Preparation of sulfur nanoparticles in chitosan-copper complex and investigation of its nematicidal activity against Pratylenchus pratensis in vitro

Abstract

Sulfur nanoparticles (SNPs) in chitosan-copper (CS-Cu2+) complex solution were prepared by hydrolysis of sodium thiosulfate (Na2S2O3) in an acidic medium of CS-Cu2+ complex. The size of SNPs was inversely proportional to the Cu2+/−NH2 molar ratio, decreasing from 35 to 22 nm corresponding to the Cu2+/−NH2 molar ratio increasing from 0/1 to 1/1. The SNPs/CS-Cu2+ complex was characterized by Ultraviolet-Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectroscopy. The nematicidal activity against Pratylenchus pratensis in vitro was investigated by treating the CS-Cu2+ complex and SNPs/CS-Cu2+ complex with Cu2+/−NH2 molar ratio of 0.5/1. Results showed that the nematicidal activity of the SNPs/CS-Cu2+ complex was higher than that of the CS-Cu2+ complex, particularly the 50 % lethal dose (LC50) after 48 h of treatment was 77 and 89 mg/L, respectively. The results demonstrated that the prepared SNPs/CS-Cu2+ complex can be used as a nematicide for plants.