On Wed, Mar 27, 2013 at 3:04 AM, Stellio Matson <[log in to unmask]>wrote:

>
> On page 14 of this EPA Environmental Risk Assessment for clothianidin
> it says: http://www.scribd.com/doc/46041897/Clothianidin
>

I was reading the document (I will reply to earthworm later, I need to go
out) and I noticed that on pages 18, 19 and 20 it gives the clothianidin
application rates (FOR SEED TREATMENT).  We have not discussed them before
and in our little spread sheet exercise we just used a 1 which was fine for
that exercise.  But then we keep getting posts about no harm to bees from
corn pollen, and no harm to bees on canola (and I keep bees on thiamethoxam
treated canola).  I think for the danger to bees from soil residue we are
looking at the wrong crops.  Please look at the figures below from the
document above.  The range of soil loading from different crops is hugely
variable (orders of magnitude).

All figures are in pounds of active ingredient per acre (my apologies to
the metric world but it is the comparison that is important anyway):

mustard (read canola as well)          .028
wheat                                              .002  to  .011
barley                                              .004  to  .007
potato                                              .163 to   .325
cotton                                              .063
broccoli                                           .39  to    .42
radish                                              .50   to   .67
corn                                                 .007 to   .011
head lettuce                                     .70  to    2.25
leaf lettuce                                       .68  to    2.26

So there could be 220 times as much loading to the soil in lettuce as in
corn.
There is 1000 fold difference between the low rate in wheat and the high
rate in lettuce.

So even take the most conservative clothianidin half life of just one year,
whatever you grow after lettuce is going to be treated at a higher rate
than label.

I wonder what the level of clothianidin is in dandelions growing up in a
field that was in treated lettuce.

Stan

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html