>Considering the fact that varroa quickly becomes resistant to

> amitraz, and considering it has been used for 30 years, I would steer
>> clear of it.
>>
>
The above certainly seems like an oxymoron.  And this is something that
surprises me about amitraz--I thought that it would be completely useless
by now.

>I received absolutely no response, but ask again, does a chemical have to
kill to be useful?

I've spoken with Dr Benoit Siefert, the chemist for Apivar about this.  He
suggests that Apivar does not need to actually kill the mites--all that it
needs to do is to disrupt their behavior enough that they no longer
reproduce successfully.

This is a very important concept in mite management.  One does not need to
kill a single mite in order to control varroa--all one needs to do is to
cause the rate of successful reproduction from the "normal" baseline (in
non-resistant bees) of 94% to drop to about 70% (seven offspring for every
10 foundress mites per generation).  At that point, normal mite attrition
matches the reproductive rate, and the mite population no longer increases.

Subsequent generations of miticides may well act as mating disruptors,
rather than exhibiting toxic effects.  ARS is working on it.  Some of the
essential oils may have this effect.


-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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