Abstract :
Field experiments were conducted to investigate the persistence of diniconazole and etoxazole in broad bean pods, peels, seeds and soil. Samples were taken after zero, 1, 3, 5, 7, 9, 14 and 21 days after pesticides application. The diniconazole residue in plant samples was extracted by methanol, partition with dichloromethane, cleaned up using coagulation solution, while the soil samples were extracted with ethyl acetate. Estimation of diniconazole residues were performed by (GLC- ECD). Etoxazole was extracted from plant sampleswith acetone, and from soil samples using acetone: water (8: 2 v/v). The extract was partitioned with dichloromethane and cleaned-up througha florisil column.Determination of etoxazole residues were performed by HPLC-DAD. The recoveries of etoxazole and diniconazole were in the range between 81–99 %. The results indicated that the half–life values of diniconazole in pods, peels, seeds and soil were 2.46, 2.29, 5.25 and 5.56 days, respectively. While these values of etoxazole in pods, peels and soil were 2.27, 1.62 and 4.91 days, respectively. No residues of etoxazole could be detected in seeds. Diniconazole residue was below the MRL in seeds. The pre-harvest interval (PHI) of pods was in diniconazole application 9 days. And in case of etoxazole these were 11 days.
Keywords :
persistence , diniconazole , etoxazole , broad bean , PHI , GLC