The ban imposed by the European Union on the use of neonicotinoids as sugar beet seed treatments was on the basis of the exposure of bees to residues of
neonicotinoids in pollen and nectar of succeeding crops. To address this concern, residues of thiamethoxam (TMX) and clothianidin (CTD) were analysed in soil
collected from fields planted in at least the previous year with thiamethoxam-treated sugar beet seed. This soil monitoring program was conducted at 94 sites across
Germany in two individual years. In addition, a succeeding crop study assessed residues in soil, in guttation fluid, pollen and nectar sampled from untreated
succeeding crops planted in the season after thiamethoxam seed-treated sugar beet at 8 field sites across 5 countries. The overall mean residues observed in soil monitoring
were 8.0 ± 0.5 µg TMX + CTD /kg in the season after use of treated sugar beet seed. Residue values decreased with increasing time interval between the latest
thiamethoxam or clothianidin application prior to the sugar beet drilling and with lower application frequency. Residues were detected in guttation fluid (2.0 - 37.7 µg
TMX/ L), however, risk to pollinators from this route of exposure are likely to be low based on the reported levels of consumption. Residues of thiamethoxam and
clothianidin in pollen and nectar sampled from the succeeding crops were detected at or below the LOQ (0.5-1 µg a.i./kg) in 86.7% of pollen and 98.6% of nectar samples
and, unlike guttation fluid residues, were not correlated with measured soil residues. Residues in pollen and nectar are lower than reported sublethal adverse effect
concentrations in studies with honeybee and bumble bee individuals and colonies fed only thiamethoxam treated sucrose and are lower than those reported to result in no
effects in honeybees, bumble bees and solitary bees foraging on seed-treated crops.