Degradation and distribution of imidaclopridin potatoes

The problem of translocation of the systemic pesticide imidacloprid in potato plants is addressed. The aim of the study was to investigate the pathways of movement, the dynamics of accumulation, and the degradation of the active substance in different plant parts. The field experiment was conducted in the Leningrad Region on the potato variety Udacha, with sampling of aboveground biomass from different parts of whole plants and tubers after treatment. Chemical analysis was performed using an in-house method based on the QuEChERS methodology with HPLC-UV detection. The results confirmed the predominantly xylem-mediated transport of imidacloprid, with maximum concentrations found in the upper foliage. A retrograde redistribution of the active substance downward along the foliage was observed 24 hours after treatment, which may be attributed to reverse flow in the xylem associated with nocturnal root pressure and guttation. Accumulation of imidacloprid residues in tubers was detected, with a peak concentration of 0.074 mg/kg on day 7, exceeding the established maximum residue limit (MRL) of 0.05 mg/kg. This finding suggests a possible downward (basipetal) transport, which is atypical for classic xylem-mobile compounds. The novelty of this study lies in the comprehensive experimental identification of the possible translocation pathways of imidacloprid and the assessment of its redistribution and degradation within the plant. The practical significance is demonstrated by the proven need for strict adherence to the pre-harvest interval for this pesticide on potatoes, as a temporary but significant exceedance of the MRL poses a potential toxicological risk.