Help Oxalic Acid.

[Blackcavebees]

Hey Dave, welcome to the forum

I used Oxalic by trickle for the first time last winter. Easy to do and if you have only a few hives a much cheaper solution. There are "home made" vaporizers made using a 12v batt and a glow plug from a diesel engine which work but the stuff (oxalic) is nasty stuff and could do you a lot of harm without proper safety equipment. So for me I'll be dribbling again this winter. Your local doctors or chemist should give you a syringe if you ask politely (they often ask what for and it's a lead in for me to sell some local honey!)

Not sure if everyone does this, but I dribbled with warm syrup so not to totally chill the cluster. Obviously not too warm but I used one of those cup warmer cover things to keep it warm before pulling some out with syringe. Also, the commercial vaporizers are slim enough at end to fit through entrance block whereas some homebrew efforts I've seen need entrance block removed - just a thought if you are thinking of making one.

[Blackcavebees]

Gavin, I think we have two posts going on here on same subject

Thanks. Did spot it last night but lost the internet for a while (found it again!). Welcome, Dave. G.

[Jon]

I bring along a flask of hot water to the apiary which I pour into a container. I stand the bottle of Oxalic in this before trickling so that I am not tipping a cold liquid over the bees.
The best temperature for trickling is a coldish day, 2-4 C when the bees will be tightly clustered.
If you apply Oxalic in mild conditions the bees won't be tightly clustered and they will occupy more seams which means that they will get a much higher dose of oxalic if you base the dosage on counting seams.

[gavin]

I'll be treating bees today, and showing anyone who turns up at the association apiary at 1pm. Trickle/dribble of course, so I have no experience to offer Dave. None of that namby-pamby warmed-up flasks stuff here - these are *Scottish* bees so they'll get it as it comes! The bees themselves will be cool (should be no brood), and the small volume per seam of bees will only temporarily change the temperature of the few bees hit by the dribble. They may already be at a temperature close to the inside of my car.

Might there be more brood than normal at this time of year? Really don't know. Not sure that some flying and a little pollen coming in means they're raising brood. Can anyone guarantee that in a month's time they'll be less likely to have brood?

Digging out brood before dribbling? That has to be very disruptive and there's no way I'd do that at this time of year. And as for sublimation being more efficient than trickling, I doubt that. I seem to recall published work that implies that it is slightly less efficient (in terms of % mites destroyed per treatment).

Trickling:

- fast and easy
- very little equipment needed (and it is light)
- you only treat the bees, not their furniture
- safe for the operator, wear gloves and take care not to splash in the eyes
- can just pour away spare solution on the ground
- can be scaled up to do large numbers using a sheep medication dispenser
- ideal time to check stores by looking down on frames (Bees at top? cells at top still with sealed stores? Heft it with roof off?)
- ideal time to put fondant on light colonies, straight on frames or better on QX (don't need it before now, about to start brood raising, you hope)

Sublimation:

- don't need to take roof off
- can repeat (apparently) but how do you know it needs it?
- needs equipment carried to your bees (car battery or source of heat as well as the vaporizer)
- requires fine particle face mask for anyone anywhere near (it is said there are records of beekeepers damaging themselves by inhaling oxalic)
- much of the oxalic acid lands on woodware and will remain there until the colony fills the box
- isn't well integrated with sorting winter stores issues
- folk say it is efficient for large numbers of colonies (but so is trickling)

Some LAs seem to go in for sublimation in a big way. Seems a big mistake to me to show novices a more dangerous way of treating your bees.

[prakel]

And as for sublimation being more efficient that trickling, I doubt that. I seem to recall published work that implies that it is slightly less efficient (in terms of % mites destroyed per treatment).

I spent a while this morning trying to find a link to some research that came from LASI earlier this year (which I'm sure does exist). I think that it even made it's way onto the BBC website and into assorted papers too at one point which rated sublimation very highly and no doubt it was those findings which were driving Karin Alton's thinking. The problem, is that for some reason I can't seem to find any mention, anywhere. No references are coming up after several different searches.

[prakel]

I spent a while this morning trying to find a link to some research that came from LASI earlier this year (which I'm sure does exist).

......

http://www.telegraph.co.uk/earth/wil...wrong-way.html

Now researchers have found that when applied as a vapour rather than a solution, and at a particular dosage, the treatment can remove virtually all traces of varroa from hives without any harmful outcomes for bees.......

Results from the trials have not been officially published, but Prof Francis Ratnieks told the Telegraph that in the most effective format – a vapour at a particular concentration – the treatment was 97 to 98 per cent effective.

Took a while to find, I seem to remember there was a fair bit of discussion on the net at the time but strangely that it almost all concentrated on the couple of almost throw away lines at the end referring to crossing with African bees.

[Daveoneflowers]

Hi, this is why I am so interested. Found out about it on an American site where it seemed very popular an effective. In America they sell a unit that looks a bit dangerous for 175 dollars. I'm going to try and design an effective safe unit. I don't feel I can completely give up on the idea. Your post was a gem.

[Jimbo]

I have experience of using both methods and in my opinion would forget the sublimation method. It is too much of a faff and on a health & safety point is far more dangerous to the operator due to the sublimation gas. The trickle method is cheaper and quick to do if you have to get around a number of hives. I usually trickle when the temperature is about 5 degrees and I don't warm the oxalic although it is not freezing cold either.