Hi Bill and All:

>Interesting reading, but I am hesitant to accept the conclusions of an
>organization dedicated to eliminating pesticides from the environment.
>Too much agenda.

I agree that the agenda is very obvious in the summary.  However, a few
facts on toxicity to aquatic invertebrates (mysids in particular) at
extremely low ppb were useful (and referenced).

>There is also an article in the latest Bee Culture by Mark Winston on
>the same subject and has more balance. Especially pointing the finger
>back at us for using organo-phosphates, which environmentally are a much
>more dangerous class of pesticides than imidacloprid.

I wonder why you say that organo-phospates are more environmentally
dangerous than imidacloprid.  At first I might have automatically agreed,
since I have always considered these the worst of the pesticides.  But now I
would ask you to consider the following facts and see whether you still
think that:

1.  In terms of toxicity there is almost nothing that can match the
lethality of imidacloprid.  Here are the LD 50 levels for bees for various
insecticides from my copy of Hive and Honeybee and the LD 50 (lethal dose
for 50 % of victims) for imidacloprid for bees agreed to by Bayer (3.7 to 40
nanograms per bee depending on which report you take).  For comparison
everything will be in micrograms (.000,001 g)

sevin       1.34
aldicarb     .285
DDT         5.14
lindane      .562
IMIDACLOPRID .004

I won't bother going through the list.  It will be sufficient to say that of
about 60 insecticides listed there is only one with a lower LD 50 than
imidacloprid, and that is "tepp" which is .001  However the book notes that
tepp has such a short residual activity that it only kills bees contacted at
treatment time or shortly thereafter.

2.  In terms of long term poisoning of the environment imidacloprid has to
be in a category right up there past all the competition!  A half life of
over a year is almost unheard of with past chemicals (excerpt for non
intentional pollutants like PCB's).  The study that Bayer commissioned on
PEI, done by Phillips Agritech showed a half life here of 366 to 457 days
and soil levels TWO years after application on potato ground were still 30
to 35 ppb.  The organo phosphates still in use today break down quickly. (I
realize that DDT didn't).

3.  In terms of breakdown products, imidacloprid is also not a benign
chemical.  The hydroxy metabolite is about as toxic as the parent compound,
and the olefine metabolite is MORE toxic. In the French studies the olefine
metabolite was toxic to bees at .00075 micrograms.  I know nothing about the
metabolites of organophosphate insecticides, so have no way to compare this.

I am not saying that you are wrong, Bill.  I am ignorant about what effects
these other insecticides have.  I have only studied up on imidacloprid out
of necessity.  But I wonder for what reason they would be considered worse
than this?  It seemed that they killed and then broke down.  At least
insects appeared to come back to the fields afterwards.  This stuff is like
the Eveready rabbit: it keeps killing and killing and killing....

Regards,
Stan
thinking: no hate mail from bunny lovers please