Present invention provides a method for controlling root knot nematodes (Meloidogyne javanica) comprising treating a plant for plant growth with silica nanoparticles wherein silica nanoparticles have suppressing action on nematodes. Silica nanoparticles are prepared by standard Stober method. Particle size obtained is 260 nm diameter with spherical morphology. The growth of three species of seedlings Solanum melongena (Bringal), Solanum lycopersicum (Tomato) and Capsicum annuum (Chilli) in nematode containing soil with 0.25%