What to do with moldy combs

A few years ago a beekeeper friend announced to me that mold had taken over her hives and killed all her bees. Now whenever I see mold—or even hear about it—I think about her. When I tried to explain that it was the other way around, that the bees died and then the mold came, she didn’t believe a word of it. She cut out all the combs and washed the frames with bleach. Too bad.

A variety of molds will grow on the combs when the moisture in the hive gets too high. The moisture gets too high when there are not enough bees to fan it away. I suppose the confusion arises because these moldy combs frequently contain dead bees that are also covered with mold, so it looks like the mold killed everything.

According to various sources, one of the molds frequently found on combs is Penicillium waksmanii which can actually inhibit the growth of certain bacteria, including American foulbrood. Other molds are usually present as well, as evidenced by the different colors—usually blue, white, yellow, or gray.

If you have a dead hive loaded with mold you will be tempted to discard the comb, but it is usually not necessary. The first thing you need to do is decide how the colony died or became weak. If you can eliminate American foulbrood and colony collapse disorder, then you can re-use the combs.

The first thing to do is take the frames to a warmish, dry place where they can dry out for a few days. These things can smell wicked—like moldy stuff does—so put them in a place where they won’t bother you. Separate any frames that are molded together and let them air dry. As they dry the mold growth will slow down and then stop.

Once the combs are dry you can store them in an empty super. After your colonies build up in the spring you can place the moldy super on top of a big, vigorous colony and the bees will clean and polish every cell in a matter of a few days. Worker bees always clean old cells prior to re-use anyway, so this is not an unnecessary burden on the bees. The bees are very thorough and, after they are done, the combs can be used for brood or honey production. It’s amazing, but no taste or smell of mold will remain on the combs.

Rusty

Comments

Scott Gibbons
Reply

Rusty, I will be installing a package shorty, and was wondering if I can use frames of honey to feed them from another hive that did not make it through the winter?

I have about six frames of capped honey (brood chamber sized frames) that I was thinking about using in lieu of sugar syrup to feed them if that is OK?

Was also wondering if I should feed them with an inner cover with a hole between two brood boxes to start, or to just add the second brood box with the honey frames right away or a couple of days later?

Thanks, Scott

Rusty
Reply

Scott,

If you are lucky enough to have frames of honey to feed a new colony, it is by far the better choice, as long as you’re confident the colony did not die of American foulbrood. AFB can be transmitted to a new colony through the honey, but other than that, you’re good to go. Whenever I start colonies on honey they build up fast and strong, which makes sense.

Forget the inner cover and put the box of honey on right away. Reduce the entrance to protect them from robbing, at least until they get established. Other colonies in the area may catch the scent of the honey, so give them just a small entrance to start.

Scott Gibbons
Reply

Thanks Rusty, I will follow your direction. Thanks for the call out on the entrance reducer as my neighbor has 3 hives up here in the West Hill in Auburn, WA.

Scott ;-)

Bonnie
Reply

Rusty, we have a hive that died this winter. I just opened it up and there is lots of capped honey, there were clusters of bees on several frames that had started to rot, (been dead for a bit) there was also a few in an area that looked like they just died. I am thinking the hive froze after reading your comments or lost the queen and the fresh ones could be from our other hive? I have bees ordered and would like to reuse the frames. How do I tell if they died of AFB?
thanks

Rusty
Reply

Bonnie,

First off, the hive will smell really, horribly bad. The smell will just about knock you over. Second, you do the ropiness test. You stick a matchstick in a dead brood cell, and when you pull it out it makes a long rope of goo. You can find directions here for diagnosing the disease: http://www.spc.int/lrd/ext/Disease_Manual_Final/b452__american_foulbrood.html. Based on your description, I’m guessing you do not have foulbrood.

Jay
Reply

Hello! I’m very new to the hobby and I just had some questions in regards to what to expect in the future. A lot of my concern is in regards to keeping bees from swarming due to being overcrowded. I’ve read various posts that said if your bees work from the bottom super up to the top one, you can place the top super back on the bottom and reuse the old super. That made sense until I read that bees will reuse their old comb? I was in the mindset that I would be washing/cleaning the old bottom super in order to be reused. In that mindset, there would be no overcrowding ever as long as you stayed on top of cleaning everything. But when I read that they reuse/fix their old combs now I’m confused. I understand that during honey flow, you put the top supers on so they can store their honey in. How would you go about making more room for the bees before they wanted to swarm? (Without having to buy many many extra supers to add on) I am starting with two deep 10 frame supers and 2 medium supers (for honey collection only) I live in New York State where the winters can be cold and snowfall abundant. Thank you for the info and advice! Greatly appreciated.

Rick van vliet
Reply

Thanks for a great thread. Lost a colony during a long, crappy, snowy spring in Minnesota. They were alive in mid-march, started feeding 1:1 syrup, but they died sometime in the last few weeks when we had lots of snow. Guessing that they went queenless and just couldn’t keep their numbers up. Moldy frames, but not the stink of AFB. I’ll look closely, but will probably dry out these frames and get them back into newly-packaged hives after a couple of weeks (packages installed 26 April).

Cherokeescot
Reply

The only way to be sure about the type of mold is to destroy the spores completely. That way you have no worries. Here, its a simple operation. Place a number of frames in a large plastic trash bag. Place an Ozonator inside the bags making sure none of the vents are blocked by frames or plastic and unable to suck in or discharge.

