In the winter of 2006/2007, more than a quarter of the country's 2.4 million bee colonies -- accounting for tens of billions of bees -- were lost to CCD, Colony Collapse Disorder. This loss is projected have an $8 billion to $12 billion effect on America's agricultural economy, but the consequences of CCD could be far more disastrous.

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.

A daunting question is: If honeybee colonies were so severely affected by CCD that pollination stopped, could we lose these crops from our markets and our diets forever?

"We're not there yet," says Jeff Pettis of the USDA. Pettis says there are steps researchers and beekeepers can take to ensure that the bee population doesn't plummet to catastrophic levels. "One measure beekeepers have been taking is to keep bees as healthy as possible -- improve nutrition and reduce stress," says Pettis. Consumers have become more demanding and expect to have fruits and vegetables available to us all year round. In order to achieve this, commercial beekeepers haul colonies of honeybees across the country so their pollination services can serve all growing seasons. The season may start with almonds in California, then move on to apples in the Northwest, cranberries in New Jersey and Maine blueberries. The constant moving about places stress on the bees. In addition, certain crops that may be in the pollination circuit, like cranberries and cucumbers, are not very nutritious for bees. To keep the bee's health, beekeepers may need to ease up on their schedules. It may be necessary for them to retire bees for a particular season or skip some less nutritious crops entirely.

Of course, nature has its own safeguards to keep crops pollinated. Honeybees aren't our only pollinators. Other insects and birds pollinate fruits and vegetables as well. The problem with other natural pollinators picking up the bees' slack is that today's agricultural industry has simply grown too large for them to keep up. The leviathan that is U.S. agriculture creates a huge demand for pollination. Because honeybees are relatively mobile and can pollinate a generous number of crops, they have been the ideal recruits to meet our crop needs. But honeybees don't perform such feats naturally without help -- lots of it. Commercial beekeepers keep colonies nourished and healthy and move their hives from state to state in semis, selling their pollination services to farmers at a premium.

With the threat of CCD looming, researchers are starting to study how other pollinators like the larger bumble bees could step in for honeybees. "The Dutch have figured out how to use bumblebees," says Pettis. Bumblebees share many similarities with honeybees. Both are social nesters, although the bumblebees' society is not as highly ordered as that of honeybees. Also, bumblebees make a new nest each spring by solitary queens, who hibernate through the winter. Honeybees remain in the old nest.

Perhaps the biggest consideration is a financial one. Bumblebees last just 2 months and cost $200 per colony, whereas honeybees can last several months in the summer with colony rentals running only $100 to $140. As a result, the use of bumblebee pollination is usually confined to high-value crops like tomatoes. Clearly, the use of bumblebees is a step in the right direction, but not a final solution.

"There's nothing waiting in the wings that can replace honeybees at this time," says Pettis, "but we can solve the problem in honeybee health." Pettis says that by focusing on reducing stress and improving nutrition, beekeepers can limit some of the factors that potentially lead to disastrous conditions like CCD, thereby keeping bees -- and our diets -- healthy.

It was a mystery that left scientists around the world buzzing for answers. Last year a mysterious and deadly plague silently worked its way through bee colonies, leaving millions of dead bees in its wake. The killer was coined as CCD or Colony Collapse Disorder. It had moved in suddenly and unexpectedly, and left so few clues, experts could not crack the case.

Luckily this past September, there was a big break in the case. A team of scientists led by the U.S. Department of Agriculture (USDA), Pennsylvania State University, The Pennsylvanis State Department of Agriculture and Columbia University linked CCD with a virus imported from Australia, IAPV or Israeli Acute Paralysis Virus. Over the past three years, genetic tests on bees collected from stricken colonies around the U.S. found the virus in 96 percent of bees from hives affected by Colony Collapse Disorder.

IAPV had not historically been present in U.S. bees. In fact, it was only discovered in Israel in 2004, the same year American beekeepers started importing packaged bees from Australia. "Before that, nobody knew to look for it," says Jeff Pettis of the United States Department of Agriculture's Bee Research Laboratory. "As people began to look for it, it was found in China, Australia and the U.S."

Though the discovery of IAPV was indeed a big break, the case of CCD was not closed. Scientists have much to learn about how IAPV affects colonies and how it may have brought on CCD. Future studies will tell researchers if they are dealing with just one strain of the virus or if there are other strains to look for. "Discovering the IAPV was a lead but not the end of the story. We're looking at IAPV as a marker. It's there. It's present in colonies but viruses by themselves are not known to be that dangerous," says Pettis. Pettis and other scientists believe that CCD is not caused by one single factor, but by a whole host of forces including pesticides, parasites, poor nutrition, and stress. Any of these may leave bees vulnerable to infection and make IAPV lethal. "We know all of those things have affected bees in the past," says Pettis. "We have to look at combinations of factors."

Researchers at Penn State University and the USDA are planning a complicated set of experiments where they stress bees in certain ways and evaluate the effect on their health. The tests will hopefully indicate whether IAPV causes CCD by itself or if it is triggered by other pathogens and stresses.

Some studies on IAPV have already brought positive news. Israeli researchers say there is a possibility that IAPV-resistant bees can be bred. A third of bees sampled in Israel have incorporated the virus into their genome. In experiments, almost 20% of these bees survived when injected with IAPV.

