> Going back to the Iwasa paper, recall this piece 
> of the quoted text:
> "especially the DMI-fungicides (triflumizole,
> propiconazole, triadimefon and epoxiconazole)
> had a much greater effect on acetamiprid toxicity than
> either DEF or DEM..."

I remember that paper.  If read to the end, it also says:

"However,in cage studies where acetamiprid and triflumizole were applied in
combination to alfalfa at the maximum recommended rate, no bee mortality was
detected, suggesting that certainly acetamiprid alone and even acetamiprid
in combination with a potent P450 inhibitor, is safe to honey bees."

For the two pesticides that can interact with the fungicides (acetamiprid
and thiacloprid), the result of making them "a thousand times more toxic"
would make these pesticides only between one 10th and one 100th as toxic as
most of the pesticides "of concern" to beekeepers, such as Imidacloprid. 

The paper that found the increase in toxicity for these pesticides made it
very clear that the interaction that they saw had no impact on bees:

"These results suggest that despite the high synergism ratios observed in
the laboratory between acetamiprid and trflumizole, no practical adverse
effect occurs against the honey bee when exposed to treated plants at the
maximum recommended treatment levels. More studies will be needed in the
future in order to further validate this conclusion. Schmuck et al. (2003)
also found at recommended use rates that thiacloprid poses a negligible
lethal risk to honey bees when applied either alone or in tank mixes with
fungicides from different chemical classes."

So, they were able to get a reaction when painting it directly on bees using
a methanol carrier, but the methanol itself has been realized as a nasty
thing to use on bees when the bee is soaked in it.

Back in 2006-2007, there was so much worry, Bayer put this in an "FAQ"
document:
The Bayer FAQ said:

"Is the toxicity of neonicotinoid insecticides increased when they are mixed
with fungicides?

The toxicity of the nitroguanidine compounds (imidacloprid, thiamethoxam,
clothianidin, and dinotefuran) which are the ones that are highly toxic to
honey bees, is NOT increased when they are mixed with certain fungicides.
There is some interesting research that showed that certain azole fungicides
synergize the toxicity of the cyanoamidine subclass of neonicotinoid
compounds (acetamiprid and thiacloprid). These compounds are relatively
non-toxic to honey bees because the bees have enzymes that break them down
quickly to non-toxic byproducts. However, the presence of azole fungicides
blocks the activity of these detoxifying enzymes. The
result is these compounds become much more toxic (but not more toxic than
nitroguanidines) when the bee has also been exposed to the fungicide. This
synergistic effect has only been demonstrated to occur under highly
artificial laboratory conditions. In field trials in which azole fungicides
and cyanoamidine compounds were mixed and applied, there was no evidence of
synergistic toxicity to honeybees."

And they cited these two papers:

Iwasa T., Motoyama,N., Ambrose,J.T., Roe, R.M. (2004): Mechanism for the
differential toxicity of
neonicotinoid insecticides in the honey bee, Apis mellifera. Crop Protection
23 (2004) 371-378.

Schmuck, R., Nauen, R., Ebbinghaus-Kintscher, U. (2003): Effects of
imidacloprid and common plant
metabolites of imidacloprid in the honeybee: toxicological and biochemical
considerations, Bulletin of
Insectology 56 (1): 27-34.

My wife just walked by looked at my screen, and reminded me I must defer to
her on these "which pesticide is which" questions. She was channeling
Gilbert and Sullivan again, as I reported she did last opera season... found
it,- here's the link:

http://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A2=ind1501&L=BEE-L&
P=R83&1=BEE-L&9=A&J=on&X=D212A2BBFF2E8301AA
http://tinyurl.com/ohs9lmw

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