> I suspect that the problem is related to the amount of seed dressing


> Overall, field studies show that neonicotinoid residues are extremely variable. 


These two statements I believe  show a slight misunderstanding of the seed coating and uptake.  The pesticide looses it effect over time.  Due to several factors as I understand it,  one  plant mass and disbursement,  and two degradation of the product.  Both of these can be effected by weather,  plant size and bloom date in relation to spray or seed coating.  I believe that why we see such variations in actual exposure.  Some of the things I have read  claim that by 45 days there are no detectable levels left.   Don't recall if that was the plant itself or pollen and nectar.   
Canola is perfect example in the plains.  Its planted in the fall, (winter varieties)  and by spring there is nothing left to slow down pest,  so many times a foaliar spray is applied just before bolt/bloom.



Charles

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