geraldo,

Some people missed their calling. My older brother is one of them. He sould have been a english teacher, or is it grammar teacher. He's constantly correcting my way of speaking.

Back to subject at hand. 50' is plenty close for pollination. If I recall correctly, honeybees fly up 1/2 a mile. You could also setup some Mason bee shelters. Take a non-treated 4" x 4" and drill 5/16" holes in it. Hang them in your fruit trees. Orchard bees stay closer to home and fly in weather a honeybee wouldn't.
{{gwi:122479}}

If you build them, they will come.

Eric

Here is a link that might be useful: Orchard Bees

Grafting pollenizers directly unto the branches of your pluots would be the most efficient way.

Would a pollinator make several hundred roundtrips zipping back and forth several feet from a pluot pollinizer to the pluot to intentionally pollinate the trees?

Rather, the pollinators would most likely forage from flower to flower in THE SAME TREE before they head back home to unload the nectar and pollens and then visit the same or another tree. So grafting a pollenizer in strategic places in the same tree has TREMENDOUS advantages, and grafting is not that hard to do. Fall season is coming up next, and you can graft this fall and it will bloom next spring just in time.

One of the hardest to set fruit in our area is Flavorella plumcot. Practically I got superb fruit sets this year when a proper pollenizer was grafted directly in different strategic places in the same tree.

This point of view may not have been taken into account in today's development of current fruit cultivars. Many fruit bearing plants may have pollens that last very long being carried by pollinators for that matter as the pollinators would head back home, unload, and then visit the same or another tree. The tree's pollens should survive that. The pollen's survival has never been considered as a selection factor into the development of today's cultivars. As an example of what we are doing with today's plant breeding is to emasculate the stamens, then enclosed the flower after dusting off with generous amounts of pollens. The same with testing at the plant breeders fields, the trees are practically kissing each other when testing for pollination. And when the home owner tries to grow the same trees and their pollinators a few feet away, things like fruit sets doesn't happen.