I have had 100% of my hives on screen borrom boards, and have considered the
experience excellent with improved ventilation and the possibility of
decreased Varroa populations early in the season.

Knowing this, Sue Cobey, the developer of New World Carniolans, sent me the
following.  Those of you who can read french are welcome to access the
related web site:

Fairly large scale 2 years testing of the screened bottom board tends to
> show that this equipment can increase significantly the varroa
> population if
> it is used with an open bottom in the Quebec context.  It seems that a
> cooler brood chamber means better conditions for the varroa to
> proliferate,
> thus meeting the recent data collected by Kraus & Velthuis on the
> effect of
> temperature on varroa development.  If used with a closed bottom the
> average
> decrease in fall mite counts is 37% on average but with important
> variations.  It seems also that the genetic origin of the queen and the
> location of the apiary both have more impact on the mite levels than the
> screened bottom.  The screened bottom prooved to be a mervellous tool
> for
> sampling varroa populations under all kinds of circumstances (even
> during a
> honey flow.  The screened bottom also shows promise for the breeding of
> varroa tolerant bees, allowing the colonies to fully express their
> grooming
> ability.  A breeding program has been initiated under such conditions.
>
> Unfortunately the research report is only available in french for the
> moment.  A french summary is also available on our web site (under
> "Recherche & développement").  We will let you know as soon as a
> translation
> becomes available.
>
> Jean-Pierre Chapleau
> Les Reines Chapleau
> 1282, rang 8
> Saint-Adrien, (Québec)
> Canada
> J0A 1C0
> tél: (819) 828-3396, fax: (819) 828-0357
> site web: http://reineschapleau.wd1.net

Lloyd
Lloyd Spear, Owner of Ross Rounds, manufacturer of comb honey equipment
for beekeepers and Sundance pollen traps.
http://www.rossrounds.com
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