Help Oxalic Acid.

[Pete L]

Playing devils advocate....could you be selecting for Varroa that cling on / avoid bees cleaning behaviour, rather than "hygenic bees" ?

Lots of low counts pre-treatment this year across the country.

Open mesh floors may be helping towards the natural selection of stronger mites, weaker mites, ones that could of otherwise of just crawled off the floor onto another bee, been less aggressive, as they only slowly amble around, and even lost the use of, or grow less legs, now fall out through the mesh floor, thus removing them and their weakness from the gene pool, leaving only stronger more aggressive mites, ones that may of grown extra legs to hang on even better...so best look out for nine armed/legged mites with extra large biceps.

[Adam]

Playing devils advocate....could you be selecting for Varroa that cling on / avoid bees cleaning behaviour, rather than "hygenic bees" ?

Lots of low counts pre-treatment this year across the country.

Possibly. I was (pleasantly) surprised by the low drop this winter. Maybe I am over-worried by varroa.

I have to admit that I haven't looked for 9 legged varroa yet. However Norfolk is where it will start as everyone outside the county seems to think that we are in-bred and have six toes so having odd mutations is natural to us!

[fatshark]

Varroa are always inbred … it's inevitable if you mate with your son.

[Calum]

Latest advice in Germany is trickle method works best between 0*C and -3*C as the bees are better bunched making the treatment more effective that the (till now recommended) +3*c temperature. This was on the basis of a comparative study of over 300 colonies, so will be verified before the medical treatment documentation (the oxalic treatment is classes as a vet medicine here) will be changed...

[mbc]

Varroa are always inbred … it's inevitable if you mate with your son.

Not necessarily if there are more than one foundress mites in a cell, and isnt it the siblings who normally mate ?

[gavin]

... and have six toes so having odd mutations is natural to us!

Friends' daughter (Scot-SW England hybrid, no Norfolk involvement at all!) had 6 toes. The requirements of modern shoe manufacture dictated that one was removed at a young age.

Yes, the Varroa virgins have a shortish time window to mate with their brother (or a less or unrelated male if the cell had more than one foundress). AFAIK (FWIW!) mums have missed the chance once their sons are at large in a cell.

[nemphlar]

[QUOTE=Adam;23469]Possibly. I was (pleasantly) surprised by the low drop this winter. Maybe I am over-worried by varroa.

I had thought last years low counts were due to the Long brood less period a lot of beeks had seen. I had read somewhere last year that phoretic mites failed after 3 months and dropped off. Can't find it, beginning to wonder if I imagined it.
Wondered if at a convenient time of the year the queens might be induced to stop laying for a similar period

[The Drone Ranger]

Two treatments are more likely to reduce the numbers than one
I have had to settle for one trickle treatment on the 4 Paynes Nucs I am taking through Winter
Its pot luck to some extent whether you get a really high kill rate, so you have twice the chance of nailing them by treating twice
If you are trickling in Winter then your Autumn treatment is more crucial (there is a very good chance of a broodless period then as well)

[snimmo243]

I checked on my two colonies yesterday having used the trickle method last Saturday - the colony that showed 0 natural mite drop over 14 days prior to treatment dropped 300 in 6 days whilst the other colony showing 61 in 14 days = 4.4 per day or 1700 total dropped.... Wait for it 1400 in 6 days post treatment!!!

[nemphlar]

[QUOTE=The Drone Ranger;23489]Two treatments are more likely to reduce the numbers than one
I've tried 2 treatments this year, 2weeks between them, 3 weeks after the first of them I had totals of 350 to 500 mites the last 7 days, the 4th week, I have counts between 0 and 8.
DR do you always treat twice, might be a regular option all this assuming they come through the winter
Ps should mention this is across 6 hives