> Out of all of the crops in Poland, oilseed rape (Brassica napus) is the most important and abundant forage source for honeybees. It is planted over an area of 950,000 hectares.
>
> The first purpose of our study was to measure the concentration of neonicotinoid insecticides (thiamethoxam, clothianidin, imidacloprid acetamiprid, and thiacloprid) in plant materials (nectar, pollen), and bee products (honey, bee bread). The second purpose was to assess the short- and long-term effect of these contaminants on bee colonies.
>
> In 2012, during the time when the colonies stayed in the rape fields, (from the 14th of June) and after transporting them to the stationary apiary (until the 30th of July) very low mortality was also noted.
>
> It can be concluded, that honey bees foraging on seed-treated and sprayed oilseed rape are exposed to clothianidin, imidacloprid, thiamethoxam, acetamiprid and thiacloprid residues in pollen, nectar, and honey. Even though the identified by us concentrations of insecticides were varied, they were below the concentrations which induce acute lethal effects.
>
> The results show that the residues of pesticides determined by us have not impaired the healthy honeybee colonies. However, the risk exposure of bee colonies to the adverse impacts of pesticide residues is high in areas of intensive oilseed rape cultivation.
>
> Short- and long-term side effects of the applied seed treatment and spraying of winter and spring oilseed rape on development and productivity of healthy bee colonies were not observed.
RESIDUES OF NEONICOTINOID INSECTICIDES IN BEE COLLECTED PLANT MATERIALS FROM OILSEED RAPE CROPS AND THEIR EFFECT ON BEE COLONIES
National Veterinary Research Institute, Department of Honey Bee Diseases, Puławy, Poland
Journal of Apicultural Science. Volume 56, Issue 2 January 2013
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