Neonicotinoid uptake by maize plants emerged from coated seeds and by two common weeds grown in close proximity to coated seeds has been studied. Uptake of thiamethoxam (TMX) and clothianidin (CLO) have been characterized via guttation liquid measurements. The creeping thistle (Cirsium arvense), a well-known maize weed, as well as red poppy or Flanders poppy (Papaver rhoeas) were chosen as model species. The results confirmed that cross-contamination may occur by uptake of the neonicotinoid AIs through soil from neighbouring plants that emerged from coated seeds. Although the levels of these neonicotinoids were substantially lower in the guttation liquid of the weeds than in that of maize plants emerged from coated seeds, the compounds were detected up to 36th day after planting of the maize seeds. The highest peak concentrations of TMX were around 150 and 21mgL(-1), while similar data for CLO were around 70 and 21mgL(-1) for maize and creeping thistle, respectively. Mostly due to its higher guttation intensity significantly lower values were determined for red poppy (0.740mgL(-1)).
Mörtl M., Darvas B. et al
Mörtl, M. Darvas, B. Vehovszky, Á. Győri, J. Székács, A.
Contamination of the guttation liquid of two common weeds with neonicotinoids from coated maize seeds planted in close proximity
Science of The Total Environment, 649: 1137-1143
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