Preharvest fruit-drop is a challenge to bayberry production. 2,4-D sodium as a commonly used anti-fruit-drop hormone on bayberry can reduce the yield loss caused by preharvest fruit-drop. The persistence and risk assessment of 2,4-D sodium after applying on bayberries were investigated. A method for determining 2,4-D sodium in bayberry was established based on LC-MS-MS. The average recoveries of 2,4-D sodium were at the range of 93.7–95.8% with relative standard deviations (RSDs) ranging from 0.9 to 2.8%. The dissipation rates of 2,4-D sodium were described using first-order kinetics, and its half-life ranged from 11.2 to 13.8 days. A bayberry consumption survey was carried out for Chinese adults for the first time. The safety assessments of 2,4-D sodium were conducted by using field trail data as well as monitoring data. Results showed that the chronic risk quotient and the acute risk quotient were calculated to be 0.23–0.59 and 0.02–0.05%, respectively, for Chinese adults, indicating low dietary risk for adults and children. In the end, the household cleaning steps were compared, and results showed that water rinsing for 1 min can remove 49.9% 2,4-D sodium residue, which provides pesticide removal suggestion for consumers.
