>Allen, I feel that your total mite estimate is likely a bit high.  I checked
>with various conversions, e.g.,
>https://secure.fera.defra.gov.uk/beebase/public/BeeDiseases/varroaCalculator.cfm
>and come up with estimates of 2500-3500.

As I say, I am going by my own experience.  Mite drop was the only monitoring 
method I used back when I ran thousands of colonies and never lost one to 
varroa (to my knowledge).

>So phoretic infestation level may well be as little as half  of your rough
>calc, or 8%.  However, your estimate of 30,000 bees may also be high, which
>would then raise the infestation percent (this is one reason that I prefer
>alcohol wash to natural mite drop).

Alcohol wash is the gold standard, short of counting every mite, but as we have 
seen, it has to be done right or can be out by *a factor of five*. (That does 
not make drops look quite as bad, huh?

As for the 30,000, I was going by the number of packages we shook 
depopulating the hives in mid-October years back when I shipped packages
to Arizona.  The hive average was 8lbs.  As I say, I am applying my own 
benchmarks, and I figure that being within +/- 100% is close enough in such 
rough and unknown matters.

> Below 50 mites, a substantial number survived and made grade in almonds.  
> Above that, you might as well save yourself effort and walk away from them.

That is surprisingly good and much better than I would expect.  

>> > I checked the drop against washes in my outfit last year and got a good
>> fit with my method and timing, albeit on a small sample.

>I have done on a larger scale, and came up with a coefficient of correlation
>near zero!  Really surprised me.  That was when I gave up on natural mite
>drop as being meaningful if not taken over a long series.

That does not sound plausible to me.  Something is fishy.  I used three or four 
days and sometimes a week.  Seldom less.  How long did you think to be "long"?
I was also operating in an isolated area where a semi steady-state could be assumed.

>Sorry if I misled.  Eischen's data was separate from the CAP project, which
>was packages.  Eischen's was with commercial migratory hives.  However, I
>agree with you on the virus issue!

That is increasingly looking like the real problem.

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