Hi JimIan, it's the "wide range of products" and times that's my problem. Our longest-standing local beek "never uses OA" [I think he meant sublimation] and we have an even longer-standing, though wobbling a bit these days, member of local BKA who seems not to treat for varroa at all these days. Although I don't trust "varroa trays", and therefore cannot be sure, I suspect we don''t have much, if any, varroa up here in the eastern highlands. None on the west, for sure.
So -- should I treat? When I kept sheep etc, a local ag chappie made sure I treated them correctly and at certain times of year. Never ever seen a bee inspector......
I’d suggest if other members are treating then you’d need to. As for not treating some don’t but management or even lack of can keep numbers low to a point.
Late flows like heather and treatment after will reduce options and negates Thymol type treatment. Unless colonies are treated/prepared before after any main crop is removed.
Chemical strips are Apistan or Apivar…. There’s a couple of other names out there but it’s the same stuff. I’d avoid the Apistan as resistance was showing early 2000s, Apivar will likely go the same way if it’s not already done so. Still appears effective for most!
Oxalic comes in strips can be vaped or trickled, you probably just want to consider strips or vaping. Strips can be used anytime in the active season as vaping. Trickled is only effective during brood less times. So possibly splits or swarms.
As you say you have a vape then 3 times over 5 day intervals and perhaps even a 4th if you are still getting a high drop.