Persistence and Dissipation Behavior of Selected Pesticide Residues in Grape Berries and Leaves under Field Conditions in Egypt

Pesticide use boosts agricultural productivity, but excessive residues can harm human health. To ensure consumer safety, pesticide residue levels must remain below the established Maximum Residue Limits (MRLs). Therefore, regular monitoring of pesticide residues in fruits is essential for maintaining food safety and public health. In this study, the dissipation rate, half-life (t₀.₅), and pre-harvest interval (PHI) of three commonly used pesticides in grape cultivation, boscalid, penconazole, and dimethomorph, were investigated in grape berries and leaves under field conditions. Residue levels were measured at various time intervals as following: 0 (2 hours), 1, 3, 5, 7, 10, 14, and 21 days post-application. These pesticides were applied to grapevines under open-field conditions.. Sample extraction and cleanup were conducted using the QuEChERS method, followed by analysis through High-Performance Liquid Chromatography (HPLC) coupled with a QTRAP mass spectrometer. The results indicated that the half-lives of boscalid, penconazole, and dimethomorph in grape fruits and leaves were 7.0 and 1.24 days, 5.0 and 6.7 days, and 2.49 and 3.5 days, respectively. Corresponding pre-harvest intervals (PHIs) were 5.0 and 3.0 days for boscalid, 4.0 and 6.0 days for penconazole, and 8.5 and 4.5 days for dimethomorph. Additionally, the estimated degradation rates in grape berries and leaves were as follows: boscalid (0.0991 and 0.1036), penconazole (0.557 and 0.279), and dimethomorph (0.147 and 0.0200), respectively. Rapid degradation (half-lives ≤7 days) and PHIs ≤8.5 days suggest low persistence of these pesticides, aligning with food safety standards and minimizing consumer exposure risks.