Varroxal and more midseason miticides — part 2

To paraphrase Harold Wilson, “a month is a long time in beekeeping”.

My original plan for part 2 of these posts {{1}} on “Midseason miticide musings” was to discuss some specific opportunities for mite control, the limitations (on exploiting them) imposed by the currently available miticides, the rules that control their use, and their mode of action.

But, in the intervening period, a new/old miticide, trade name Varroxal, has become available in the UK.

This has a different set of restrictions on its use (from functionally similar products), both in terms of approved methods and frequencies of application.

Varroxal is both new and old because it is pure oxalic acid (OA), or — more accurately — the dihydrate form of oxalic acid.

This is what beekeepers have had been using for at least three decades to control Varroa. However, in 2015, Api-Bioxal was licensed and generic OA was 'outlawed' (my understanding is that it had never been approved, but that its use was tolerated as a 'hive cleaner'). The introduction of Api-Bioxal brought with it new restrictions on the method and frequency of application, and the — functionally unnecessary? — inclusion of glucose which really messed up vaporisers.

More recently, generic OA powder was added to the poisons and explosive precursors list of “naughty stuff you'd be unwise to try to buy without a very good reason — and a licence” (since this is listed on the governments website under counter-terrorism it's probably wise to avoid falling foul of the regulations if you possibly can).

Although this situation still applies, the availability of Varroxal means that beekeepers can again purchase and use OA legally {{2}}, and can use it in vaporisers without spending an hour cleaning the burnt caramel from the machine.

So, in a change to the planned order of the post, I'll first discuss Varroxal (there are some significant differences to Api-Bioxal), before more musings about how — and importantly when — it, or other miticides, could be used midseason to control Varroa.