Guttation as an exposure route in the risk assessment for plant protection products – Review of the available data

The available data show that neither the detection of residues in guttation droplets nor the occurrence of guttation alone are sufficient to conclude an exposure (and hence a risk) for honey bees. While frequently observed in some crops (maize), guttation may be less likely occurring in others (sugar beets). Very low numbers of water foraging honey bees on guttation droplets indicate that this a minor route of exposure. The absence of effects concerning colony strength and mortality in the industry studies with systemic insecticides can be regarded as further evidence that the interactions of the different factors (plant uptake, occurrence of guttation, foraging behaviour) do not lead to any significant exposure of honey bee colonies.