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 

12 thoughts on “Brood Comb Management and Treatment of Dead Outs: National Management Survey 2011-2012

  1. I find that the writer of this survey has a difficult to read writing style. I have to reread several times to understand.
    I feel like I am listening to Yoda.
    Thank you.

    • Thank you for your comments Kenneth. We realized that the results can sometime be difficult to explain and we will try harder to make the explanations easier to understand. We agree that we can improve on this writing style and will try to address this in the future.

  2. Your conclusions about the advisability of reusing old brood comb are the exact opposite of your data. Very confusing!

  3. O.K. … so it looks like if we replace old combs we will loose more colonies over winter, right? As an experiment I have started colonies from packages on foundation and still lost them over winter. So what’s the answer? When I replace winter losses with purchased nucs the combs I get in those $125.00 nuc are often pure crap. There doesn’t seem to be any way out.

    • Hi Robert, yes, we agree that it seems confusing and not intuitive. Remember, this is from survey results and NOT from a scientific study. Should we continue to get similar results over 3 years, we will conduct a study to see what the driving reason is behind the comb replacement. Also remember that we found that beekeepers who reported replacing >50% of old brood comb who lost more colonies; however, beekeepers who reported replacing less did not see any significant difference in mortality. For nucs, you may want to try replacing only a few frames at a time and for packages, you may want to consider using some old comb for them to begin on and add new comb as they grow. Thank you for your comment.

  4. I agree with Kenneth and Stephen. I am going to continue using old comb by stacking the deadouts on my other hives, feeding them and making splits. Please confirm your findings and rewrite this article to help all of us keep more bees alive. Thanks, Larry

  5. I should have watched your video before I posted my 1st reply. Dennis thank you for the video it cleared up my confusion! Larry

  6. Hi All, I agree things were confusing, but we made some edits and I think it is more clear now. The way the comb reuse question was posed makes the Yes respondents the ones that Did NOT reuse brood comb.

  7. Pingback: Comb Rotation | Sideline Beekeeping

  8. Did not reuse brood comb = Yes
    Sure sounds like a double negative. I think this chart, although it’s message seems simple, could be worded or presented better. Like “Did reuse brood comb” and “Used new comb”?
    Or “Did” and “Did not” – A chart should illustrate a concept not make it harder to understand. Just my two cents.

  9. If, in the Brood Comb Treatment chart, the percentage numbers on the left show mortality, as they seem to, then the blue columns (“using this technique”) can only be interpreted as follows: Irradiation causes the most mortality, followed by fumigation, then PDCB crystals, then culling, then freezing. that is not saying much for all these fancy treatments, don’t you think?
    Also, my understanding” of “culling” is that your do NOT reuse those combs, so how can that be worse than “freezing”? Did you assume that straight foundation was run, then?
    I do get rid of very dark brood comb, but I give my new packages previous *honey* combs sometimes with some honey still there. I can do that since I run only mediums: All combs are interchangeable that way.
    So, I get them started fresh with as much clean combs as possible. So yes, I did reuse, but no, it was not *brood* combs. Your survey, I think should make that distinction in the future. (I just hope I did not skew your survey with my 5 hives. chuckles, chuckles)

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