My dad first started using an apiarist on our vegetable farm in the mid-60's. We saw an increase in cucmber yields in the first two weeks. The Bees represent a major factor in crop yield.
I remember reading, back in the '60's, that Bee activity was affected by the prescence of Power Transmission Lines. I wouldn't be at all surprised if Cell Phone transmissions are to blame for the disappearance of Bees. Another example of the Arrogance of Man.