Oxalic acid sublimation frequency

Not sure about this, but a couple of articles I have read suggest that although trickling oxalic acid/sugar should be done only once a year, sublimation by heating powder can be done several times. Have I got this correct and anyone else tried it? I ask because a couple of my colonies have not yet had any varroa treatment and I was thinking of treating in this way now and again in January.

Read Hivemakers posts on sublimation.

He has it well documented.

Stick to the five day cycle, repeated a further twice. Any other sublimation treatment regime with brood present is a waste of time - think here why the five day cycle and frequency get the results and it is clear an simple why it is done that specific way.

RAB

oliver90owner said:

Stick to the five day cycle, repeated a further twice.

RAB

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Assuming the treatment kills most effectively for the first 48hrs after treatment, and emerging varroa take at least 4 days to jump back into bee brood - on day8 or9 after the egg is played - my maths make the most effective three treatment regime when brood is present to be the second treatment to be 6 days after the first and the third and last treatment to be 16 or 17 days after the first to expose each and every varroa to th treatment while in the phoretic stage.

I shall try it. Thanks. I didn't find Hivemaker's post though.

So am I correct in deducting that it is this simple, as follows

Day 1 - first treatment treat
Day 6 - second treatment
Day 16 or 17 - the third and last treatment

Jimy Dee said:

So am I correct in deducting that it is this simple, as follows

Day 1 - first treatment treat
Day 6 - second treatment
Day 16 or 17 - the third and last treatment

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Yes Jim ... but you need to do it properly .. ie: hive sealed ... and don't sniff the fumes !

Phil

Jimy Dee said:

So am I correct in deducting that it is this simple, as follows

Day 1 - first treatment treat
Day 6 - second treatment
Day 16 or 17 - the third and last treatment

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Think so. That's what I wrote down in my little beekeeping treatment recipes folder.

pargyle said:

Yes Jim ... but you need to do it properly .. ie: hive sealed ... and don't sniff the fumes !

Phil

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Don't sniff the fumes is apparently about right, but I do use a respirator and I stand upwind

Jimy Dee said:

So am I correct in deducting that it is this simple, as follows

Day 1 - first treatment treat
Day 6 - second treatment
Day 16 or 17 - the third and last treatment

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Erm...., it's a work in progress.
Looking at it again, from ~day12 to day 16 there will still be mites diving in to hide and breed, perhaps the recommended 5 day interval is betterer after all, but essentially clean brood from the first treatment will take 16 days to emerge( varroa jump in at day ~8 from egg + another 16 days to emerge- for drone brood that is, egg to bee=24 days), perhaps 4 doses at 4 day intervals would catch the buggers, brains not clear at the mo

totally confused now mbc. I think I'll go for a sniff of the fumes - I generally see clarity after a good lung full !

so is it every 4 days for 4 turns ??

mbc said:

Assuming the treatment kills most effectively for the first 48hrs after treatment, and emerging varroa take at least 4 days to jump back into bee brood - on day8 or9 after the egg is played - my maths make the most effective three treatment regime when brood is present to be the second treatment to be 6 days after the first and the third and last treatment to be 16 or 17 days after the first to expose each and every varroa to th treatment while in the phoretic stage.

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Not sure I agree with your logic. Take the simpler case of only worker brood. A generation of brood (and mites) would have been sealed during your first and second treatments. Emerging on day 9, say, the next generation of mites could be sealed back into brood cells by day 16 or 17.

Hivemaker suggested 3 treatments, at 5 day intervals, if I recall. If worker brood could be sealed 12 days, would 6 or 7 day intervals cover that better?

Jimy Dee said:

so is it every 4 days for 4 turns ??

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But then most varroa spend at least four days out before embedding again (or for the first time), add 48hrs for the most bang for your buck with the oxalic acid and your at a six day interval, divide 16 by 3 and you get 5 and a bit, seems about right on reflection, I think I may need a pull on a smoke to clarify matters!!

alanf said:

Not sure I agree with your logic. Take the simpler case of only worker brood. A generation of brood (and mites) would have been sealed during your first and second treatments. Emerging on day 9, say, the next generation of mites could be sealed back into brood cells by day 16 or 17.

