Subject: Re: Open Mesh Floors/Large Entrances
Date: Fri, 19 Jan 2001 08:52:56 -0800
From: "deelusbybeekeeper" <deelusbybeekeeper@excelonline.com>
To: <BiologicalBeekeeping@egroups.com>

Hi to all on Biological Beekeeping:

Dave wrote below:
>
> I am not an "expert" on Open Mesh Floors and their usage but I can give a
> few pointers as I have followed the saga for about 19 years.
> Stress is the usual cause of chalk brood, I do not think OMF makes this
any
> worse.
>
> Cold climate is not a problem, these OMF have been used in Scandinavia and
> Germany (where it is very cold in winter) indeed I believe they were first
> tried out in these very cold locations.

Reply:

Thank you for your reply Dave. Also Erik. I have gained more insite into
OMF. However, I am still a little concerned with weaker colonies and sick
colonies going into winter with OMF or maybe they are not used on these type
colonies because of already having problems, or do you winter them anyway
with OMF?

My concern is because I read under Chalk-brood the following "Experiments
have shown that brood is most susceptible when chilled immediately after it
has been capped (Bailey, 1967b) (fig.14) The chilling need be only a slight
reduction of temperature from the normal 35C to about 30C, for a few hours;
and it can easily occur, even in warm climates, in colonies that temporarily
have insufficient adult bees to incubate their brood adequately......The
smallest colonies are at the greatest risk of becoming chilled because they
have the lowest capacity for heat and relatively large surface areas. Heath
(1982a,b) in extensive reviews, quotes several observations that chalk-brood
is aggravated when colonies are rapidly expanding in spring, i.e. when the
ratio of brood to adult bees is high, or when it is increased
experimentally, and that very small colonies used for mating virgin queens
or in observation hives are very susceptible. Text: Honey Bee Pathology 2nd
edition, Bailey & Ball.

Dave, this makes me think that the open floors and/or accompanying cracks
for drafts, or auger holes in top super, or left open large entrances, can
make for disasterous situations for weak colonies and sick colonies making
them worse.

Can you give me any further insite either, you or Erik, from personal
experiences, so I can rationalize further for understanding?

Sincerely,

Dee A. Lusby
Tucson, Arizona
USA