> A "sticky" board under a screen bottom board...
> Stronger colonies naturally yield more mites than smaller colonies.

> Can anyone tell me what percentage of the total mite population
> can be detected in a 24-hour natural mite drop?

While someone might claim to be able to estimate this, it really
does not matter in my view.  All that matters to me is the trend line
("the slope of the curve") from the last few 24-hour drop counts to
the current.  If it is "linear", one need not treat, but if it is
going exponential, then one may need to remove the colony from
production and treat.

> Is there a formula to suggest how many total mites each fallen
> mite represents? How many mites does it take to be considered
> the "economic threshold"

You answered both questions in your second line above.

> or is this purely relative to the size of the colony?

Exactly.  Your biggest colonies will have the largest absolute
numbers of mites, so arbitrary thresholds are counter-productive
given that no two colonies will be the same size.

> By the way, I have some strong, productive colonies dropping 136
> mites in a 24 hour period, and a number of colonies dropping
> anywhere from zero to three (and all in the same bee yard).

While 3 * 45 = 136, and it would be hard to imagine a colony with
45 times the bee population of another colony, drawing conclusions
from a single reading in isolation, rather than a series of readings
over time, is a dangerous game, as you don't know when each monitored
colony last had no detectable mite drop.

For example, a more populous colony would have a higher incidence of
bees bumping into bees, crawling over each other, and doing other
things that might be inflating the natural mite drop through knocking
more mites off both bees and comb.

                jim   (It is now legal to buy drugs abroad,
                   but still illegal to buy a broad drugs.)

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