>We have shown that chronic dietary exposure to a

> fungicide, pesticide mixtures, and a formulation solvent have the potential
> to impact honey bee populations, and warrants further investigation.
>

I'm freshly returned from the American Bee Research Conference, where I was
able to discuss points in experimental design with various researchers.
One problem is that one should not assume that the level of pesticide in
beebread winds up being the level to which larvae are actually exposed.
The data that I've seen indicate that for the few pesticides for which
tests have actually been run, that the nurse bees produce jelly that
contains a greatly reduced concentration of the pesticide (the nurses
consume beebread, digest it, and then produce purified jelly) .  That may
not be the case for the pesticides tested in this paper, but without
validation, the benefit of the doubt should go to reduced pesticide
concentration in the jelly.

That is not to say that a reduced concentration cannot exhibit toxic
effects.  In the case of the IGR dimilin, apparently even the greatly
reduced amount in jelly can cause toxicity.

Larvae are typically fed little actual pollen.  At the conference, I
suggested a protocol for measuring to what extent larvae in almond
pollination are fed actual pollen grains under natural conditions,
hopefully to be used to validate a very expensive study that is being
partially funded by two groups for which I am a scientific advisor.

I applaud the work of the Frazier lab, and will sorely miss Dr. Jim Frazier
when he retires in June.  However, Dr. Maryann Frazier plans to carry on
with her other excellent Penn State collaborators.

Jim Fischer's points are well taken.  Although it may be of benefit in
initial exploratory studies to test products at high rates,
field-applicable studies should be done at field-realistic doses.
Researchers at various labs are starting to pay serious attention to
fungicides and surfactants (especially since they are so heavily applied to
almonds), and we can expect to learn more about their effects upon bees in
the near future.


-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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