(CBS) In spite of all the advances in agriculture, honeybees remain indispensable. By moving pollen from flower to flower, bees are the only efficient way for many crops to pollinate, CBS News correspondent John Blackstone reports.

As growing season begins in California's Central Valley, there is nothing quite as busy as a beekeeper. Farmers pay them to put their hives in their fields and orchards.

"It means the difference between profit and loss for them," says beekeeper Lance Sundberg.

But beekeepers like Sundberg have a mystery in their hives this year. Bees are disappearing at an alarming rate.