> I work on a crop- cranberries, which requires honey bees for pollination.
 
I worked on raspberries and other top fruit
 
> Does anyone have data/experience that sublethal doses of an insecticide like
> guthion will dramatically reduce pollen collection by bee for long periods
> following spraying?
 
A number of insecticides and fungicides have repellant affects, this
reduces foraging on the crops following spraying.  This has been
observed in the field and confirmed in published papers.
 
> Does anyone have experience with sevin XLR - it is suppose to be fairly safe
> if it can dry on the leaf surface. What about if it gets rewetted after
> spraying by irrigation? Is it now more toxic than before?
 
If you are refering to Sevin that I used to use on top fruit post
blossom, it is absolutely deadly when sprayed as it is carried back
to the colony on the pollen and has effects for months to come.  The
wetting and drying effects you mention have not been observed.
 
My guidelines were always to spray very early or very late in the day
and with chemicals that were environmentally as well as user friendly
 
Keith
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