> I would offer that the hard evidence of comb testing for residues
outweighs

> any anecdotal reports of "thriving".  That would be a more scientific
> approach to beekeeping.
>

To me, a "scientific approach" also involves trusting what you observe in
the field with your own eyes.

I am not arguing with the above member in any way, nor discounting that
comb contamination is a potential issue.

Indeed, I was quick to hop on the "contaminated comb" bandwagon, since it
is clearly supported by both residue analysis, and with studies (such as
Judy Wu's) that demonstrate poorer larval survival, and mores
susceptibility to pathogens, as well as poorer queen larval survival.
There is no question that pesticide/miticide/environmental pollutant
contamination of combs can negatively affect colony health.

But when I did reality checks on both the historical levels of comb
contaminants, as well as seeing that some of the most successful beekeepers
that I know produce huge abundances of excess bees for sale each year on
such contaminated combs, I realized that I needed to weigh the evidence
more carefully.

As another member has pointed out, drawn comb has considerable value.  Not
only can queens lay in it without much preparation, but bees more readily
store honey in it.  Assuming that we can work a drawn extracted honey frame
down in order to replace the rotated out brood comb, we should look at cost
of replacement of that honey comb.

As it happens, I recently ran an experiment to quantify that cost, in lbs
of sugar syrup.  Surprisingly, I found that there was little difference in
whether the sugar syrup was fed as 71% solids, or if diluted to half that
rate.

The cost in sugar syrup per fully drawn comb, after subtracting the amount
of sugar stored in those combs, works out to about 1.7 lbs.  At 40 cents a
lb, that would be a cost of 68 cents to draw that comb.

Of course the "cost" of drawing that comb on natural nectar would be much
higher.  With honey selling at $2 per lb (5x the cost of sugar syrup), the
lost honey crop for drawing that comb would be $3.40.

Add a dollar for the sheet of foundation, and you get a cost of about $1.68
to draw that comb.  You should also add perhaps another dollar or two for
the labor in swapping the foundation, disposal, etc.  So, a reasonable out
of pocket cost for the replacement of a drawn comb would be in the ballpark
of maybe $3.25 (or close to $5 if drawn on natural nectar).

So if a beekeeper wished to rotate out his brood combs on a 5-year
rotation, that would be 4 combs in a double deep brood chamber per year.
Four combs times $3.25 = $13 ($20 if drawn on natural nectar).

So the actual cost of culling a few frames a year is not negligible.  The
annual cost per hive for a 5-yr rotation of combs in the broodnest would be
in the $13-20 range.  For a small operation like mine of 1000 hives, that
adds up.

I've personally addressed the problem by not using synthetic miticides and
avoiding agricultural pesticides as much as possible, but mostly by selling
off a third to half of all my brood combs as nucs every season.  This gives
me fresh combs each year, and nice, relatively new combs to sell in my
nucs.  A win-win situation.  I recover the cost of comb replacement in
setting the cost of my nucs.


--
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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