Comparison of Translocation, Distribution, Metabolism, and the Health Risk of Cyetpyrafen in Strawberry–Soil Systems under Foliar Spray and Root Irrigation Treatments

Selection of the appropriate application method is critical for ensuring pesticide efficacy and food/environment safety. This study systematically compared the fate and health risks of cyetpyrafen in strawberry-soil systems under foliar spray and root irrigation. Foliar spray resulted in a limited downward translocation of cyetpyrafen with translocation factors (TFroot/leaf) of 0.002-0.006. In contrast, root irrigation led to its preferential accumulation in roots with root concentration factors up to 3.11 and limited upward translocation (TFleaf/root: 0.01-0.13). Photoisomerization to E-cyetpyrafen (18.9-32.5%) was the dominant transformation pathway in strawberry plants under foliar spray, whereas cyetpyrafen was mainly hydrolyzed to M-309 (7.7-22.5%) in roots under root irrigation. Although its dietary risks for humans were acceptable (the maximum risk quotient: 7.29 × 10⁻⁷) for both methods, M-309 in roots (up to 497.8 μg kg⁻¹) and soil (45.0 μg kg⁻¹) under root irrigation posed potential risks to nontarget organisms.