Hi Peter and All

> Has anyone analyzed canola honey and/or fed it to bees? Of course, bees overwinter on canola, but that doesn't seem to
> carry that much weight when these things are being discussed. 


Here is one study on residues in hive nectar and pollen documenting that low levels are detected and no effects on colonies noted.

G.
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Pohorecka K et al. 

Journal of Apicultural Science 115 Vol. 56 No. 2 2012
RESIDUES OF NEONICOTINOID INSECTICIDES IN BEE COLLECTED PLANT MATERIALS FROM OILSEED RAPE CROPS AND THEIR EFFECT ON BEE COLONIES

The risk exposure of bee colonies to the toxicity of systemic neonicotinoid insecticides
was assessed. Various methods of chemical prevention of commercial winter and spring
oilseed rape crops in field-realistic conditions were taken into account in the assessment.
Pesticides were applied in accordance with the actual agricultural practice. Commercial
crop protection products with thiamethoxam, clothianidin or imidacloprid were used as
seed treatment. Formulations containing acetamiprid or thiacloprid were used for spraying.
Fifteen healthy bee colonies were placed in close proximity to each of the oilseed rape fields
throughout the blooming period. During florescence, the samples of nectar (directly from
flowers and nectar flow from combs) and pollen loads were collected repeatedly. Samples
of honey, bee bread and adult bees were taken one week after the end of plants flowering.
To ensure high specificity and sensitivity of analysed pestcicides modified QuEChERS
extraction method and liquid chromatography coupled with tandem mass spectrometry
(LC-MS/MS) was used. The five of neonicotinoid insecticides (imidacloprid, clothianidin,
thiametoxam, acetamiprid and thiacloprid) were analyzed in multi-residue method with
0.1 - 10 ng/g limits of detection. Palynological analysis was done to determine the botanical
origin of the nectar, honey and pollen. Development of bee colonies (brood area, worker
biomass, colony health) was assessed every 3 weeks until the end of the beekeeping
season. The amount of pollen collected by bees per hive, bee bread area and rape honey
yield was also measured. The long-term effects of insecticides on bees were estimated
using the same methods in April of the following year.
All the neonicotinoid insecticides applied to control oilseed rape pests were present in
the samples of nectar and pollen. Their residue levels were lower than the acute oral and
contact LD 50 values. Among five examined neonicotinoids, the most frequently detected
were: thiamethoxam, thiacloprid and acetamiprid. These substances were present in
65, 64, and 51% of the nectar samples and in 37, 62, and 45% of the pollen samples,
respectively. The highest level of residues were noted after the thiamethoxam seed
treatment; on average, 4.2 and 3.8 ng/g in the nectar and pollen samples. In the nectar and
pollen samples from winter rape fields, lower levels of neonicotinoid residues were found
in comparison to spring rape samples. The contaminations of neonicotinoids applied as
seed dressing in nectar samples were significantly higher in comparison to the pollen 
samples. No negative effects of neonicotinoids on the bee mortality, brood development,
strength, and honey yield of healthy bee colonies were found throughout the study period.
However, the risk exposure of bee colonies on adverse impact of pesticide residues is high
in areas of intensively cultivated oilseed rape.


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