Background The root-knot nematode, Meloidogyne incognita, causes a high damage and yield decrease for many economic plants. The need for non-systemic effective new approaches and environmentally friendly methods for controlling the nematodes has directed research to some new and safe agrochemicals found in medicinal plants as new viable management options. Results In laboratory experiments, solidago and periwinkle aqueous and ethanolic extracts achieved high J2 mortality (%) concerning different dilutions; however, aqueous extracts were more effective for mortality than ethanolic extracts. Also, there was a direct relationship between the nematicidal activity of these extracts with both concentration and time of application. Inhibition of egg hatching by Periwinkle extracts was higher than that of solidago. Moreover, the nematicidal activity of tested extracts against J2 decreased significantly with prolonged storage time at + 5 °C, while did not with stored frozen at – 5 °C for 12 months. Periwinkle and solidago extracts killed the non-target organisms, i.e., rotifers and free-living nematodes. Seventy-five and 90% of total phytochemicals recovered from periwinkle and solidago, respectively were nematostatic or nematicidal to nematode viability, egg hatch in vitro, and development and reproduction in vivo despite the method of application (foliar and soil drench). The antagonistic effects of solidago were more pronounced in soil drench than periwinkle concerning their concentrations and methods of application. Conclusion Solidago and periwinkle plant extracts showed important sources of effective control phytochemicals against M. incognita.

In a survey study, 21 phytonematode genera, Aphelenchoides,

Reducing nematicide dose rates could be a useful strategy for mitigating their negative effects on health and the environment. In this study, enzymatic activities and the parasitic ability of Meloidogyne incognita after exposure to sub-lethal concentrations (0.25, 1, 2, and 5 ppm) of ethoprophos, fenamiphos, and oxamyl were investigated. Although the tested concentrations did not show nematicidal properties in vitro, they reduced root galls by at least 30% at 0.25 ppm and up to 67% at 5 ppm in pots, besides disrupting nematode fertility. For all three nematicides at 2 ppm, a chemotaxis assay showed that ≤ 11% of the nematode population was successfully oriented to the host roots, compared to 44% in the control. Ethoprophos and fenamiphos at 5 ppm showed poor inhibitory effects on acetylcholinesterase (AChE) activity (5.6% and 12.5%, respectively). In contrast, the same nematicides were shown to be strong ATPase inhibitors, causing 82.4% and 82.8% inhibition, respectively. At the same concentration, oxamyl moderately inhibited AChE and ATPase-specific activities, the inhibition being 22.5% and 35.2%, respectively. This study suggests that the use of very low nematicide concentrations could be a promising strategy for nematode management. Furthermore, it has also highlighted the role of ATPases as a possible target site for suppressing nematode activity in the development of future nematicides.

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