Research

Colony Collapse Disorder Plagues Virginia's Honeybees

When Colony Collapse Disorder hits, the adult bees in the colony abandon their honey and pollen food reserves and vanish, their bodies nowhere in sight. Entomologist Rick Fell recommends beekeepers fight back with aggressive management practices, such as reducing miticide use and replacing queens frequently.

Each year, Virginia’s honeybees produce more than one million pounds of honey and pollinate dozens of crops, including soybeans, fruits and vegetables, berries, and almonds and other nuts. According to the U.S. Department of Agriculture, a third of the typical American diet comes from foods pollinated by honeybees.

But in the past year, an unexplained phenomenon called Colony Collapse Disorder has threatened this vital industry, including the colonies of Virginia’s more than 2,000 beekeepers.

“The disorder is characterized by an absence of adult bees in colonies with few, if any, dead bees in the hive or in the front of the hive,” said Rick Fell, entomology professor and Extension bee specialist. “We frequently see the presence of capped brood in the colony along with food reserves such as honey or pollen. Strangely, the colonies have not been robbed, and pests such as wax moths have not attacked the hives. Some colonies have small clusters of remaining bees with a laying queen, but the bees do not respond to simulative feeding.”

Although a variety of factors such as starvation, poor health, and parasites can cause bee losses, especially in the winter, the number of losses has risen substantially in the past year, much of it from Colony Collapse Disorder. Last year, more than 50 percent of bee colonies vanished.

Researchers point to a variety of contributing factors. Varroa mites, for example, are a major problem, both as a parasite and as an organism known to transmit disease. Beekeepers have used miticides to control the mites, but recent evidence suggests that the miticides may also cause problems to colony health.

“What we have found is that when we use miticides, we might not only be controlling the mites – we might also be causing significant reproductive problems in our bee populations,” Fell said. He added that sperm viability is extremely important because honeybee queens only mate once during their lifetimes and store sperm for later use during egg laying.

Researchers have also discovered a new microorganism known as the Israel Acute Paralysis Virus, a pathogen that beekeepers may have imported from outside the U.S.

“In the past few months, it has been found that the Israel Acute Paralysis Virus plays a bigger role in Colony Collapse Disorder than we originally thought,” Fell said. “Although the virus is not the definitive cause for collapsing colonies, it does add to colony stress and possibly weakens the honeybee immune system.”

Other possible culprits include the Nosema ceranae pathogen recently discovered in U.S. bee populations, chemical residues and contamination, parasite loads in bees and brood, nutritional fitness of adult bees, stress levels, and lack of genetic diversity. Though once suggested as a possible cause, the use of genetically modified crops is not considered a likely factor because European countries that use few genetically modified crops are experiencing similar colony losses.

To address Colony Collapse Disorder, Virginia Cooperative Extension is training local agents about the problem, offering workshops for beekeepers, and fine-tuning pest management approaches for the control of mites. Extension is also working with the Virginia Department of Agriculture and Consumer Services and the Virginia State Beekeepers Association to create a new curriculum called the Virginia Master Beekeeper Program. Once established, the program will systematize the commonwealth’s beekeeper training through individual certifications, ranging from Certified Beekeeper to Master Beekeeper.