winter oxalic treatment

[psafloyd]

Default
Checked my varroa board after a week and found no mites. Yes, that's ZERO mites.

I know it is daft to worry about something I can do nothing about, but this lot were crawling last September and had a high mite drop after Apiguard.

I can't believe OA Could have removed 100% of mites, so coul it be the oil I treated my board with is not sticky enough? On checking,m it was still pretty slick with it, but I didn't have any Vaseline.

 

[RoofTops]

OA will at best kill about 95% of the mites.

I suspect your surviving mites are probably in sealed brood at the moment. They will be back!

 

[psafloyd]

OA will at best kill about 95% of the mites.

I suspect your surviving mites are probably in sealed brood at the moment. They will be back!

I don't doubt it. Couldn't believe zero for a week.

 

[The Drone Ranger]

Effect of Two cycles of oxalic evap on 22 hives

View attachment 4251

Stacked bar graph of effect on varroa population of 2 applications of oxalic acid evaporation

 

[For want of a better word]

Any statistics gurus out there?

Could use data to show variance between hives and treatments, and if prior treatment or not has skewed the outcome event of a zero varroa mite drop ?

Would there have been any other factors that could influence the result... temp.. pressure... sunspot activity.. length of daylight?

please do not get upperty... this is very interesting information... and I am not being critical about the information or presentation.... just wondering if the Apisan followed by oxalic acid gassing was more effective than either one treatment alone and if someone better at statistical number crunching than me could clarify the results?

 

[nemphlar]

formic acid

Only loosely connected to the current topic, but perhaps some of the contributors have experience of summer formic treatmentand can advise.
i've now applied 140ml/65% formic acid to 4 hives, used an insulated eke and appear to have had reasonably consistent evapouration over 8 days. I had expected to see lots of dead juvenile varroa on the sticky boards, but only the odd bee larvae and varroa adult. The queens are laying well.
This is a first attempt, how do you measure success or is this a sign of no affect?

 

[oliver90owner]

My first question would be: Why are you treating?

Second is: what is the present varroa loading.

I have used 70% in the past and it worked OK

RAB

 

[nemphlar]

Rather a long story but you did ask.
I started last winter with 8 young queens and 1 2nd year, well fed and hives full of bees, for the first time I used trickle OA instead of gas. I had one 3 frame hive lead by the 2nd year queen and 3 young queens with a handfull of bees, I was advised that this was nosema cerana and that the trickle had probably done for them. I fed them syrup laced with fumidil for three weeks and they seemed to recover, I've moved on to continually feeding the emulsified thymol version since May, checking drone comb found some varroa and decided to treat with formic acid and I'm intending using OA gas this winter. They are going well after the FA treatment.
If they dont survive this winter, I think that will be it.

 

[RoyCropper]

How long does Oxalic acid in solution remain effective?

Hi,

I bought some Oxalic acid last year already made up in solution. I still have most of it left. Will it still be effective this winter - 12 months after purchase?

Thanks

Roy

 

[Erichalfbee]

Has it a use by date?
If not then throw it away. Similarly if there is any discolouration.
Where have you stored it?
I have a bottle with "best by Dec 2012" on it. If I decide to use Oxalic in January I will use that bottle which,by the way, has been kept in the fridge since last year.

 

[itma]

Hi,

I bought some Oxalic acid last year already made up in solution. I still have most of it left. Will it still be effective this winter - 12 months after purchase?

Thanks

Roy

Roy its not a matter of the Oxalic's "effectiveness".

The reason for throwing it away is that it is used in syrup, and the acid acts on the syrup while in storage.
Specifically, chemicals called HMFs are formed which are toxic to the bees even at a low concentration.

Straight Oxalic Acid can be stored for ages.
But dilute solution made up in syrup, ready-to-use, has a VERY short shelf life. Only several months in the dark and cold of the fridge.
Dump the old stuff. Appropriately.
Its not worthwhile to take chances.

 

[RoyCropper]

Thanks for the replies Eric and Itma. The solution was made by my local association so it doesn't have a 'best before' date. I assumed the acid would be ok but wasn't sure about the sugar etc but Itma has put me straight on that. Best get some more from Thornes when I go to the sale.

Thanks


Roy

 

[Black Comb]

What about freezing? Does it still degrade?

 

[itma]

I doubt freezing would completely stop it.
But the stuff is so cheap as not to contemplate storing.
Even the Trickle2 bottle (for 2 hives) is under £3 from T's.

 

[Erichalfbee]

The reason for throwing it away is that it is used in syrup, and the acid acts on the syrup while in storage.

My bottle was bought in September last year. It has UBD of end Dec 2012 and "solution stable between 10˚ and 25˚"

 

[itma]

What about freezing? Does it still degrade?

My bottle was bought in September last year. It has UBD of end Dec 2012 and "solution stable between 10˚ and 25˚"

Dave Cushman's site quotes some Swiss research, concluding "... Therefore, we recommend as a precaution the use of freshly prepared solutions or solutions stored in a refrigerator. The solution can be stored during maximum 6 months at a storage temperature of 15°C."
http://www.dave-cushman.net/bee/oxalicstorage.html

It looks as though degradation at fridge and freezer temperatures should be negligible.
But being so cheap, why take a chance?

 

[alldigging]

Dave Cushman's site quotes some Swiss research, concluding "... Therefore, we recommend as a precaution the use of freshly prepared solutions or solutions stored in a refrigerator. The solution can be stored during maximum 6 months at a storage temperature of 15°C."
http://www.dave-cushman.net/bee/oxalicstorage.html

It looks as though degradation at fridge and freezer temperatures should be negligible.
But being so cheap, why take a chance?

If it's only going to be used in winter then it'd have expired by the time you want to use it again. And the idea of keeping something sweet and toxic in the fridge might not be the best idea.

 

[victor meldrew]

Aldi are doing a micro wavable heat keeper jar@ £3.99..
.5 litre, ideal for keeping oxalis acid warm, cheap enough to keep as a dedicated tool for varroa control. Complete washing plus clear labelling should cover safety aspects ?
VM

 

[For want of a better word]

I used a dispenser similar to this for offer on Flea Buy
Item number:110978624565

I had a plastic container with a beercan cover to keep contents warm and a bit of aquarium air line tube to direct the liquid between the frame gaps over the cluster .... still a 2 person operation if ( as it is) speed being of the essence !

 

[Varan]

Incidentally, that link to the late Dave Cushman's site is really great. Reminds me of what the internet was once, free, fun and educational.