As a beekeeper here in the Niagara Peninsula I share and understand this  
situation.
Commonly guthion and other sprays have been used . Spraying is always done  
after the blossoming and then Sevin is commonly used as the apples  develope 
when the producer wishes to thin the apples on the trees. This is  a delicate 
spraying situation that if the concentration is not perfect will  cause complete 
crop loss or a very poor crop.
Obviously if there is a residue in such an amount that bees can pick it up  
then the people spraying it no nothing about what they are doing and need to  
be educated not only from the toxicity standpoint but also the  contamination 
aspect of the surrounding area.
I feel the beekeeper is obligated to discuss spraying habits with the  
property owner where bees may be affected simply as a measure of insuring the  
safety of ones own bees.
 
A good farmer will spray only when weather conditions are right  and  most do 
it early morning well before the bees fly so that the spray dries  
appropriately
.  At one point I covered my bees for the interm since weather  conditions 
forced a change of scheduling and wind direction was not favourable  for the 
spraying to take place.
 
 



   

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