For cultivating crops, it is important to predict the biological half-lives of applied pesticides to ensure the safety of agricultural products. In this study a first order kinetic model was applied to investigate dissipation patterns of two triazole fungicides flusilazole and myclobutanil in apples. The biological half-lives and pre-harvest residue limits (PHRLs) for them in apples were established. At the harvest time, the residue amounts of two fungicides sprayed with single or triple doses were below their maximum residue limits (0.30 mg/kg for flusilazole and 0.50 mg/kg for myclobutanil) for apples established by Ministry of Food and Drug Safety of Korea. For flusilazole, in case of single dose, the equation was Ct = 0.0525e-0.112x and half- life was 6.7 days. In case of triple doses, the equation was Ct = 0.1059e-0.104x and half-life was 6.2 days. For myclobutanil, in case of single dose, the equation was Ct = 0.1087e-0.028x and half- life was 24.8 days. In case of triple doses, the equation was Ct = 0.234e-0.052x and half-life was 13.3 days. According to the established PHRLs, if the residue amounts of flusilazole and myclobutanil were 0.43 and 0.59 mg/kg, respectively, at 7 days prior to the harvest time, their residue amounts in the apples at the harvest time would be below the MRLs. Therefore, when pesticides were applied during the cultivation of apple, the biological half-lives need to be calculated with the optimal equation model.

Kinetic models of residue patterns of fungicides, flusilazole, and myclobutanil in apples

248th National Meeting (2014)

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