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bob darrell wrote:
>
> Resistance to various chemicals is documented, but I have never seen
> any reports of resistance to Formic acid or Oxalic.
>
Takes time. There were no reports of tolerance to any of the other
pesticides until the mites developed it.
The shorter the generation, the faster the tolerance, which is why
scientists love to study fruit flies.
It seems that ten or so years is the norm for Varroa reacting to
something completely new, like Apistan. And, as Randy said, a mix of
treatments will go a long way to keeping tolerance from occurring.
I use the term tolerance instead of resistance because that is more of
what happens. You might have resistance in some of the mites but not
all, so you still get kills even with Apistan and a "resistant" colony.
In fact, Apistan is still used to get a quick mite drop count in field
trials.
Bill Truesdell
Bath, Maine
-- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---
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