Residue Dissipation Patterns of Indoxacarb and Pymetrozine in Broccoli under Greenhouse Conditions

Abstract

BACKGROUND: This study was carried out to establish pre-harvest residue limits (PHRLs) of indoxacarb and pymetrozine in broccoli under greenhouse conditions, based on dissipation patterns and biological half-lives of pesticides during 10 days after application. METHODS AND RESULTS: The field studies were conducted in two different greenhouse, located in Chungju-si (Field 1) and Gunsan-si (Field 2). Samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after spraying pesticide suspension. The analytical methods for indoxacarb and pymetrozine using HPLC-DAD were validated by recoveries ranging of 94.3-105.4% and 81.8-96.0%, respectively, and MLOQ (Method Limit of Quantification) of 0.05 mg/kg. Biological half-lives of indoxacarb and pymetrozine were 2.9 and 3.2-3.8 days in broccoli, respectively. The lower 95% confidence intervals of dissipation rate constant of indoxacarb were determined as 0.1508 (Field 1) and 0.2017 (Field 2), whereas those of pymetrozine were calculated as 0.1489 (Field 1) and 0.1577 (Field 2). CONCLUSION: The significant differences were not observed between the dissipation rates of indoxacarb and pymetrozine in broccoli. The major factor affecting residue dissipation was the dilution effect by fast growth. The PHRLs for 10 days prior to harvest were recommended as 30.06 (Field 1) and 18.07 (Field 2) mg/kg for indoxacarb, and 4.84 (Field 1) and 4.43 (Field 2) mg/kg for pymetrozine, respectively.

Risk Assessment of Azoxystrobin Residues in Fresh Crown Daisy from Farm to Fork

“…물이 출하되어 유통되는 것을 사전에 예방하고 있다 [6][7][8][9]. 현 재, 농산물에 설정된 농약의 PHRL(138종 농약, 1,241개 농 산물 품목)은 MRL과 비교하여 9.7% 수준으로 기준수가 낮 아서, 유통단계 농산물의 안전성 확보를 위하여 잔류농약 안 전성 검사에서 MRL을 초과하는 부적합 빈도가 높은 농산물 및 농약에 대한 PHRL 설정이 필요하다 [10].…”