July 6, 2013 Updated: July 6, 2013 at 9:55 am
Paul Campanis lost half of his beehives on his 16-acre Nashville farm this past winter.
Nashville gardener David Davies has seen so little honeybee activity this spring that he's resorted to using a paintbrush to pollinate his tomato and squash plants.
The nation's honeybees are dying off in record numbers and researchers, including at the University of Tennessee, are scrambling to figure out why. The stakes are high.
As much as a third of the nation's food supply relies on bees and other insects for pollination. In Tennessee, everything from blueberries and strawberries to pumpkins and watermelons need the bees.
But since 2006, bees have been dying at alarming rates. About one in three honeybees died this past winter, a nearly 10-percentage-point spike compared with the winter of 2011-12, bee researchers reported in May.
Figuring out why bees are dying off is a tough puzzle, said John Skinner, a University of Tennessee professor and bee researcher involved in the national effort to find answers.
"We are at the middle of the tunnel. We are closer to seeing the light," Skinner said. "It's a challenging time. It is probably one of the most exciting times in bee research. But at the same time, people want a quick answer and we simply cannot give that."
Pesticides a hot issue
A study on bee health released in May by the U.S. Department of Agriculture and the U.S. Environmental Protection Agency suggested a host of factors are contributing to the rising death toll.
Those include parasites and disease, poor honeybee nutrition and a lack of genetic diversity among bee colonies. The report also suggested exposure to pesticides may play a role in killing bees, but noted that additional research is needed.
The role pesticides play in killing honeybees is a high-profile issue. Many environmental groups - and local beekeepers - say it is a significant factor. Protests took place across the nationrecently, including in Nashville, against Monsanto, the Missouri-based agriculture giant that produces everything from pesticides to genetically modified seeds. The bee issue was among the concerns for protesters.
Last month, the European Union approved restrictions on three pesticides to better protect bees. Environmental groups praised the decision, although chemical companies opposed the restrictions.
Mite a key culprit
The new report on bee health said a parasitic mite - called the Varroa destructor - remains the "single most detrimental pest of honey bees" and a major reason for the declining bee colonies.
Skinner said the mites can kill the bees, and researchers have found viruses that also are playing a role. Bees can often carry viruses from plant to plant, he said.
As for pesticides, most people say they are a factor in some way, Skinner said. But to what extent is hard to tell, he said.
Pesticides can serve as a medicine in small doses but prove harmful in large quantities, he said.
"We need more research to look at it more carefully," Skinner said.
A big problem
Regardless of the reasons, the rising honeybee death toll is a serious matter - not just for large-scale agriculture but for backyard gardeners, too.
"Some people don't realize the value of pollination," Skinner said. "It is huge."
Jim Garrison, a member of the Tennessee Beekeepers Association, said mites and pesticides play a role. But so does the weather. Mild winters mean bees become more active earlier but then lack needed food.
"It is a constant problem," he said. "We had a lot of die-off this last year."
W.T. Nolen, 84, a Lebanon, Tenn., beekeeper and member of the Wilson County Beekeepers Association, said bees can't live on their own today because of all the diseases.
"As beekeeepers we try to provide them a home and resources so they can do our pollination and with a strike of luck reward us with some honey," Nolen said.
Campanis and his wife, Melanie, rely on their bees to pollinate their large vegetable garden. They are trying to do all they can to make sure their bees have food and a good home. They let some of their vegetables flower and go to seed to provide them more food, something larger farms don't do.
Companis and his wife started with eight hives last winter and began the spring with three. They captured a bee swarm and now have four. "It's just devastating," said Campanis, a past president of the Nashville Area Beekeepers Association. "We have to have sustainable agriculture practices."
Davies just wants to make sure he can have squash and tomatoes this year.
"I've got a bunch of big tomato plants, taller than I am, but there are no bees," he said. "Nothing."
Davies knows he needs to do more. "I am going to start beekeeping," he said.