The best work I know of regarding hazards of insecticides to honeybees is
done by WSU people.  I suggest you contact Daniel Mayer at Prosser.  His
phone number is (509) 786-2226.  He and Carl Johansen (now retired) have
done most of the work on this subject.
 
 
>I work on a crop- cranberries, which requires honey bees for pollination.
>One problem we have is that farmers have to spray for fireworm when the bees
>are still being used. Most farmers wait until the bees are gone until they
>spray, others spray at night. By the next day their  doesn't usally appear
>to be too much effect on the bees. I am evaluating the merits of various
>insecticides that are labelled on cranberries for their abiltiy to kill
>fireworm yet have no effect on the bees.  One of the big problems are that
>the insecticides are usally put out throught the irrigation system - ie high
>volume 500-1000gpa.  This tends to reduce efficacy.
>
>My questions are these -
>
>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?
>
>Does anyone have experience with trying to reduce bee poisoning by
>irrigating the spray off in  the morning, following an evening spray?
>
>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?
>
>