Study on the deposition, degradation and minimum effective dose of azoxystrobin in soybean

Azoxystrobin is an important fungicide to control soybean rust. It is an urgent task to clarify the residue characteristic of azoxystrobin in soybean. In this study, ultra performance liquid chromatography tandem mass spectrometry was used to establish a method for the determination of azoxystrobin residues in stems, leaves, pods and soil in soybean planting system. The limit of quantification (LOQ) was 0.005 mg/kg. The results of field experiments in Anhui, Shandong, and Jilin showed that azoxystrobin 250 g/L SC was mainly deposited in soybean leaves after application and the deposition concentration decreased gradually from north to south. The degradation rates were faster in the upper stems and leaves, and there was no significant difference between regions. The relationship between the control effect of azoxystrobin on soybean rust was compared under different doses, and the residues were provided. The minimum effective dose of azoxystrobin was 225 g a.i./hm². The research results of this paper are of great significance to guide the scientific application of azoxystrobin in soybean production and the practice of pesticide reduction on soybean.