Honey bees are easy to transport and establish in the orchard at flowering time, and are essential in the commercial production of both plums and prunes. The blooms are usually attractive to bees all day but more so in the morning. The plums and prunes, like other stone fruits, require that only one viable pollen tube reach the ovary to produce a fruit, but this pollen grain must, in most cases, arrive from another compatible blossom and at the right time. To assure that such pollen reaches the maximum number of flowers to produce the plum or prune crop desired, a heavy population of pollinators is required. This only occurs when proper pollenizers are interplanted and bees are present in large numbers.
Most growers take some steps to see that bee colonies are in or near their orchards.
FREE, J. B. 1962. Leaflet 378, rev. Leaflet 163, n.p. Calif. Crop and Livestock Rptg. Cir. 62, rev.