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Is this chalk brood? If so, please help 😔


Is it chalk brood or wax moth…? Or is this normal… ? It doesn’t look good at all…?
What do I need to do…? :pensive:


It’s chalk brood mummies.

How is your hive looking? Good numbers?
How did you acquire your bees?

How long has it been since you checked the bottom board? ie. How long did it take for this number to appear?


I got my bees in a nuc from someone from my bee club… he says they are Caucasian bees… the numbers are good… and the queen seems to be laying really well…

It has only been about 4 days since I checked… but about a week ago I moved the cork flute slider to the second run down as I didn’t think they were getting enough ventilation… and I’ve got a entrance reducer in there… so I’m assuming I didn’t move the cork flute slider down quick enough and they got a bit damp…? And I corked up the roof because there was a tiny bit of water getting in… or it was too cold when I moved my cork flute slider and they got cold and died.? We’ve had a couple of cold days and nights lately… like 6 degrees Celsius nights…?

Tomorrow I’m going to make the entrance a bit bigger to allow more ventilation… but I’m hoping by corking the roof and moving the cork flute slider down last week, it will allow more air in to dry them all out…?

Please advise if I did the right thing…?


Ventilation is over-fussed about. I use solid bottom boards and some of my hives have a 1" entrance at the bottom and top in 90f, direct sunlight temps. They do just fine and are productive.


The primary cause of chalkbrood is slightly chilled brood. It can’t germinate at normal brood nest temperatures. It will clear up on it’s own.


Try to keep the bottom board clear of mummies (ie. the mesh the bees walk on, not just the corflute sheet), and check regularly that the bottom of the hive is clean to prevent bees walking through/past them. Depending on how bad it is in the hive, you may also want to rotate combs out if they are full of mummies. You may also benefit from feeding the hive to build up strength/numbers if they start going backwards (the number you have shown doesn’t look too serious).

There is a good fact sheet on it here:

Ventilation is important if you currently have moisture in the hive, ie. the mummies are wet/sludge or the bottom board has water build up in the corners for eg. otherwise I wouldn’t be too concerned. As Melbourne regularly reaches 40c+, it’s something to keep an eye on coming into summer (also ensure there is ample water available).


Some good points made in this post, just remember that chalkbrood is a fungus and will remain as viable spores in and around your hive for decades to come, don’t share the contents of this hive with any of your other hives and likewise with your tools. This is probably your only hive so there is most likely nothing to be too concerned about infecting others. If the chalkbrood doesn’t clear up in the next couple of months then look to source a new queen. Jody Gerdts of Bee Scientifics is down your way and has been working on a hygienic bee to specifically combat chalkbrood.


Michael Bush is right. The growth of chalkbrood is due to low temperatures NOT lack of ventilation or dampness as is commonly touted. Sometimes the broodnest expends faster than the worker bees can cover it or there’s a cold spell in the spring when the bees are building up, or you opened the hive and kept it open too long when it was below 60F or at the end of the day when it’s harder for the bees to warm the brood back up. It’s the 3-5 day old larvae that are affected and turn to mummies after capping. The fact that there are some on the bottom indicates that at least some of the workers are hygienic, that is, they uncap the larvae and pull them out. Caucasians are notorious for chalkbrood and propolis, but are nice bees.
Chalkbrood is pretty much everywhere in the USA and probably in Australia too, but check with your bee scientists there. So, I don’t toss my frames unless the chalk gets really bad. If it does, cage your queen for a week, take out the worst frames and it should clear up. Screen bottom boards are useless except for ventilation in really hot weather 90F+. The queen won’t lay near them, they attract robbers and critters, including ants, and they just don’t last as long.
I think it’s getting warm down there. When it’s over 65F go out and get into your hive! This is the fun part!
Kristina Williams
Boulder, Colorado, USA


I am reading all the posts on chalkbrood and as I am reminded find a mentor but I honest l have tried and just am too rural and no beekeepers have time. So bare with me. We have had rain but an inch or so here and there nothing serious. Today sunny and I noticed my bees all over the place. In my kitchen and I went to look at hive bees all over. I opened the hive to see what was up and noticed dead bees and the med frames that I purchased were black and the comb was not there with which I thought fungus. I did not bring my camera but will open it again in the morning an take pictures as it was getting dark. This is my first hive. So without pictures and black color of the comb and it looked like it was sloughing off. Any ideas? I think they are diseased but not sure with what and how to handle.I pulled two frames and tomorrow will pull them all. The new deep bottom frame has one healthy deep frame from what I saw on my peak. I saw black comb and white stuff.


Hi Neuman, pictures will tell the story but black comb could just be a sign of an old hive. If you can see white grey larval mummies out the front of the hive and also in the cells of the comb then you more than likely have chalkbrood or stonebrood. If its AFB or EFB, this is a different story and its very important to diagnose the difference. If you think it could be AFB or EFB then a match stick to puncture a capped cell and swirl the stick in the cell and draw out the match to see if there is ropiness. Get back to us when you have had a good look.


Black and no comb doesn’t sound like chalk brood. But as you guessed, we can’t say for sure without a picture.

I have a hive that I was certain had one frame 50% with chalk brood earlier this week. We took it apart today - no chalk brood, no wax moth, no disease at all. Just a lot of healthy, somewhat annoyed bees. So we just closed up and moved on.

Not saying you don’t have chalk brood, you may well. Or heaven-forbid, AFB. But get pictures, and push a cocktail stick into any dark cells - if you get a big glob, that is worrying for AFB. We will try to help, whatever the result.


I will get photos. Thanks as I love my bees and they are very hard to get and are expensive. One thing was there were still a lot of bees in the box so I am hope full.


see nest post this would not load photos



The deep which is new and was healthy and the bottom. I have several more if you need.


There are several issues here. The frames you have photos of have been run with too wide frame spacing so they are ‘puffy’, the frame with foundationless comb on it looks to be largely drone comb. The other frames look like very old comb and lastly it looks like you have wax moth (the webbing between frames)

My first step would be to start cycling these frames out and cycling in new frames with wire and wax foundation. You need to build up a solid base for the hive.


Thank you for your reply. I did not see a queen and moved the frames out and to the side. Wax moth will have to study but as far as drone why is it turning black? I am lucky a friend has some frames and I am putting together now but no brood just wax so is the hive going to survive?


That looks like a classic “dead out” hive. The wax moth are doing their job beautifully. On the third photo, it looks like the frame on the right is slymed out with shb larvae. You need to clean everything up & start again with a fresh colony in the spring.


I guess if one could order bees but unfortunately none available basically begged for these and paid a premium. Not in my financial future. Pretty sick right now.


Any frame used for brood will turn black over time. Not necessarily a sign of disease. However, I agree with @RBK, you have a VERY heavy wax moth infestation there.

Not sure where you are, but SHB has been confirmed in Hawaii over 4 years ago. I don’t see any in your photo, but @JeffH has seen more of it that I have, and those maggots on the SBB could be SHB larvae.

Not sure that you need to do anything destructive, but I would at least freeze any frames you intend to keep for at least 48 hours. Better still would be to discard or render the comb, and start again with fresh frames. I understand that bees are hard to come by in Hawaii, but there are suppliers, and you will succeed if you keep trying. This company is on the big island, and even if they won’t supply you with bees (just queens), I am sure that they will know somebody who can.


Good luck, and so sorry that your hive didn’t do well.