment with nematicidal plant secondary metabolites, that is acetic acid, (E )-2-decenal, and 2-undecanone. The commercial nematicide fosthiazate acting on acetylcholinesterase was used as control. For this reason, scanning electron microscopy and transmission electron microscopy have been employed. The acetic acid mainly harmed the cuticle, degenerated the nuclei of pseudocoel cells, and vacuolised the cytoplasm. The (E )-2-decenal and 2-undecanone did neither harm to the cuticle nor the somatic muscles but they degenerated the pseudocoel cells. (E )-2-decenal caused malformation of somatic muscles. According to the above, the nematicidal compounds seem to enter the nematode body principally via the digestive system rather than the cuticle, since the main part of the damage is internal.

We investigated Solanum nigrum (seeds) and Datura stramonium (shoots) against root-knot nematodes in terms of J2 paralysis and egg hatch inhibition (methanol extract), as well as inhibition of nematode development in host roots (soil amending with either S. nigrum seeds' or D. stramonium shoots' meal). Datura stramonium was found equally effective at inhibiting motility of Meloidogyne incognita and Meloidogyne javanica (both EC 50 = 427 μ g mL-1 at 3 day), but inhibition occurred more quickly for M. incognita (1 day). Solanum nigrum was faster and more effective at inhibiting motility of M. incognita than M. javanica (EC 50 = 481 and 954 μ g mL-1 at 3 day, respectively). Datura stramonium was slower, but eventually more potent in decreasing egg hatch and cell division in M. incognita eggs, than S. nigrum. Specifically, D. stramonium significantly inhibited cell division in eggs immersed in at least 100 and 1 μ g mL-1 at Day 6 and 10, respectively. Solanum nigrum impeded cell division in un-differentiated eggs immersed in not less than 10 and 100 μ g mL-1 after days 2 and 6, respectively. Both extracts were similar in suppressing J2 exclosure but D. stramonium was effective in smaller test concentrations. Specifically, D. stramonium suppressed J2 emerging from eggs immersed in 10 μ g mL-1 at day2, and in at least 1 μ g mL-1 at day 6. Solanum nigrum significantly reduced J2 hatch from eggs immersed in a minimum of 100 μ g mL-1 at day 2 and not less than 1,000 μ g mL-1 at day 6. In pots, powdered S. nigrum seeds meal was more active than D. stramonium and the respective EC 50 females/g values for M. incognita were 1.13 and 11.4 mg g-1 of soil, respectively. The chemical composition of active extracts was determined after derivatization by GC-MS. Chemical analysis of active extracts showed the presence of fatty acids with known nematicidal activity.