Leave in for two days on high or ‘away’ mode. This completely eliminates mold, virus and bacteria.

Rusty
Reply

…until the instant you remove them from the bag.

Rebecca
Reply

Rusty,
I’m just getting into beekeeping. I bought a ton of boxes, frames, etc at an auction. The frames all have old comb on them, and I don’t know how old it is. I don’t have any history on the hive. I know I’d be risking a disease, but I was wondering what your thoughts were on trying to reuse everything as is? Is there a time limit to how long combs can sit, then be reused? Is there anyway to tell if they’re too old? Also, reading one other post, if I use a super on the bottom for a brood box, then the bees move up into a smaller box, do I somehow have to get them back into the super in spring, or can I just take it for another set of bees and leave them the littler boxes? BTW-your info is fantastic. I’ve been searching everywhere and finally found several other answers right here. Thanks!

Rusty
Reply

The real problem with old equipment is American foulbrood. But if the comb doesn’t contain dead brood, it is probably just fine. So I would check it for dead brood and then make a decision. Bees prefer old comb, although if it hasn’t been used in a while, it probably no longer has the odor of bees. Old comb is more brittle than fresh comb, but that isn’t much of a problem either. There is no pull date on comb, so if it is not diseased it will do the job for you.

Generally, bees move up in the winter, down in the summer. They will get there on their own. If you want to speed things up, you can reverse brood boxes, but you don’t have to.

Alicia
Reply

This is a great post. Very useful since I lost both of my hives this past winter and had a bunch of perfectly good comb left. One smell I am curious about is dirty socks. This is a smell I get with some of the frames with uncapped nectar, and I don’t think it was the pollen?

I was also wondering if it was okay to use frames that have had wax moth droppings on them, but the moths themselves had been disposed of? On that same idea of pests another issue I was curious about was ants, cockroaches & earwigs. They have moved into the area where I had the cleaned out hives, and this is where I have my new hives…what is the best solution without affecting my new bees, or maybe I should restate is there a solution? I wasn’t sure if diatomaceous earth would be harmful to the bees if i spread it around the outside of the hive.

Rusty
Reply

Alicia,

Sometimes when you have uncapped honey, you get fermentation. That is probably what you are smelling.

Honey bees are clean freaks and a strong hive will be able to clean up insect frass, droppings, and live and dead bodies. They can do this much more efficiently and effectively than we can. The material from your cleaned-out hives will soon decompose into the soil. I wouldn’t worry about it.

Some people use diatomaceous earth around their hives. About the only bees that get into it are those that are already weakened and dying.

Julie
Reply

Rusty -

Wish I’d read your site before yesterday when I took apart the frames with mold on them. You say I could have used them (I know the hive died because it lost its queen and there were too few to keep the place warm). But some of the wax on the frames was so brittle. It just crumbled; not at all wax-like. Could those really have been used again? I can probably retrieve some from the trash (I broke them apart to make them fit my small bin – argh!), but I’m wondering if they really can be reused in such condition. Will the bees remove brittle wax?

Rusty
Reply

Julie,

Yes, the bees will fix them up. How cold was it when you were working with the frames? The wax is extremely brittle in cold weather but softens as the temperature rises. If the bees have preformed comb, it saves them a ton of work, even if they have to clean it up first and mend it. Exuding all that wax requires much energy and therefore much foraging just to make comb. A colony on preformed comb gets a huge head start in the spring and will be able to store much more honey over the course of the year. One thing I learned early on is that drawn comb is the beekeepers most valuable asset.

You shouldn’t worry about the brittleness; that’s for the bees to worry about and they will know how to handle it. As for cleaning moldy combs, it only takes a day or two to get everything cleaned up and shipshape.

I do think, however, that old black combs should be replaced every four or five years, a few at a time.

Lisa
Reply

Hey Rusty,
I am a newbee that lost a hive over the winter – I think something mysterious happened to the queen and they died out. There was a lot of honey left, no dead brood, no dead bees but maybe a dozen or so when we first opened it up. We are extracting the left honey as I type – we are moving out of state and will be gifting our hive and frames to the local beekeeping club, but wanted to eat and give away some of the honey. There appears to be black mold over the comb in places. Is this okay to eat? It is honestly hard to tell if it is mold or just debris if the bee variety. An experienced beekeeper with our association came to look at the hive while we weren’t around but he passed a message along agreeing that he thinks something happened to the queen and seemed fine with loaning us the extractor, so I am assuming there is nothing to be concerned about. Just being new to this, I thought I would pick your brain. I tend to err on the side of eating things if they seem moldy anyways but this is a new world for me. Just want to be sure there isn’t something freaky I might be eating or sharing with loved ones. Thanks!

Rusty
Reply

Lisa,

I think it will be just fine, especially since you are extracting it anyway.

terri
Reply

Hi Rusty!

I have a new hive that had fresh foundation in the frames. On one, the cut comb sheet must have broken and the bees are building wacky comb on it which looks like a rolling wave with cells built under the crest and on top of it. It still fits together with the other frames and it has brood in the cells. Can I leave it as is, or should I take it out and replace with fresh foundation?

Rusty
Reply

Terri,

I would just leave it. Things like that happen all the time.

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