?> After a few years without treatment something changes where the mites
seem less virulent.
Just very anecdotal and not all scientific:
I had an interesting thing happen this year. In the last few years, I have
been splitting as much as a I can with the goal of producing bees and
avoiding producing honey. Each fall, I treated with a single drizzle of
oxalic acid and had sufficient control that my mite levels were in the 5%
level or less each fall at the end of brood rearing.
At the end of last year I noticed that AFB was creeping up on me and this
spring I treated all hives with tylosin as recommended, then, later treated
with OTC since OTC hits things that tylosin misses. The bees looked good
after that, and AFB was totally gone. Patterns which had been getting
spotty improved. (I had been adding hygienic and supposedly varroa tolerant
stock).
This fall, I noticed what looked like EFB. while filling feeders at the end
of a day. "That is strange", I thought, since EFB is usually a spring
condition around here, and I can't recall having seen it in my bees ever. I
did not bother to take a very close look, since I was feeding and had a yard
to finish and figured if it was EFB an OTC dusting would fix it. EFB
responds to OTC well.
Then about two weeks? later, I noticed that a powerful hive collapsed since
last visit. It was the one where I had seen the 'EFB', and I realised that
maybe I was seeing something else. I got out the shaker and got high
numbers -- 15-1/2%, 12%, and 22% in nearby hives. I quit testing at that
point and started dialling for Apivar.
Anyhow, every season is different: last year I made honey in spite of
myself. This year I did not. This year I split a bit more drastically and
the weather in August turned out to be bad. There are other things, too,
BUT I'm wondering if this one thing, treating with antibiotics somehow
tipped the balance in favour of the varroa. Maybe varroa mites have
bacterial enemies. Maybe tylosin is a growth promoter for varroa, just as
it is for hogs. Maybe the antibiotics resulted in less hygienic action by
the bees. Maybe tylosin had nothing to do with anything except the better
patterns and absence of AFB.
Anyhow, I wonder if there is a relationship. If so it should not be hard to
prove., unless it only shows up where AFB is also present.
I know, Peter. Don't bother saying it :)
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