Are beeswax cappings contaminated with pesticides?

Final Report for FS12-261

Project Type: Farmer/Rancher
Funds awarded in 2012: $3,500.00
Projected End Date: 12/31/2013
Region: Southern
State: Virginia
Principal Investigator:
Elizabeth LeGall
Meadows Edge Farm
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Project Information


Beeswax cappings obtained during honey extraction from 10 apiaries in Virginia and North Carolina were analyzed for pesticide residue. One sample (10%) had no contaminants detected. Nine samples (90%) contained one or more detectable contaminants, but overall contained 50% fewer contaminants than found in beeswax foundation. The top two contaminants were fluvalinate and coumaphos but at significantly lower levels than found in foundation samples in a previously published report. Although the sample size was small, results suggest capping wax is a potential source of less contaminated wax for use in creating wax foundation for honey bee brood chambers.


Honey bees as primary pollinators are vital to successful agriculture. The ongoing decline of honey bee colonies threatens crop production and the food supply. Since 2006, one-third of honey bee colonies in this country have been lost over winter. In 2011, 39% of Virginia colonies and 30% of North Carolina colonies did not survive the winter. The overwinter losses as well as continued losses from Colony Collapse Disorder (CCD) have lead to multiple research projects investigating the link between pesticides, overall colony health and CCD. Most chemical residues are lipid soluble and accumulate in wax. Research has shown, over time, the accumulated pesticides can have harmful effects on developing bee brood that is reared in the wax cells. Beekeepers have been advised to rotate out old frames of beeswax on a regular basis and replace with new frames of beeswax foundation for the honey bees to create new wax comb to raise developing brood. Unfortunately, researchers at the University of Pennsylvania have found commercially available beeswax foundation can have very high levels of pesticides(1). All samples of commercially available beeswax foundation they tested were contaminated with a total of 27 pesticides. The top two contaminates were fluvalinate and coumaphos, pesticides some beekeepers use to control Varroa mites. Of the samples tested, 100% contained fluvalinate and 95% contained coumaphos, at alarmingly high levels. These findings are of considerable concern since purchasing beeswax foundation appears to be a route of placing high levels of pesticides inside honey bee colonies even for beekeepers practicing chemical-free beekeeping.

Honey bees store nectar from flowers in honeycomb. It is converted to honey then “capped” by the bees with a layer of new white wax when the honey is cured. It is at this point the beekeeper knows the honey is ready for harvesting. On harvesting, the white wax “cappings” are removed and the honey extracted. The cappings are typically melted down for various uses such as making candles. Since the cappings are in the hive for such a short period of time and chemical treatments are not permitted in the hive while honey is being collected for human consumption, it is less likely it has been exposed to pesticides. Wax cappings could provide a potential source of uncontaminated or less contaminated wax to be used as foundation in the brood chamber. Prior to this project, no research project has investigated pesticide residue in wax cappings.

1. Mullin CA, Frazier M, Frazier JL, Ashcraft S, Simonds R, et al. (2010) High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health. PLoS ONE 5(3): e9754. doi:10.1371/journal.pone.0009754

Project Objectives:

The objective was to determine if beeswax cappings would be a potential source of uncontaminated or less contaminated wax for use in making wax foundation for use in honey bee brood chambers.


Materials and methods:

Apiaries were recruited from two beekeeping clubs, one in urban/suburban Virginia and the second in rural NC. Interested beekeepers were asked about current and past miticide and pesticide use in the apiaries. All beekeepers selected for participation reported never using the miticides coumaphos or fluvalinate in bee colonies. During honey harvesting, wax cappings were collected from 10 different apiaries, five from each beekeeping club. Samples were analyzed for pesticide residues by the USDA, National Science Laboratory in Gastonia, NC. The laboratory and procedures were the same as used in the study of six commercial and two private sources of beeswax foundation performed by University of Pennsylvania Department of Entomology, allowing for a direct comparison of results.

Research results and discussion:

One capping sample (10%) had no detectable level of pesticides. The remaining nine samples (90%) contained 1 or more detectable pesticide, ranging from one to seven contaminants per sample, with a mean of 3.9 detections per sample. In contrast, 100% the 21 samples of beeswax foundation analyzed by University of Pennsylvania contained pesticide residue with 5.7 detections per sample. Overall a total of 13 contaminants (no systemic pesticides) were detected in the capping samples compared to 27 (including 5 systemics and 1 partial systemic pesticide) in the foundation samples. (Table 1)

In this study, as in the foundation analysis, the two most common pesticides detected were miticides used by many beekeepers, fluvalinate and coumaphos. However, median level was 4.4 fold less of fluvalinate and 42.8 fold less for coumaphos. (Figure 1) Interestingly, the study participants reported never using either of the two agents in the apiary. Contaminated wax foundation or wax coating on plastic frames could explain the presence of these chemicals in capping samples since research has shown pesticide residues quickly diffuse through wax or across comb surface in an active honey bee colony.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:
  • Scheduling presentations to local beekeeping clubs
    Preparing article for local beekeeping clubs newsletters
    Planning “Letter to the Editor” for Bee Culture magazine
    Suggesting workshops for preparing foundationless brood chamber frames at state (VA, NC, SC) and regional beekeeping meetings (EAS)

Project Outcomes

Project outcomes:

More beekeepers are becoming aware of the universal contamination of beeswax foundation and the potential synergistic effects of multiple contaminants on honey bee health. Through informal discussions at the state and local levels, both new and established beekeepers are expressing interest in natural beekeeping methods.


Potential Contributions

This study suggests using capping wax (from known and trusted source) rather than using commercially available beeswax foundation is one method to help reduce in-colony pesticide exposure. Minimizing the amount and number of pesticides embedded in beeswax would help reduce the known detrimental synergistic effects (even at sublethal levels) on developing bee brood and ideally improve honey bee health and reduce colony loss. With so many agricultural crops dependent on pollination, we must make changes to stabilize and hopefully reverse the ongoing loss of pollinators.

Future Recommendations

Future research: Since beeswax foundation is universally contaminated, repeat study using beeswax comb obtained from honey bee colonies with no foundation present such as top bar hives.

Future training: demonstration (and hands-on workshop) of alternatives to commercially available beeswax foundation: preparing crosswiring of wooden frames for use as foundationless brood chamber frames, making foundation from beeswax cappings, using capping wax to coat plastic frames.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.