Back in June I posted a request for information on the toxicity of the new
formulation of sevin (XT, I believe it is called).  The manufacturer claimed
that once it had dried on the plant the bees would not carry it back into
the hive.  I thought perhaps fellow listees would be interested in my
observations.
 
I moved ten hives into one blueberry field that was sprayed with sevin xt
the day after the spraying.  This field was sprayed only on one side of a
more or less central laneway. I moved eight hives into a field that was
almost adjoining and had no spray.  I did not have any hives die in either
field, but I did see quite a few dead foragers in front of hives in the
sprayed field and I assume there were many more that I did not see.  The
blueberry grower and myself walked through the field in the afternoon two
days after spraying and made this observation:  The honeybees seemed to be
avoiding the sprayed side of the field.  There were many bees on the
unsprayed side and practically none on the sprayed side.  There seemed to me
to have been some difference in the number of bumblebees too, but it was not
obvious as it was in the case of the honeybees and we did not do any
scientific counting.  I do not believe that the dearth of bees on the
sprayed side was due to them dying on this side (the number of dead foragers
was not that great).  I think that the bees were able to sense the pesticide
and avoid it.
 
I was able to use this observation to convince another grower to delay
application until after the bloom.        Regards, Stan Sandler