I have used this varroa product on a hive myself and admit to overdosing the measure from a 500 ml bottle – the bees survived and I didn’t have a mite problem in the hive either!
It’s main active constituent is oxalic acid but in a measured dose with other ingredients which can be applied without damaging brood or contaminating honey. The BeeVital website has some interesting research documents supporting the case for the product. I like the fact that 15 ml measured ‘sticks’ are available making application easy.
In my opinion this is worth a try.
This is personal post by the webmaster and is not an endorsement by Pembrokeshire Beekeepers Association.