Scientists and stakeholders on the leading edge of honey bee health came together last fall during a national workshop focused on current and future issues facing domestic honey bees and the growers who rely on them to pollinate their crops.

The joint USDA-EPANational Stakeholders Conference on Honey Bee Health, held in Alexandria, Va., brought together leading national honey bee researchers to explore the status of various factors on honey bee health. The meeting not only highlighted what has been learned from some five years of research on Colony Collapse Disorder, but also helped inform the USDA as it focuses federally funded honey bee research over the next five years. 

Some 1.6 million honey bee colonies are brought into orchards annually to pollinate the state’s almond crop. That number is expected to grow as new acreage reaches maturity in coming years. At the same time, a number of stressors are putting a strain on beekeepers and their hives.

(See related: Honey bee losses defy solitary explanations)

The workshop highlighted areas crucial to the sustainable future of domestic honey bees in the United States.

The first day of the meeting provided background information on the issues and concerns of various stakeholders as well as the current status of knowledge on aspects of honey bee health in the areas of bee biology, nutrition, and pest management; the impact of pesticides; and bee breeding and genetics. The following day, attendees were divided into breakout groups to provide feedback to USDA on priorities for research in each of these broad categories.

Later, researchers from throughout the U.S. offered overviews and updates on their research, as well as the major issues facing domestic honey bees.

Stressors lead to decline

Overwintering hive loss, while lower last year, has jumped from 15 percent  17 percent with the first appearance of Varroa mite to around 30 percent in recent years, said Jeff Pettis with USDA ARS in Beltsville, Md. The decline is likely a result of starvation and poor queen health brought on by stressors, including Varroa mites, lack of pollen and nectar supplies, pesticides and pathogens. Colony Collapse Disorder is caused by some mixture of these stressors, though the exact components are unclear. Pettis emphasized reducing the impact of Varroa mite through a mixture of breeding and treatment. He also called for more standardization in treatment techniques and definitions of hive health to better compare results of treatments and inspections.

Jay Evans, also with USDA ARS Beltsville, noted that the genome has now been sequenced for the honey bee and also for Varroa mite. This could lead to new genetic techniques for improving queen health and conferring pest resistance on domestic bees. Evans also discussed the impacts of various bacterial and microsporidial diseases.

Gloria DeGrandi-Hoffmann, USDA ARS Tucson, shared information on a hive development model that allows researchers to assess the impact of various stressors on the chances of hive survival. She also discussed the nutrient profiles of various pollens, and how pesticides impact in-hive food sources created from the pollen and nectar that bees bring to the hive. Almond pollen is of high nutritional value to honey bees.

Nancy Horn at Yale University is researching microorganisms in the honey bee gut, their role in honey bee nutritional status and susceptibility to diseases and pests, and how pesticides may affect the balance of those microflora.

Honey bee diseases

Diana Cox-Foster at Pennsylvania State University discussed changes in honey bee diseases. Since 2006, there has been a significant increase in the number of different viruses detected in hives, many of them associated with poor honey bee health. Cox-Foster is looking at the impact of diseases on bee behavior and colony health and interactions with pesticides. She hopes to develop tools to deactivate viruses, as well as resistant stock for various diseases.

Penn State’s Dennis van Engelsdorp provided an update on various honey bee pests. Varroa is by far the biggest problem; colonies with more than seven mites per 100 bees are unlikely to survive the winter.

Miticides lead to healthier colonies, although there is documented resistance to fluvalinate and coumaphos, which are used to treat Varroa mites. Van Engelsdorp encouraged the use of mite-resistant breeding stock.

Reed Johnson with Ohio State University discussed research on the impacts of pesticides on the health of individual bees and colonies. More than 119 different pesticides have been detected on bees and in bee colonies. Research has found that Varroa miticides become more toxic to honey bees when the bees have been exposed to a number of fungicides.

Much of the research cited at the workshop reflects research priorities the Almond Board of California (ABC) has identified and funded in recent years. Each year, the Almond Board funds between $100,000 and $125,000 for research related to honey bee health.

Currently funded research projects are focused on improving genetic diversity in honey bees to enhance resistance to pests and diseases, and to transfer that technology to bee breeders for integration into commercial breeding stock. Additional research in cooperation with Project Apis m. seeks to encourage almond growers to provide forage before and after bloom as a supplemental food source for honey bees in almond orchards; this can optimize the health and chances of survival of overwintering bees, and thereby improve pollination.

Colony strength evaluation

Almond Board funding in 2012 helped support the development of a new online learning program through UC Cooperative Extension that provides growers, beekeepers and apiary inspectors with easily accessible, standardized information about honey bee biology, recommended colony strength evaluation practices, and important honey bee diseases, pests and parasites. The online program can be accessed through the University of California online learning website at http://ucanr.edu/ColonyStrength.

Another important new cooperative research project will examine the effectiveness of differing colony densities per acre on pollen transfer and almond nut set. Work so far reaffirms the standard of two eight-frame hives per acre.

Meanwhile, ongoing ABC-funded research is also helping to develop tools to control Varroa mites and other bee pests, and to facilitate understanding of the potential impact of fungicides used in almonds on honey bee development. Almond growers in the past have also supported research into Colony Collapse Disorder and in-hive supplemental food sources for honey bees.

While the workshop validated that the almond industry is on the right track, it also made clear that more needs to be done to meet the mounting demand for healthy honey bees by California growers in the future.