> One of my favourite sites for this topic is
http://www.apinovar.com, although he uses drops instead of washes.

This is an excellent site.
One thing that I'd like to point out with regard to Allen's and my
discussion of natural drop vs alcohol wash is that I am not disputing that
either can be used.

But they must be interpreted differently.  Natural drop thresholds change
greatly over the course of a season--in the above website going from 0.5 to
25, with actual drops often exceeding 100-200.  Natural drop varies greatly
from day to day, so one should use an average (median probably better than
the mean) of several measurements.  The number of mites must also be
adjusted by the strength of the colony, and whether or not brood is present.

Alcohol wash thresholds have a narrower range--1 to 6 mites per 300 bees,
with actual numbers in untreated colonies (in my operation) seldom going
above 50.  At least two washes should be done to confirm accuracy.  No
other allowances need to be made.
-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm