What is the mechanism that has apparently caused honeybees to avoid the blossoms of some fruit trees and other food crops while they continue to forage on the blossoms of non-food crops? Does this have anything to do with the 5G cell phone technology and the chemicals and the nanotech being delivered in chemtrails and other sources?

This, in fact, is interrelated, as improbable as that might seem. Bees are very sensitive to electromagnetic fields and perturbations on various frequencies. It is a simple matter for the extraterrestrials to beam such radiation into the environment and create large swaths of terrain that become inhospitable to honeybees because the energies are negative and drive them away. This allows a highly orchestrated system that can be programmed and fine-tuned to create bee-unfriendly zones, so to speak, and thereby reduce the population of plant life of greatest benefit to humanity because pollination will be restricted. This has a dual negative consequence because it will also restrict the success of the bees themselves which benefit from collecting the pollen to begin with.