>I don't think there can be a recommended "optimum re-treatment interval"

>Like any tool, there's a measure of art that accompanies its use. 

Both profoundly true. The saying "For all complex problems there are simple answers, and they are all wrong" is ringing in my ears.

Any controlled study is going to be good only for those colonies at that place at that time. There are mathematical models that say a 90% kill at anytime during the season will have beneficial effect. Models that say 4 treatments anytime  will work. Lots of optimum time line models. My experience this year after more sampling then I have ever done is that the assumption of a 90% kill of phoretic mites from a single OAV treatment can't be relied on. To Bill T. I say that that is true with both wand and fogger type. I have and have tested both. I have experienced numbers that defy any explanation (to me) other than ineffective kill on select colonys with both. 

There are just too many variables. Starting level, brood level, ambient conditions, colony size, influx, point in seasonal colony population dynamics, vapor dispersion, and the big one, efficacy. The consolation for me is that 4 treatments in late summer/early fall seems to work for 80%+/- of my colonies. Once you have more than a few colonies it is impractical to test-treat-retest all colonies. Even if you do conditions can be very different a week later. So do you live with the knowledge that a significant number of colonys are going to crash for real financial loss and possibly infest others ? Hope they make it to a "no brood" treatment ? Treat all as you do your worst case ? I have only questions and no answers.

The extended OA treatment that Randy is working on will probably get a lot of acceptance, I'll try it. In my neighborhood all the big boys already have constant "mystery patties" in all colonys all year. And they don't universally work by the way. Remember the extender terra patties of yore. This approach does not have a good history, maybe this time will be different. 

My wish list for Santa. 1. An INSTANT mite monitor that will tell me right know what the mite level is so one can treat accordingly. Jerry B.? 2. Bees that wont tolerate no stinking mites. And of course peace on earth and goodwill toward men.

Paul Hosticka
Dayton WA

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