Hand pollination
This idea is old - it has been used in date production for hundreds, maybe thousands of years. Date palm is a good example.
Date palms are single sex (monoecious); so to maximize fruit set, female trees (which normally rely on the wind for pollination) are commonly pollinated by hand.
The number of male flowers from a single date palm is enough to fertilize 40-50 female trees.
This allows the farmer to limit the number of male trees required to two or three per field.