LASI oxalic acid sublimation

[Ammerbee]

I vaped at the end of august 3 times and was advised to do so again just before Christmas - thereafter I was advised to vape again a further three times from today (one treatment every 5 days) does this feel right?
thanks

 

[Erichalfbee]

What have the drops been?
If insignificant with the last vape leave alone. If significant and there is brood then you need to repeat

 

[Ammerbee]

right - thanks

 

[Eyeman]

If insignificant with the last vape leave alone. If significant and there is brood then you need to repeat

Hi Erica
Any guide to what numbers are significant
in a full size colony this time of year?

 

[Erichalfbee]

If there is no brood then if I had a drop of less than 50 over the five days I would leave it at that.
Any more and I would go again. I would repeat if there was brood and no I wouldn't open the colony. I can make an educated guess from inspecting the varroa tray and looking at the weather history and noting the time of year when the colony has no brood. For me the window has closed

 

[midnight sun]

https://www.youtube.com/watch?v=aMYx_YT302o

For those not on FB.

The battery of that size should last for a good few hives and have enough to start a jumbo jet! I prefer a 'lighter' bettery myself.

 

[madasafish]

If there is no brood then if I had a drop of less than 50 over the five days I would leave it at that.
Any more and I would go again. I would repeat if there was brood and no I wouldn't open the colony. I can make an educated guess from inspecting the varroa tray and looking at the weather history and noting the time of year when the colony has no brood. For me the window has closed

An IR thermometer applied to the crownboard# gives you a pretty good clue.
I weighed and tested temperatures on 26th December 2016 . Lang #8 had a temperature of 15.2C - all the rest varied from 7.1 to 13.3C...so I'll have to give the higher temperature colonies another dose as they likely had brood when vaped. Ambient at the time was 7C and it was sunny and calm.

# Must be taken quickly after the cover/roof is removed as it will cool very quickly. Or heat up in sunlight.

(None of this is rocket science - I am surprised hives were opened to test for brood)

 

[Erichalfbee]

Yes that's very interesting....especially the actual temperatures you got. Thanks madasafish

I'm in touch with a friend in The States who has an Arnia system in one of her hives(including the scales.......she has pots of money) and she is very pleased with the information it gathers.

Didn't somebody here on the forum invest in one?

 

[Brigsy]

I've just started with a brood minder . Cheaper option.

 

[Brigsy]

I am having some teething problems and will report properly when I have resolved them.

 

[Eyeman]

After 3 vapes 5-7 days apart still getting a couple of hundred mites 1 week after the last treatment.
Plan to retreat mid Jan all hives which still showed a high drop.
Bottom right corner shows OA crystals which condensed on the OMF

 

[charlievictorbravo]

After 3 vapes 5-7 days apart still getting a couple of hundred mites 1 week after the last treatment.
Plan to retreat mid Jan all hives which still showed a high drop.
Bottom right corner shows OA crystals which condensed on the OMF
View attachment 13857

For the avoidance of doubt, are you getting a couple of hundred mites PER DAY, one week after the last treatment or couple of hundred mites OVER ONE WEEK, one week after the last treatment? Even if it's over the week, it's still 30 a day, which is too high. If it's over a day, that's massive!

I had the a similar situation in the late summer last year when I was getting a daily drop of over 30 after 3 vapings. I did a 4th vaping 11 days after the 3rd and had drops of 489 and 195 in the two days after. Eventually (2 weeks later) the drop was satisfactory but then started creeping up again so I used a Thymol product to do an Autumn treatment that brought consistently low drops (1 a day currently).

This a long-winded way of saying continue with the vaping - my experience and that of others suggests that the bees can withstand repetitive vapings without undue problems. I read somewhere that LASI is researching repeated vapings with brood present so we might get some academic guidance on this soon.

 

[Beefriendly]

After 3 vapes 5-7 days apart still getting a couple of hundred mites 1 week after the last treatment.
Plan to retreat mid Jan all hives which still showed a high drop.
Bottom right corner shows OA crystals which condensed on the OMF
View attachment 13857

You might want to read a post I just made on the sublimation vs trickling thread. That amount of condensed OA on your open mesh floor strongly suggests your bees are not getting the optimal amount of OA vapour to get a 97% kill rate. Which may perhaps go some way to explaining why you're not killing them.
With that level of drops after 3 vapes you still have 1000's of varroa. You should expect to find after 48-72 post vape your board covered with perhaps up to or over a 1000 varroa mites if your sublimation is effective.

One of my badly affected hives dropped between 500-750 mites within 48 hours. 5 days later the same, 5 days after that less than a 100, final vape dropped about 10. That was September. Drop counts of varroa per week at present are averaging 1 (one) from that hive and I'm not picking up anything dropping in several of my other hives.

 

[Hivemaker.]

That amount of condensed OA on your open mesh floor strongly suggests your bees are not getting the optimal amount of OA vapour to get a 97% kill rate.

Indeed, and even with solid floors I found treating from the bottom of the hive to be less effective than treating from the top.

 

[Beefriendly]

Indeed, and even with solid floors I found treating from the bottom of the hive to be less effective than treating from the top.

Most beekeepers seem to use the cheaper 12v passive vaporizers which I think will make it more difficult to treat from the top, although I'm simply guessing as I don't use them. I use a sublimox active one and find top treatment is ideal and is the way I now treat my colonies. Winter excepted, but then I find I rarely need to winter treat as the autumn treatment has been so successful.....usually .

 

[REDWOOD]

I would suggest putting a couple of matchstick under the crown board next time you do it so the vapours get to the top of the hive. Or if you use feeder boards blanked off then create a small gap by sliding the blanks over a bit. Or use a bit of mesh.

 

[Beefriendly]

I would suggest putting a couple of matchstick under the crown board next time you do it so the vapours get to the top of the hive. Or if you use feeder boards blanked off then create a small gap by sliding the blanks over a bit. Or use a bit of mesh.

Not a bad idea. But if, say 1/3 (a guess), of your 2.25gms of vaporized OA is condensing on the open mesh floor it will be a lower concentration of OA vapour that the bees receive. Not enough to give a 97% kill rate as LASI demonstrated with a a full 2.25g/hive. I'm just speculating that this may possibly be the reason why so many divergent results are being claimed for vaping by different people. It seems to work well for some not others. I think perhaps the techniques of application could do with being thought about a bit more.

 

[Erichalfbee]

I would suggest putting a couple of matchstick under the crown board next time you do it so the vapours get to the top of the hive. Or if you use feeder boards blanked off then create a small gap by sliding the blanks over a bit. Or use a bit of mesh.

I open the crown board at one corner by slipping a hive tool in. I refuse to use matchsticks!
I use 3.5g "Apibioxal"...for each colony under the OMF

 

[REDWOOD]

I must say I use a hive tool also but I thought a little revival of the humble matchstick might raise a few eyebrows [emoji4]


Sent from my iPad using Tapatalk Pro

 

[Eyeman]

Thanks for the feedback
It was a couple of hundred after 1 week.
Technique the same for all my colonies: 19 full size hives and 24 nucs.
Observed the vapours rising to the perspex crown board before exiting through gaps in the entrance after 1.5 min of passive vape under the OMF, can't see the vapours not rising and circulating with the passive vape
I suspect some colonies still have a significant amount of sealed brood judging by the debris on the floor.
Will be vaping those high dropper a few more times.
Thanks