Determination of the Absorption, Translocation, and Distribution of Imidacloprid in Wheat

Neonicotinoids, a class of insecticides, are widely used because of their novel modes of action, high insecticidal activity, and strong root uptake. Imidacloprid, the most widely used insecticide worldwide, is a representative first-generation neonicotinoid and is used in pest control for crops, vegetables, and fruit trees. With such a broad application of imidacloprid, its residue in crops has attracted increasing scrutiny. In the present study, 15 wheat seedlings were placed in a culture medium containing 0.5 mg/L or 5 mg/L imidacloprid for hydroculture. The content of imidacloprid in the wheat roots and leaves was determined after 1 day, 2 days, and 3 days of hydroculture to explore the migration and distribution of imidacloprid in wheat. The results showed that imidacloprid was detected both in the roots and leaves of the wheat plant, and the content of imidacloprid in the roots was higher than that in the leaves. Furthermore, the imidacloprid concentration in the wheat increased with increasing exposure time. After 3 days of exposure, the roots and leaves of the wheat in the 0.5 mg/L treatment group contained 4.55 mg/kg ± 1.45 mg/kg and 1.30 mg/kg ± 0.08 mg/kg imidacloprid, respectively, while the roots and leaves of the 5 mg/L treatment group contained 42.5 mg/kg ± 0.62 mg/kg and 8.71 mg/kg ± 0.14 mg/kg imidacloprid, respectively. The results from the present study allow for a better understanding of pesticide residues in crops and provide a data reference for the environmental risk assessment of pesticides.