> For one thing, I do not see chlorothalonil in the list of fungicides, and
I am not sure what metabolite might relate to

> it.


This surprised me too, Stan!

>But for imidacloprid the  LD50 is 4 - 71 ng per bee and the average
> detection in the positives was 30.8 ppb.
>

That high figure is of concern to me too!  It would suggest that the
exposure was due to something other than seed-treated crops--I suspect
perhaps a foliar application.  This should clearly be followed up.

>
> >So it is clear that that neonicotinoid (it would now likely
> be clothianidin) was the major field insecticide found in the
> beehives surveyed in killing amounts.


Now you may be starting to stretch a bit far.  In the first place, there
were zero detections of clothianidin or its metabolites (I checked with the
author of the survey).  I've discussed this data in my latest article.

>
> >Really you have to
> compare how bees do on untreated canola to how they do on treated canola
> and I would like to see that experiment done on large acreage rather than
> the little sample fields that the new Scott-Dupree experiment


The number of hives in those fields (which I visited) would suggest that
the bees in those hives would be foraging nearly exclusively upon the test
fields.  Pollen analysis will verify.  I feel that you are being premature
in discounting the study.
-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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