Persistence and Degradation Pattern of Acequinocyl and Its Metabolite, Hydroxyl-acequinocyl and Fenpyroximate in Butterburs (Petasites Japonicus Max.)

Abstract

Degradation patterns and persistence of acequinocyl and its metabolite, hydroxyl-acequinocyl (acequinocyl-OH), and fenpyroximate residues in butterburs (Petasites japonicus Max.), one of the minor crops in Republic of Korea, were investigated during cultivation. Butterburs were planted in two plots (plot A for double dose; plot B for single dose) in a greenhouse. Each pesticide was applied to the foliage of butterburs at hourly intervals. Recoveries of acequinocyl and acequinocyl-OH were 78.6%−84.7% ± relative standard deviation (RSD) 1.9%−4.8% and 83.7%−95.5% ± RSD 1.0%−3.6%, respectively. The total (Ʃ) of acequinocyl residues in butterburs disappeared by 96.0% at 14 days after the final application in plot A and by 75.9% at 7 days in plot B. The biological half-life of the total (Ʃ) acequinocyl and fenpyroximate was 3.0 days and 4.0 days respectively. These results were used for setting maximum residue levels and safe use standards for the pesticide during butterbur cultivation. The risk assessment showed that the maximum % acceptable daily intake was 4.71% for Ʃ acequinocyl and 8.81% for fenpyroximate. The theoretical maximum daily intake of Ʃ acequinocyl and fenpyroximate were 24.02% and 15.24%, respectively, indicating the concentrations of Ʃ acequinocyl and fenpyroximate in butterburs pose no health risks to Koreans.