Protecting Our Honeybees: A Reflection on Current Research about Honeybee Population Decline in the U.S.

Sarah Parsons

Honeybees are what some may think of as whimsical, mythological creatures that turn flowers to fruit.  According to the EPA and USDA, their Midas touch, helps to produce approximately one-third of the food and beverages we consume in the U.S. every year¹. In recent years, however, honeybees have seen a rapid decline.  Farmers across the U.S., who for years have relied on honeybee hives to pollinate their crops, have reported large numbers of colony loss.  For many years, the reason for honeybee decline has been an enigma. As a result, researchers at universities across the nation have been working to better identify the factors contributing to honeybee colony losses in the U.S¹. Earlier this year the EPA and USDA released a statement that reported on research compiled by the 2012 National Stakeholder Conference on Honeybee Health, a network of federal researchers, managers, and researchers at Penn State University¹. Research of the conference revealed that honeybee population decline in the U.S. was the result of a number of different co-existing factors. The results of the study are listed below. For a more in-depth analysis of the May USDA study visit my recent blog post.

• The parasitic Varroa mite and a new virus species, causing Colony Collapse Disorder (CCD), are largely contributing to honeybee colony deaths across the U.S.  In addition, the Varroa mite is increasingly becoming resistant to chemicals, used to kill the mite¹.
• Genetic diversity is lacking in many honeybee colonies in the U.S., resulting in decreased resistance against the Varroa mite and other diseases¹.
• Poor nutrition among colonies, resulting from pesticide-treated crops and lack of diverse forage, is also decreasing disease resistance among colonies¹.
• A lack of coordination between growers and beekeepers on best practices, with regard to pesticides and bees, is contributing to colony loss¹.
• Pesticides present a challenge to bee health and more research needs to be done to explore pesticide exposure and effect on bee health¹.

Since the release of the USDA’s statement in May, however, newer research has emerged. In July of this year, scientists from the University of Maryland and the U.S. Department of Agriculture published a study that narrowed the list of factors thought to contribute to Colony Collapse Disorder (CCD), currently one of the larger killers of honeybees in the U.S². The study revealed that a combination of popularly used pesticides and fungicides are contributing to a decreased resistance in bees to the parasite that causes CCD². Prior to the release of this study, fungicides, were not thought to harm insects or honeybees². Many pesticide labels caution against applying pesticides in the presence of pollinators and honeybees, whereas fungicides usually do not.

This latter point is the reason for my post today. The Master Gardener curriculum teaches us, as Master Gardeners and home gardeners, to use pesticides with caution. I anticipate in the near future, however, that the curriculum will also more heavily emphasize caution with fungicide application as well. Honeybees are vital to our food system, and as gardeners, farmers, and growers we need to protect them. We need to remember the mantras of the Master Gardener program and recite them to all our gardener friends and acquaintances

• Buy disease-resistant plants when possible and keep your plants healthy.
• Use preventative measures first, before you resort to using pesticides or fungicides.
• If a disease problem appears on your plant, assess if the disease will dramatically decrease the plant’s productivity or quality of life, before applying chemicals or fungicides.
• If pesticides must be applied, apply with caution.

And now I would like to add my own mantra.

• If fungicides must be applied, apply with caution.

According to materials available through the Ohio State Extension office, fungicides should be reapplied at 7-14 day intervals if a fungus problem has been identified, and a spray method should be used to ensure complete coverage of the plant³. NC State Extension materials addressing apple tree fungus problems recommend applying fungicides after blooming has completed⁴. For some plants, such as tomatoes, fungicides may need to be applied while plants are in bloom. If this is the case, I would caution to be careful not to spray flowers if possible. Flowers are where bees have direct contact with the plant. Also be sure to only spray fungicides on the plants you wish to treat. The research study from University of Maryland, found that honeybees rely on the pollen of many native flowers to feed the hive². Fungicides and pesticides that fell on these native plants, therefore, were of particular risk to honeybee health. Do not spray plants outside of your garden or vegetable bed.

Honeybee health is of great importance to our nation’s food system. According to one statistic from Bloomberg, honeybees pollinate many of our nation’s crops.⁵ Collectively these pollinated crops bring in approximately $15 billion in revenue to the U.S. each year. We, as Master Gardeners and home gardeners, have the opportunity to play a valuable role in helping protect our honeybee populations. Spread the word about taking precaution with pesticide and fungicide application, and let us together protect our bees, our gardens, and our food system.