While the work is ongoing and answers are sought, until the government declares otherwise, the nation's borders remain open for bees. Packaged bees are being brought in from Australia, which has yet to report cases of CCD colonies. Though researchers are still searching for answers, they are considering whether stressors that disproportionately affect U.S. bees such as pesticides, poor nutrition or pests like varroa mites might trigger the virus, making it virulent.

Last year, imports from Australia and New Zealand made up only 5 percent of the bees needed just for almond pollination (though almond pollination represents half of our need for honeybee pollination services).

Case closed? Not yet; but at least the prime suspect is now in custody. In the meantime, beekeepers must take measures to keep bees as healthy as possible. The goal now is improved nutrition, reduced stress, and better overall health for bees. Many beekeepers have been able to achieve just that. Over the summer, many experienced beekeepers had been able to build up the number of bees in the colonies over the summer. However, Diana Cox-Foster of Penn State University and a lead researcher on the team that discovered IAPV in U.S. bees says there are some reports now of CCD making a reappearance, though mainly in the colonies of less experienced beekeepers. If CDD continues, researchers like Cox-Foster are concerned that we could see major problems in honeybee numbers next Spring. She explains that beekeepers were able to restore colony numbers this year, but the weather was in our favor. Next time, we may not be that fortunate. If it strikes again, CCD could have disastrous impacts on U.S. agriculture -- causing prices to soar and threatening the availability of some crops. Among the most vulnerable crops are almonds -- a crop that completely depends on honeybee pollination. But foods like apples, berries and alfalfa seeds, which is fed to dairy cows and livestock, will be in peril as well. "It's still fairly early," says Cox-Foster. "It's still a concern that some people will continue to have problems with CCD but the verdict is out."

How Can You Help The Bees

While researchers probe deeper into understanding CCD, or colony collapse disorder, and beekeepers work harder to improve bee health, ordinary citizens can help the honeybee too.

Go Retro -- Become a Backyard Beekeeper

Over the years, our diets have increased the demand for a constant stream of all-season fruits and veggies. Such demand hasn't bypassed the bees. It's turned bee pollination into a year-round service and beekeeping into a commercial industry. Today, there are half as many beekeepers as there were two decades ago, and the remaining beekeepers are mostly large-scale pollination services with thousands of hives and millions of bees. But there was a time when beekeeping was much more of a hobby than a commercial industry. "Beekeeping is a graying hobby," says Jeff Pettis of the Dept of Agriculture. Joining the ranks of backyard beekeepers can not only infuse the dying hobby with life, it can strengthen the bee gene pool by adding healthy local bees to the mix.

If you're interested in becoming a backyard beekeeper, experts recommend starting with a local beekeepers' association to learn about keeping bees alive and healthy. It's important that bees are adapted to the local climate, so you'll want to start with a local source for bees. Aside from contributing to the bee population, just two hives can pollinate an entire mid-sized residential garden. You might just find yourself with a lifelong hobby. For most people, beekeeping grows into a passion.

Get Closer to Nature

If you decide to pass putting on a beekeeper's suit, merely keeping a backyard bee garden is another good deed you can do for the honeybees. With rapid urban development limiting their foraging habitat, backyard gardens can offer a welcome supply of nectar and pollen for honeybees.

Cultivating plants that will attract bees is the most important task of a bee gardener. Choose flowers that bloom successively over the spring, summer, and fall seasons such as coreopsis, Russian sage, or germander in order to provide pollen and nectar resources to the native bees of all seasons. If you're not sure what to choose, you can always check with a local garden center for their advice on "bee-friendly" florals. To improve bee visitation, the garden should contain large patches of like flowers planted in close proximity to one another. Diversity is a key factor in keeping bee gardens buzzing. Researchers have found that more bees will be drawn to gardens with ten or more species of attractive plants.

As you diversify your garden, keep part of it wild because bees prefer that to a manicured space. Go for a "planted by nature" effect rather than a perfectly pruned garden. Remember: bees don't discriminate between weeds and cultivated flowers, so let those dandelions grow.

And of course keep your bee garden free of pesticides -- a danger in any garden. Some pesticides can kill the bee before it returns to the hive; other pesticides get carried back and can harm the rest of the hive.

If, after all of your hard work, you're still not seeing bees in your garden, it's not a wasted effort. Growing a pesticide-free garden is also good for you if you're growing fruits and vegetables. Robert Mandela, President of the Backyard Beekeepers Association, says, "Even if there isn't a hive of honeybees within a couple of miles of your garden, gardening brings the grower closer to nature and closer to realizing that what s/he grows is more nutritious and tasty than the 'factory-ized,' perfect, unblemished, and perhaps pesticide-covered" produce.

Even if you don't have a green thumb, buying pesticide-free foods at the market also protects humans and bees from pesticide poisons.

Give the Bees a Voice

"Something the average person can do," says Mandela, "is to write to their senators and representatives in congress on the federal level and to do the same on the state level to support funding of honeybee research. This support has fallen off over the years."

The news focus on CCD makes it an ideal time to put pressure on politicians to reinstate laws that used to prevent importing bees into the country and transporting them across state borders.

Large or small, any effort you make to help bees or increase awareness is a step towards healthy bees, healthy crops, and, consequently, healthy humans.

PBS - Nature - Silence of The Bees