According to the UN Environment Programme, "of the 100 crop species that provide 90 per cent of the world's food, over 70 are pollinated by bees."
And, as noted in the PBS documentary, Silence of the Bees,
The role honeybees play in our diet goes beyond honey production. These seemingly tireless creatures pollinate about one-third of crop species in the U.S. Honeybees pollinate about 100 flowering food crops including apples, nuts, broccoli, avocados, soybeans, asparagus, celery, squash and cucumbers, citrus fruit, peaches, kiwi, cherries, blueberries, cranberries, strawberries, cantaloupe, melons, as well as animal-feed crops, such as the clover that’s fed to dairy cows. Essentially all flowering plants need bees to survive.Because of this, the precipitous decline of honey bees as a result of "colony collapse disorder" (CCD) is a significant global issue. The New Yorker published a comment that reflects on CCD and reports on the increasing evidence of a connection between CCD and neonicotinoid pesticides. The comment notes that this year marks the 50th anniversary of Rachel Carson's, Silent Spring, also published in The New Yorker, and questions whether we really heeded Carson's message. I encourage all to read it. She makes the case far better than I can. Silent Bees by Elizabeth Kolbert.