Honey super mould and slugs

My super remained in place over a cold damp Ballarat winter, as it appeared to have some honey for the bees to feed on. When I opened the hive today the super frames were moisture laden, damp and almost wet and dripping. There was putty grey coloured burr comb in places, that looked decidedly unhealthy. Worse was the presence of quite a number of slugs, a few with their heads buried in the flow frame cells. I have removed the super and will clean it all up. My question is how has this come about? The hive appears to be weatherproof. Inside the lid there is fair bit of mottled mould and it is damp.

Hi Tony, the roofs are not weatherproof. Most people down your way remove the Flow supers during winter. I know that @Semaphore does & recommends removing it during winter.

The grey colored bur comb sounds typical of wax comb that’s been sitting in water for a while.

The good news is: it can all be cleaned up to look like new again.

Getting back to the roof. It can be made weatherproof with enough paint to seal the joins. Then you need to consider capillary action. You can run a bead of silicone (after painting) right around under the gables & overhang so as to stop water from running back into the inside of the roof.

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The moisture may not be the roofs fault. When the colony population isn’t big enough any supers not actively used are left to their devices by the bees. Over winter this means that supers above the colony increase in humidity.

I’d take the super off. Do what ever maintenance the woodware needs, including painting. I would then use a pressure cleaner, with warm water, to clean the flow frames.


Thanks Jeff. I have now pulled the flow frames out and they are black with mould in large areas so I guess that too suggests water leakage. I can’t quite believe how big of a job it will be to clean the fifty or so individual blades, in each frame, brushing the dirty wax from the plastic and putting them back together. Is there a design fault behind all this? You would think a roof should be weatherproof and I had earlier done the silicone trick. Appreciate your positive approach

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Hi @Tony1,
I would be more inclined to think that it was condensation as @AdamMaskew suggested rather than a leaky roof.
I believe it is best practice to always remove the flow super over winter in our cool southern climate.

You’re welcome Tony. I think that @AdamMaskew & @TimG are on the money as far as the condensation is concerned. The roofs do leak, so it would be easy to rule that out.

Get prepared to get wet while pressure cleaning the flow frames. @Semaphore warned me about that when I tried to pressure clean a customers flow frames after a hive beetle slime-out. He wasn’t wrong. Pressure cleaning, however would be much easier than pulling the flow frames apart like another customer did after she had a slime-out. Sounded like a real labor of love. If the first customer’s bees wont take to the flow frames (which still look fairly grubby & stained) after the slime-out, he intends on buying new ones.

I agree with all comments received on this question.

I’d also like to take the opportunity to highlight the importance of wintering, particularly in climates such as Victoria and Melbourne, for the survival of the colony. This generally means downsizing the hive to the relative number of boxes that intends to avoid harbouring empty space in the hive during times when the colony is not advancing but downsizing. See a cute little video on this here - How to pack down a Flow Hive for Winter in Victoria, Australia - YouTube

To help wrap a beginners head around the importance of wintering (I don’t mean to assume or point any fingers @Tony1, just flag the importance and take advantage of your question), the colony work really hard to thermoregulate the brood nest at 35°C, no matter what time of year, as the brood need to be this temperature to develop and can chill/die if the colony is unable to regulate this temperature for a certain period of time.

Empty, unused space, harbouring moisture and cold air in the super can seriously harm the colony and would have to be the most common reason for why beginners in Melbourne/Vic lose their colony’s do, in this part of the world.

Note other things that can trap moisture in the hive such as too-thick paint (3+ coats generally), which prevents the timber from being able to absorb any moisture and instead traps it in the hive.

For beekeepers in particularly wet or cold climates, consider if your hive gets adeqaute sun (5-6 hours a do, like a plant) and find a location that is away from moisture gathering things like a valley, thick bush or weeds etc.

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Hi we’ve got slime and slugs in the super too, mainly on outer two flow frames (next to the windows on each side).
Suspect we should have removed super for Winter.
Left it on as it had honey which I thought the bees might need. Honey has gone so perhaps this logic worked.
Inspected today and hive is healthy.
Cleaned slime & slugs out manually as far as possible.
Left lid off to try to dry flow frames in the sun - this mainly worked and now only slight damp and muckiness remains on rear cells of one frame only.
Will bees clean this up if it’s negligible?
Or do I have to pressure clean to eradicate immediately?
Can flow frames be run through a dishwasher?

Hi Bill, welcome to the forum. Whereabouts in Qld are you? I’m in Buderim.

I don’t think you’ll need to pressure clean the frames, I believe the bees will do that before they deposit honey in them. Other members like @Dawn_SD & @Eva might confirm this.

Definitely don’t put the Flow frames in the dishwasher. Another forum member (@busso from memory) had a bad experience by putting Flow frames in a dishwasher.

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Thanks very much Jeff, I appreciate your response.
I’m in Toowoomba where it gets very cold over Winter - definitely think I’ll remove super each autumn from now on.
I’ll see how we go with the slugs & slime (yuk!) as the girls are starting to head up into the Super now.
Interesting note - this time last year we were harvesting each frame in the flow super. This year there’s not a cell of honey in the hive yet!
It’s been too cold and damp I believe, but the bees are getting very busy now, so the honey should follow with any luck.

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Hi Bill and welcome!

UV exposure isn’t good for the plastic. I’m sure they’ll be okay this one time tho. Maybe try setting them up inside somewhere with a fan to get the last bit of moisture out to help avoid mold growth while in storage? Even if some does grow, it won’t be too big a deal - as Jeff said, no special cleaning is usually needed & the bees will deal with most all kinds of residue in the cells themselves.

People have had to take apart frames, use pressure washers, etc when there is excess propolis or cocoons left from brood rearing, that impede the proper opening and closing movement. You can do a lot to avoid those kinds of messes and the more involved cleaning they require by using metal queen excluders, and careful timing of supering and removing it before cold sets in :wink:


Thanks very much indeed Eva.
Good to know the synthetic comb doesn’t like direct sun.
Will send follow up post to advise how we went with all this, if I remember.

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