Effects of Spraying Chitosan on Degradation of Chlorpyrifos and Dimethoate Residues in Spinach

Effects of spraying chitosan on chlorpyrifos and dimethoate residues in spinach was investigated in the openfield.Results showed that spraying different concentrations of chitosan(50,100,200,400mg·L-1)could reduce chlorpyrifos and dimethoate residues in spinach effectively.And among of the different concentrations of chitosan,low concentrations of chitosan could more effectively reduce chlorpyrifos and dimethoate residues in spinach.By spraying 50mg·L-1 of chitosan,chlorpyrifos residue in spinach was 40.2 percent lower than that of control,the plant pre-harvest interval(PHI)shorten 2.07d than that of control.While with 100mg·L-1 of chitosan,dimethoate residue in spinach was 46.9 percent lower and the PHI shorten 0.5d than that of control.The practice proved that chitosan as a degradation preparation of organophosphorus pesticide is feasible.