With the US honeybee population stable, what are the challenges going forward?

The field signs of the mysterious “Colony Collapse Disorder” that was of great concern during the 2004-2009 time frame is now seldom seen, with the term now being improperly applied to the well-understood collapse of colonies from the varroa/virus complex. There is an excellent article published in 2020 which debunks the gloom and doom assertions and also the simplistic explanation that the problem is driven by the use of certain insecticides.

The truth is that the the number of colonies of bees are certainly not declining and have actually been increasing in recent years (see graph below).

Ever since 2008 there has been a positive trend for bees in terms of the number of commercial hives Credit: Steven Savage using USDA data

Although the industry is doing reasonably well, as with other agricultural enterprises, the beekeeping industry still has to deal with important issues. The bees and the related businesses will be best served by a rational assessment of the challenges and efforts focused on solving them. This article is based on interviews with bee expert Randy Oliver who runs the ScientificBeekeeping.com website, publishes extensively in scientific and industry bee journals, and is a sought-after speaker internationally on bee related topics. From Oliver’s perspective the key challenges fall into three main categories:

  1. Giving beekeepers the tools they need to deal with the parasites and diseases that affect bee health
  2. Having adequate “forage resources” or other feeding options to meet the full-season nutritional needs of the large hive numbers required for the pollination market, and
  3. Anticipating the future impact of climate change and the management of agricultural lands on pollinators, and the business of beekeeping


The North American commercial bee industry is based on a species that was imported long ago from Europe. It is functionally a “managed livestock species” dependent on humans and present in whatever numbers are profitable for the businesses involved (pollination, honey and wax production). For instance the peak number of hives was in 1946. That was because the number of hives was increased dramatically to provide honey as a substitute for constrained sugar imports, and beeswax was a major ingredient for many military applications. It was also used to desensitize gun powder for naval guns, a corrosion inhibitor for brass casings and waterproofing for airplanes, ammunition, and also in motors and electric coils.

Commercial beekeepers adjust the number of hives that they manage to meet demand by splitting them and by providing new queens as needed (there is an entire sub-industry of queen producers). The largest current demand driver for the industry is pollination service for the California almond industry. As that industry grew through the 1980s and 90s it outstripped the ability of in-state beekeepers to keep up with the requirement that growers stock two hives per acre in order to obtain crop insurance. Initially the beekeepers were being paid less than $10/hive, but between expanding acreage and some hive pest issues, supply and demand dynamics eventually drove the offered price into the $150 to $200/hive range. Those prices allowed bee keepers from all over the US to transport their hives to the almond orchards and by 2004 the national pollination services income to the industry surpassed that of honey production. The almond industry has doubled in terms of bearing acreage since that year, and that trend is the driver behind the fact that around 80% of all US bee hives make the trip to California each February. (see graph below based on data from Almonds.com, the California Department of Food and Agriculture and Western FarmPress ).

The California almond industry has been expanding rapidly since the turn of the century – so has the market for pollination services Credit: Steven Savage

1: The Challenge of Parasite and Disease Control

As is the case with any crop or farmed animal species, honey bees have pests. These include recently-introduced parasitic mites, viruses, bacteria, and a microsporidian (Nosema ceranae). In recent years the dominant challenge has been with a parasite called the varroa mite and two lethal viruses that it can transmit throughout a hive.

Honey bees infested with varroa mites (brown ovals are the mites) Credit: Randy Oliver via ScientificBeekeeping.com

The mites have been spread throughout the US at least partially because of the almond-based travel across geographical barriers. Bee keepers nowadays lament that they experience higher rates of colony loss than they did prior to the invasion of the introduced parasites. They are able to rebuild their stocks by buying queens and splitting hives, but this is a major cost. Miticides are used to control varroa, but the mites fairly rapidly evolved resistance to the first two products. Beekeepers then shifted to another miticide called amitraz, but after twenty years of use, the varroa mite is beginning to show signs of resistance with only a limited number of other options in the pipeline.

One very attractive mite control option that has been identified is to use the natural chemical oxalic acid – something that is classified as “exempt from tolerance” for honey by the EPA because it is a natural component of greens such as spinach, and is low in terms of mammalian toxicity. The mode of action of oxalic acid is not fully understood, but it appears to interfere with the mites’ “empodia” which are sticky parts of their feet which they need in order to walk and to climb onto their host, the honeybee. That mode of action is unlikely to select for resistance so it is an attractive option either alone or in combination with other miticides. But the approval of the most efficacious methods for application of oxalic acid is tied up in bureaucratic delay. In New Zealand the government has exempted organic acids and other natural treatments from regulation allowing their bee industry to assume its own responsibility for their safe usage. The US industry struggles to remain in compliance with the limited applications methods of these natural treatments currently approved by the EPA.

Integrated Pest Management of varroa would be based upon the use of mite-resistant bee stocks, biological controls and then biopesticides if needed, along with sparing use of synthetic miticides. Researchers at WSU have used “directed evolution” to select for strains of a biocontrol fungus called Metarhizium which can survive in the heat and humidity of a bee hive and selectively kill the mites. The commercial scale application method needs to be worked out and then it will also need to be registered by the EPA.

