Nematicidal Activity of Silver Nanoparticles Synthesized by Seaweeds Extracts Against Meloidogyne Incognita on Tomato Plant

Abstract 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.