At 09:33 PM 11/16/02 -0700, you wrote:
>Since
>drones take 24 days to emerge, and are the favoured brood for mites, one
>would think that 48 days would be a better choice.

But they are eggs for 3 days and I belive mites don't move in until they
are larva.
So the brood cycle we are really talking about is 0 day old larva to adult,
not 0 day
old eggs to adult.  Hence 42 days.

And, don't think for a moment that bees don't raise brood when you don't
expect them
too.  I was finding new drones outside my hives in February last year (in
Ohio).  And
large numbers of them when I finally could open the hives in March.

I does make me worry that even with a very low mite this fall, there may be
a lot of time
for their population to explode late winter before I can get in to do
anything about it.

-Tim