I'm led to believe that formic Acid is a reliable treatment against the varroa mite. Apparently it can enter the capped cells as a gas and destroy the mite on larvae as well as those on adult bees outwith the cells. I'm also told that beekeepers on the continent and in the USA use this product to great success. I was advised that Thornes sold a product as Mite Away II, which were prepared fromic acid pads that one simply placed on top of the brood frames. Thornes have ceased selling this product and do not vindicate the use of Formic acid as treatment citing it as harsh, dangerous to bee and beekeeper.
There are other suppliers of Formic acid who one has to notify of intended use and then you have to go about carefully diluting the acid correctly and hopefully treating your colonies, killing the mites and hopefully not the entire colony. I've also heard that the risk of Queen loss is higher using any of the acids.

I am so confused about which varroa treatment to use I think I'll sacrifice an entire season's flow and alternate between Apiguard and Apistan to try and get my varroa count to a tolerable level. I'm beginning to think that making up another colony and treating them both for Varroa all season to give them the best possible chance of overwintering is my best way forward. Perhaps using an Autumn treatment of Oxalic Acid trickle in the Autumn. Perhaps next year I will be able to reap some honey, having started with a mite reduced colony.

Good evening Neil

If you look under the Disease forum you will find a posting by Kate Atchley on 08 March 2007 where she says ...



Don't know if this info is still valid by worth a look ?

Thanks again found your reply on other posted topic.
Regards,
Neil

My formic acid treatment is now finished. That was 3 treatment of 60% formic acid at 2ml per frame. I had a double brood set up.

On completion there were no, yes NO, varroa on the sacrificial drone brood. Also there were upwards of 80 dead mites on the floor. None were spotted elsewhere and the bees appear relieved of their varroa burden.

There were a few drone brood casualties but the Queen survived and kept laying, workers prospered.

Now replaced my metal QE and varroa floor and split the colony into a nuc box and and one brood and supers on the main colony.

Fingers crossed the colony gets on with it and makes use of a Tilia flow.

p.s. I'd thoroughly recommend using formic acid, I have had better results using this than any of the pyrethroids and thymol. It penetrates the capped cells which annialates the varroa on brood. Brilliant.