The ultimate solution for the “varroa problem” would be the development of mite-resistant bee stocks. A number of groups have been working on such breeding projects for many years, but progress has been slow. Bee breeding is tricky because it happens outside of the hive when the queen goes out in the spring to mate with multiple drones. Randy Oliver – the expert mentioned earlier in this article — has developed an efficient way to measure mite populations on a hive-by-hive basis so that he could track mite infestations in 1000 hives and then selectively breed only from those exhibiting natural resistance to the mite. Over five years of strict selection, he has seen an increase from 0.2% to 20% of his colonies exhibiting strong resistance. With hope, the trait may be something to pass along to the dozen or so “Queen Producers” who supply the rest of the industry with a million queens each year to start new hives. The funding for Oliver’s research and breeding efforts comes from voluntary contributions from members of the bee industry.

2: Full cycle feeding of the bees

Honey yields per hive have been declining since around the year 2000. Climate change and reduced forage availability are likely causes Credit: Steven Savage

Other changes in agriculture are having an impact on the bee business. There has been a slow decline in honey yield per hive since around 2000 (see graph above). There are several likely causes behind this trend, one being extreme weather events related to climate change. Another likely and currently more important cause is the loss of “forage resources” needed to feed the bees. Spring pollination windows for almonds, citrus, apples and blueberries are fairly short in California, the Pacific Northwest and the Southeast. Traditionally many of the bees would be returned to the upper Midwest to spend the summer and fall. There they were able to forage for their food supply on long-flowering animal feed crops like sweet clover or alfalfa, on native prairie species or on weeds that grew along fence rows even in highly cultivated areas. Feeding on this sort of “pasture” is important to sustain healthy colonies, and for honey yield. But over time the row crop farmers in those areas have shifted their planting to higher value crops like corn or soybeans. This is an unusual business intersection since the bee keepers do not normally pay anyone for the access to their land or crops.

There has also been a decline in acreage set aside through the USDA’s Conservation Reserve Program which is another reservoir of plants that are suitable to supply bee forage (see graph below). Bees now need to be artificially fed for parts of the year and there has been a steep learning curve for bee keepers in terms of how to do that.

Conservation Reserve Program Enrollment has been declining. Credit: Steven Strange

So what are the possible solutions? There are active programs to facilitate the planting of pollinator-friendly species around fields and those are promoted by the major seed/chemical companies. Another source of pollinator habitat can be a multi-functional farming system called “prairie-strips”. In that case a mix of native prairie plant species are planted in strips designed to limit soil erosion, prevent nutrient runoff to waterways and also increase regional plant biodiversity all without compromising the efficiency of farming for the rest of the field. This strategy is being promoted by Iowa State University and other institutions.

A prairie strip protecting sloping land from erosion while also providing food for bees and other beneficial creatures. Credit: Iowa State University

There is another beneficial farming practice that can help to address the bee summer forage shortage. Cover crops are plantings that are made within the same fields as crops like corn or soybeans to keep feeding and stabilizing the soil before and after the main cropping period. When combined with no-till or strip-till soil management they are part of best-practice for carbon sequestration – true “climate-friendly-farming.” While not perfectly timed for honeybee needs, expanded use of cover crops could help to some degree.

What might make sense for this challenge is to consider a business model in which bee keepers partner with other farmers in specific areas to employ some of the practices described above and/or to intentionally plant good bee forage crops. Whether the resulting honey income could fund such a system needs to be evaluated.

But looking into the future, the bee industry may become smaller and less almond-centric because the pollination service market could shrink. For one thing the Almond industry has begun been shifting slightly towards “self-fertile” tree cultivars which only require one bee hive per acre instead of two. But there are more consequential trends. A good part of the demand for California almonds is for export – particularly to China and India. Demand in those market dropped during the pandemic leaving the tree nut industry with atypically large carry-over supplies. University of California economists do not think the drop in export demand is permanent, but they have made the following projection: “We expect the growth in California’s production to slow moving forward. Plantings have slowed to the point where, at the present pace, they are unlikely to match removals as trees planted in the early to mid-1990s reach the end of their useful lives.”

3: The Climate Change Challenge

The slowing pace of almond planting predicted above is not just driven by export market demand. It is influenced by the bigger long-term issue that climate change is on track to reduce California’s ability to grow many irrigated many crops including Almonds. Between reduced snowpack, less rainfall, and higher temperatures; the state’s irrigation water resources are seriously strained. Groundwater is being depleted and will not be able to continue making up the difference. Most tree fruit and nut growers are already using highly efficient irrigation systems and other water conservation measures, but there is only so much that can be done. Some almond growers are reluctantly abandoning some of the trees because they don’t have the water to maintain that investment. If the acreage of almonds declines, so will the need for bees. The “upside” of that is that the mismatch with summer forage options will be less problematic, but the downside is that consumers will probably have to pay even more for this tasty and nutritious food. This challenge cannot be fully addressed by technical innovations related to bees or crops. What is needed for many reason are broader societal efforts such as decarbonization of the energy and transport sectors and carbon capture strategies of various types.

Bee hives in an Almond orchard Credit: Randy Oliver


Overall the honey bees of the US are doing OK, but it could be easier to keep them healthy if key regulatory approvals could be expedited. On the up-side, it may be possible to integrate genetic resistance into the control strategy for the troublesome varroa mites. There are ways to enhance the supply of bee forage options, but the economic incentives to do so need to align. Climate change is probably going to force adaptations of many agricultural sectors including that of beekeeping.

#honeybee #population #stable #challenges

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