Hivemaker suggested 3 treatments, at 5 day intervals, if I recall. If worker brood could be sealed 12 days, would 6 or 7 day intervals cover that better?

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I'm assuming mites are emerging all the time, exposed for four days ish, then safe again once they sink into brood food ~ a day and a half before the cell is capped. Catching them sometime in the assumed 48 hrs of maximum effectiveness of the acid when they're exposed for four daysish shouldn't be too much of a mathematical problem, but I'm afraid it's too much for me at the moment.
Do you agree with the assumptions? That would be a good place to start.

Jimy Dee said:

totally confused now mbc. I think I'll go for a sniff of the fumes - I generally see clarity after a good lung full !

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Totally confused ? Most beekeepers spend most of their time like this .. why should you be the exception ...

MBC is right ... if you want to get the maximum effect from OA vapourisation then you have to do it at intervals that will catch the mites that are in the cells when you do the first treatment. Then you have to factor in the fact that some of the mites will emerge in the period after the first treatment but before the second ... and some of these could then be back in the cells and breeding when you do the second vapourisation.. The situation becomes even more complex when you are doing the third treatment ...

So ... the ideal situation would be when there is no brood present and the temperature outside is less than 5 degrees so that few bees are flying .. but - you really don't want the bees to be clustered as the treatment works by the OA being spread throughout the hive and the bees (and phoretic mites) coming into contact with the sublimated OA. If they are clustered then the treatment will not be as effective.

Therefore, your parameters of treatment (ideally) need to be a day when it is cooler and when the bees are not flying, when there is only a small amount of brood present and then to carry out treatment three or four times at intervals of between 5 and 8 days in order to 'catch' the mite's reproductive cycle and take into account the fact, that if the queen is still laying then the brood cycle of the drones (and/or worker bees) will also need to be factored in ...

Confused ... clear as the mud on yer boots !

You will probably need a pencil and paper and a fair bit of thought ... glad I'm not doing it !! But ... as varroa treatments go ... and as a non-treater .. I reckon that, done correctly, it is the least damaging to the colony and the most effective in terms of mite knock down - it's also one of the cheapest if you make your own sublimation kit. Just be careful as (you well know) it's not nice stuff to mess with !

Heinz Kaemmerer of Heilyser Technology Ltd. says: “With brood, colonies can be treated with the right amount of OA 3 to 4 times, a week apart; there is no harm to bees, queen or brood.”

7 days is an appropriate frequency for application. The calculations being expressed in this thread are not taking into account the persistence of the sublimated crystals - which will remain effective for a couple of days after each application.

LJ

Why don't you all on sit down quietly and draw a time line?

Not much drone brood around at this time of the year - and if there is, the colony likely has greater problems looming.

Covering the worker brood cycle at this time of the year seems more than adequate. Most colonies really suffering with varroa are likely at the stage where drone brood is much reduced before the average beek even notices there is a problem. Removing most of the mites is the best we can do with any treatment - anyone who wants to kill every last one, every time, will be disappointed.

Regarding bees clustered or not - fairly immaterial. Pick your time of day if worried about flying bees. Always a simple answer to a simple problem if only you think about it. But even the experienced among us can very effectively muddy the water, it seems.

Personally I don't think I'd bother with treatment with oav when there's brood, but nevertheless an interesting exercise in thinking about various biology and time intervals. Those assumptions seem there or thereabouts according to what I could find on tinternet, and of course, barring the effective timescale of the oav, applicable to other treatments too.

oliver90owner said:

But even the experienced among us can very effectively muddy the water, it seems.

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Not like you to advocate blindly following advice without exploring the reasons behind it.

little_john said:

The calculations being expressed in this thread are not taking into account the persistence of the sublimated crystals - which will remain effective for a couple of days after each application.

LJ

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Ahem,,,,"48 hrs of maximum effectiveness of the acid"