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Subject:
From:
Allen Dick <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Sun, 10 Feb 2002 09:56:46 -0700
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At several meetings I have attended recently, the problem of tracheal mites
has been come up.

Apparently, especially with the current varroa problems, tracheal is often
being ignored, but is once again a very big problem that is causing a lot of
winter loss.

Because tracheal is not a simple thing to see -- detection requires lab
work -- tracheal is going undetected and tracheal losses are being blamed on
other factors.  Moreover, the effects of tracheal are additive to those of
varroa, and levels that were previously thought harmless can now cause
colony death.  10% used to be considered the threshold for worry.  Now 5%
can be a cause for alarm.

There is a lot of variability in a yard and if a yard sample comes in at
10%, that can mean that some hives are at zero, and others at 50% or more.
10% in an individual hive puts it at risk, especially if there are other
pressures to consider like varroa, and the effects of varroa treatments on
the bees..

I would advise all readers to get samples to a lab for tracheal tests ASAP
if they have not been treating, and to begin to consider immediate treatment
options.  Although TM losses often occur in winter, they can continue into
spring and one or two simple early treatments can save hives that otherwise
may suddenly die unexpectedly.

For details on treatment options, search the BEE-L archives at
http://www.internode.net/honeybee/BEE-L/ for keys such as menthol and formic
and tracheal.  The blue shop towel is apparently one of the best, as is the
grease and menthol cardboard insert method.

For formic acid, three 30 ml Dri-loc pad 65% treatments, applied a week or
so apart, are required (unless a long term pad is used).  If varroa is also
a target, the treatment needs to go to six pads about seven days apart.

For menthol, two treatments of 20 ml spaced about ten days apart are
necessary for good tracheal control (I know of no effect on varroa from
menthol).  The grease formulations work best because they ensure
evaporation.  Grease should be 20% to 50% of the mix.  Ambient temperatures
should be reaching 20 degrees C (70 degrees F) daily for good evaporation
and assured success.  Under cooler conditions, wrapped hives may be able to
generate enough internal heat for successful treatment.   Warning: menthol
applied in mesh bags doesn't work well, and wastes expensive menthol.  Don't
use that method unless you know it works for you.

In cool weather, either formic or menthol treatment should be on the top
bars.  In hot regions (over 25 degrees C), bottom treatments may be
preferable.  Ask around locally.

After treatment, dead mites will be seen in trachea for the life of the
individual bees, so re-testing will not be able to easily prove success.
After the old bees have died (hopefully of natural causes), testing will
show low levels -- if the treatment was successful.

allen
http://www.internode.net/HoneyBee/Diary/

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