Brood Comb Management and Treatment of Dead Outs: National Management Survey 2011-2012

The way comb in bee hives are replaced and treated may effect the health of the hive. This summary report from the 2012 National Winter Loss and Management Survey relates brood comb management techniques to reported winter losses.

Replacement of combs in existing colonies is often recommended to remove the buildup of pesticides and pathogens in combs. The survey found that beekeepers who replaced 50% or more of the comb in their colonies lost more colonies than those who did not replace any suggesting there may be an upper limit to the amount of comb replacement that is desirable.

Another management strategy relating to brood combs, is the reuse of old combs from either dead colonies or purchased colonies. The survey found that beekeepers who reported that they did reuse old comb lost on average 4.7 more colonies per 100 managed colonies than those who did not reuse old comb. This agrees with the understanding that moving around old combs can put colonies at risk.

Brood Comb Management

comb replacement

Comb replacement is often recommended to beekeepers because pathogens, pesticides, and other chemicals can build up in the wax potentially affecting colony health. Beekeepers where asked, on average, how many frames from the brood area they replaced in the last year (0%, 10%, 20%, 25-50%, >50%, Figure 1). Beekeepers who replaced 50% or more of the comb in their colonies lost significantly more colonies (30.7% loss) than those who did not replace any, or 10% of the combs in their brood chambers (22% and 21% respectively). There was some difference based on region. Beekeepers in northern states who replaced 50% or more of the comb in their colonies lost on average 10 more colonies per hundred than those who did not replace any of the combs in their brood chambers. The same comparison was not significant when only looking at southern states.

combreplacementFigure 1: Winter losses reported by beekeepers with varying degrees of brood comb replacement.

This survey was not meant to determine the cause of differences, so we cannot comment on the reason those replacing no or few comb lost fewer colonies overwinter than those who replaced 50% or more of their colonies frames.

Brood comb Reuse

When colonies die or when brood combs are otherwise taken out of production, beekeepers typically reuse the combs from those colonies because new colonies can grow very quickly in combs that have already been constructed. Plus, new combs normally require new frames which is an added expense. Beekeepers were asked if they re-used brood combs that were either previously taken out of production or purchased. They were also asked about any treatments or culling of the combs done prior to reintroducing them to colonies.

In both northern and southern states , beekeepers who reported reusing old brood comb in their colonies reported losing more colonies than those who did not. Beekeepers who reported that they reused comb lost on average 4.7 more colonies per 100 managed colonies than those who did not reuse old comb. In other words, beekeepers who did reuse old brood comb lost an average 18.4% more colonies than beekeepers who did not reuse old comb, see Figure 2.

broodcombresuseNewHeaderFigure 2: Winter losses for beekeepers who reported reusing old brood comb in their colonies compared to beekeepers who did not report reusing brood comb.

Responses about treatments of comb before reuse included: culling, freezing, fumigating with acetic acid , irradiating, and using PDCB crystals. No significant differences in losses were found when examining these answers. Few beekeepers reported irradiation (22) and fumigation (20) of combs before reuse. We did not collect data on what proportion of the colonies within operations received reused combs, nor did we collect data on why beekeepers re-used comb. Conclusions about causation cannot be made from these reports. It could be that beekeepers whom lost more colonies had more comb to reuse, or it could be that reusing old brood comb puts colonies at risk. Neither conclusion can be made from this survey.

Treatment of Dead Outs

When a colony dies beekeepers can choose to use the equipment immediately or store the equipment for future use. Beekeepers who did not report storing their used equipment saw 14.6 fewer overwintered colonies lost per 100 managed colonies, or an average of 40.6% less than those that reported not using equipment.

The best way to start or obtain a new colony was by splitting. Which showed significantly lower mortality rate than alternative methods.

newcolonyFigure 3: Average winter colony mortality suffered by beekeepers who reported different methods for starting a new colony between April 2011 and March 2012.


This information is for educational purposes only. References to commercial products or trade names do not imply endorsement by the Bee Informed Partnership or its members. The results presented here are the summary of the population who responded. The sample may not be representative of the beekeeping population at large. These results simply highlight differences in the sample population. The results cannot be considered conclusive, causative, protective, or attest to product efficacy or lack of efficacy


Management Survey 2011 – 2012

How average losses were calculated and presented  |  Watch a vlog here

Appendix Items

Download the complete reports in the list below

Comb Management

Treatment of Dead Outs and Colony Replacement

All survey reports listed here: Bee Informed National Management Survey 2011-2012 

Written By: The Bee Informed Team

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The Bee Informed Partnership is a collaboration of efforts across the country from some of the leading research labs and universities in agriculture and science to better understand honey bee declines in the United States. Supported by the United States Department of Agriculture and the National Institute of Food and Agriculture, we’re working with beekeepers to better understand how we can keep healthier bees. The key to our success is the true partnership we maintain across a wide range of disciplines including traditional honey bee science, economics, statistics, and medical research that makes all these tools available to this important research. And just as important as the tools are the people. We not only have the leading researchers in the honey bee industry, we also have advisory boards from the commercial beekeeping industries, almond and other commercial growers, as well as naturalists and conservationists from across the country.