Sterilising Combs

[Jon]

Put the combs in a sealed container such as a plastic storage box with a tight fitting lid.
Place a container with about 75ml of acetic acid on top.
The fumes are heavier than air and will fill the plastic storage box.
leave for at least a week.
You are supposed to air the frames for a day before use but I have put frames straight into a colony on occasion without any negative reaction. They smell like vinegar.

You can also do it by making a stack of brood boxes and putting the acetic acid at the top inside an eke.
They need to be well sealed or inside a large plastic binbag.

[gavin]

Hi Bridget

Yes, super comb I wouldn't fumigate - unless I had an active EFB outbreak, then I might do it. Brood combs? Maybe a third each year, trying to end the year with the dirtier combs towards the outside of the brood box and so able to be reclaimed before the colony builds up again. Or a whole box once every 3 years or so after doing a Bailey comb change.

I often destroy the frames (nice wee bonfire) but perhaps I should recover the wax instead in a melter. If the comb is in good condition I will sterilise then use it again for bait boxes or to help nucs build up. Before sterilising the empty brood frames I pick off any sealed cells remaining on the comb. Then they go in a brood box, get a kitchen sponge with ~50ml of acetic acid (80%) placed on the top bars, the the whole thing goes into a bin bag (tied or otherwise sealed) to sit in the sun.

[Black Comb]

I see varying amounts recommended per box. Jon uses 75ml, Gavin 50ml.
Nub leaflet recommends 150ml per box.
BTW, NBU downloads are free and a very good source of disease information.

[Jon]

I find it hasn't even all evaporated after a couple of weeks so I reckon the lower quantities are ok.

[gavin]

I see varying amounts recommended per box. Jon uses 75ml, Gavin 50ml.
Nub leaflet recommends 150ml per box.
BTW, NBU downloads are free and a very good source of disease information.

Gavin should have kept his mouth shut/fingers still. He can't remember what he uses but has to go and look it up every time.

[Jon]

It also depends on the size of the box, how well sealed it is and the rate of evaporation.
Some of the recommendations refer to a stack of several brood boxes.
The plastic box I am using at the moment has a similar capacity to a brood box.

[The Drone Ranger]

Acetic is a menace for eating frame nails etc. I have read that just 1/2 hour or so is long enough
If it's just for nosema spores on brood frames apparently UV light is enough so perhaps one of the ones sold for fish tanks might be adapted

[Jon]

The recommendation is that frames are fumigated with 80% acetic for 8-10 days.
I think the nosema spores are very susceptible so maybe they are killed off quite quickly as opposed to any of the other stuff.
Freezing for 48 hours is another way to kill nosema spores.

The acetic acid does oxidise any exposed metal but not enough to make things fall apart.
If you have metal frame runners you can cover them with gaffer tape or vaseline.
Same for any nails you are worried about

[gavin]

Acetic is a menace for eating frame nails etc. I have read that just 1/2 hour or so is long enough
If it's just for nosema spores on brood frames apparently UV light is enough so perhaps one of the ones sold for fish tanks might be adapted

The benefits are several. Nosema, chalkbrood, viruses, probably even EFB - low levels, subclinical, largely disposed of. So I would always give them the week OK (the 8-10 days), longer if the sun wasn't out much that week. I've done this a few times and never noticed much effect on frame nails, wires and runners. If the box is dry at the same time I don't think that much happens. Maybe doing it in the warmer weather is wise, choosing that window between the start of spring and the start of the swarming season.

[Jon]

The worst effect I see is where you have a frame only partly drawn out.
The acid fumes oxidise the wire where it is part embedded in the foundation.

I have no idea how effective this is but it is inexpensive and relatively straightforward to treat large numbers of frames by making a stack inside something well sealed such as a large plastic binbag.

At this time of year a lot of beekeepers have spare comb from deadouts or from taking off excess stores so it is a good opportunity to reduce the pathogen load on the comb.
Some commercial beekeepers irradiate comb but I think this is only economic if done on a very large scale.