The purpose of this study was to test the nematicidal activity of extracts of two marine algae (Colpomenia sinuosa and Corallina mediterranea) and their synthesized silver nanoparticles against root-knot nematodes (Meloidogyne incognita) that infest tomato plants. Scanning electron microscopy (SEM) revealed that nanoparticles had aggregated into anisotropic Ag particles, and transmission electron microscopy (TEM) revealed that the particle sizes were less than 40 nm. Fourier Transform Infrared Spectroscopy (FT-IR) analysis revealed that the obtained nanoparticles had a sharp absorbance between 440 and 4000 cm−1, with 13 distinct peaks ranging from 474 to 3915 cm−1. Methylene chloride extracts and nanoparticles synthesized from both algae species were used to treat M. incognita. C. sinuosa nanoparticles had the highest nematicidal activity of any treatment. Furthermore, and in contrast to other treatments, C. sinuosa nanoparticles reduced the number of nematode galls, egg-masses per root, and eggs/egg mass, while also improving plant growth parameters. C. sinuosa's methylene chloride extract was more active than C. mediterranea's, and the most effective eluent of this solvent was hexane: methylene chloride: ethyl acetate (1: 0.5: 0.5, v/v/v). When applied to M. incognita, the third fraction of this eluent was the most effective, resulting in 87.5% mortality after 12 h and 100% mortality after 24 and 72 h of exposure. The presence of seven bioactive constituents was discovered during the analysis of this fraction. In conclusion, the silver nanoparticles synthesized from C. sinuosa could be used as alternative chemical nematicides.

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This study aimed to evaluate the nematicidal activity of two marine algae (Colpomenia sinuosa and Corallina mediterranea) extracts and their synthesized silver nanoparticles against the root-knot nematode (Meloidogyne incognita) infecting tomato plant. Scanning Electron Microscope (SEM) showed that the obtained nanoparticles were aggregated in anisotropic Ag particles. Transmission Electron Microscope (TEM), results showed the particles size was less than 40 nm. Whenever, FT-IR analysis spectrum presented sharp absorbance between 440 and 4000 cm-1 for the obtained nanoparticles, with 13 distinct peaks ranged from 3915 − 474.Both of methylene chloride extract and its synthesized green silver nanoparticles were applied against the M. incognita. The results indicated that the synthesized silver nanoparticles of C. sinuosa exhibited the highest nematicidal activity. Besides, they reduced number of nematode galls, number of egg-masses per root and eggs/egg mass, as well as growth parameters of the treated plants with nanoparticles were enhanced comparing with the other treatments. While the methylene chloride extract of C. sinuosa exhibited higher activity than that of C. mediterranea, and the most effective eleuent of this solvent was Hexane: methylene chloride: ethyl acetate (1: 0.5: 0.5, v/v/v). The 3rd fraction of this eluent was the most effective one when it was applied on M. incognita, resulting in 87.5 % mortality after 12 h and 100 % after 24 and 72 h of exposure. The analysis of this fraction revealed the presence of seven bioactive constituents. Conclusively, the synthesized silver nanoparticles of C. sinuosa could be considered as alternative chemical nematicides.