In a message dated 22/10/01 05:08:41 GMT Daylight Time,
[log in to unmask] writes:

<< Does anyone know what the estimated ratio is between fallen mites and
living
 ones? If i have a natural mite fall of 20 in 24 hours, how many mites do i
 have in the colony? I suppose the ratio would vary between different times
 of the year, but any input on this would be interesting.

 What is the threshold number of mites where the colony starts to suffer and
 develop secondary problems, such as Deformed Wing Virus etc?

 /Mats (Stockholm, Sweden) >>

Under UK conditions multiply the 24 hour drop by 100 at this time of year.  X
30 in the summer.  DWV cuts in at about 3,000 mites.  All figures rounded and
subject to local variations.

Chris