>I HAVE MANY BLUEBERRY BUSHES AND THREE HIIVES OF BEES. RARELY DO I SEE BEES
>ON THE BLUEBERRY BLOSSOMS, USUALLY THERE ARE GOOD CROPS OF BERRIES. WHAT TIME
>OF DAY DOES MOST OF THE POLLINATION TAKE PLACE? WHAT FORM OF  POLLINATION
>TAKES PLACE? ARE THERE OTHER INSECTS WORKING AT THE SAME TIME CREATING A LIKE
>EFFECT?
 
Honeybees are certainly much much worse than several native pollinators
(such as bumblebees, leafcutter bees, and the blueberry bee) at working
blueberries, on a PER BEE basis.  However when you put good strong hives in
the fields you can introduce a massive population and they will have a very
good effect.  I have many satisfied customers.  HOWEVER, YOU HAVE TO MANAGE
THEM PROPERLY TO FORCE THEM TO WORK THE BLUEBERRIES.  Your three hives, Tom,
are probably in the same location all year.  By the time the blueberries are
flowering those hives are working far more attractive bloom to honeybees,
such as (in my area),  dandelions, apple, wild pear, lilacs,...   But if you
were to move hives into fields full of blueberry when one third of the
blossoms had opened, and not before, you would find that on the first day in
the new location those bees would come out and see blueberries and start
working them.  Once they start they will tend to continue working them for a
week or so until scouts have found some other really attractive blossoms.
 
Many blueberry growers get reasonable yields using only the pollinators
already in the area.  However it is my impression that pesticides are
lowering the population of native pollinators quite dramaticly, and the
blueberry growers themselves are one of the culprits in this.
 
Regarding time and form of pollination:
The time could be any time that insects are moving.  The blueberries are not
wind pollinated, they must be visited by an insect to be fertilized.  The
honeybees rarely if ever gather pollen from blueberries, but they fertilize
them incidentally in their gathering of nectar, (as was intended when nectar
evolved).  The bumblebees can "buzz" out large amounts of pollen from the
blossoms using wing vibration.  The honeybees can help in spreading these
large packets around.