Effects of sprayers and nozzles on spray drift and terminal residues of imidacloprid on wheat

Abstract

In pesticide application, it can be obtained by using appropriate nozzles and sprayers to reduce spray drift and pesticide residues. In this study, a field trail was conducted to determine the spray drift and pesticide residue of imidacloprid on wheat, using three types of flat fan nozzles from the LECHLER Company (LU120-02, AD120-02, IDK120-02) and two types of sprayers (guided-baffle shield sprayer (GBSS) and conventional sprayer (CS)). The spray drift (measured with both airborne and sediment samplers) and terminal residues on wheat were analyzed by liquid chromatography triple-quadrupole mass spectrometry. The results show that both the sediment drift and airborne spray profile were greatest for the LU120-02 nozzle, intermediate for the IDK120-02 nozzle, and lowest for the AD120-02 nozzle. The shielded sprayer gave one third of the drift recorded by airborne samplers and one half of the drift recorded by sediment samplers, compared with results from the CS. Airborne spray drift decreased with increasing height. The imidacloprid residues on wheat grain from different application methods were all below the maximum residue limit (MRL) suggested by EU (0.1 mg/kg) or China (0.05 mg/kg) and no imidacloprid residue was detected on wheat straw. Considering the factors on environment protection, food safety, and biological efficacy, the AD120-02 nozzle and GBSS performed better compared with other nozzles and sprayers. The combination of AD120-02 nozzle with a GBSS is likely to be the optimum application method on wheat.