Toxicity of silver, titanium and silicon nanoparticles on the root-knot nematode, Meloidogyne incognita, and growth parameters of tomato

Abstract

The toxicity of three nanoparticles, silver (AgNP, 20 nm), silicon oxide (SiO2NP, 11-14 nm) and titanium oxide (TiO2NP, 20 nm), to the root-knot nematode, Meloidogyne incognita, was studied in laboratory and pot experiments. Application rates of all nanoparticles were 1.5, 3, 6, 12.5, 25, 50, 100, 200, 400 and 800 mg nanoparticles (ml water)−1 for laboratory experiment to determine their effects on motility and mortality of second-stage juveniles (J2). In pot experiment, 0.02, 0.01, 0.005, 0.0025, 0.00125 and 0.0007% (w/w) of nano-silver and nano-titanium were applied to examine effects on nematode activity and plant growth components of tomato (Solanum lycopersicum). Results showed 100% J2 immobility and mortality in treatments of 800, 400 and 200 mg ml−1 of AgNP; the LC50 for AgNP was 100 mg ml−1. J2 mortality was 48, 16 and 7.3% in 100, 50 and 25 mg ml−1 of AgNP, respectively. J2 mortality was 4.3 and 2% in 800 and 400 mg ml−1 of TiO2NP, respectively. No J2 mortality was seen in all other treatments after 24 h exposure. In a pot experiment, all treatments of AgNP and 0.02% TiO2NP completely controlled M. incognita. Treatments of 0.02, 0.01 and 0.005% of AgNP as well as 0.02% of TiO2NP were toxic to tomato plants and significantly reduced tomato root and stem length and fresh weights in comparison to control.