Since we are on the topic of fruity smelling things and chalkbrood may I add
thymol on the list of potential cures.  Vita Europe produces a thymol gel
product called Apiguard.  Their web page claims (get to it through
www.beekeeper.com):

' (Apiguard) has a proven high efficacy against the varroa mite and is also
active against both tracheal mites and chalkbrood.'

There are in fact 2 papers which support the claim that thymol may inhibit
chalkbrood growth.  The first one was conducted by the USDA (Calderone,
Shimanuki and Allen-Wardell) and showed if you dissolved as little as 100ppm
thymol in artificial media, a mummy of chalkbrood would not grow for 72h (it
will about 2.5 cm radially when no thymol is present).

The second study, unfortunate for me, is in French.  Reading from the
translated abstract, thymol slowed the growth of chalkbrood in the lab.  The
use of oil of savory, which contains 4% thymol but 32% carvacrol (another
very smelly plant molecule), incorporated into candy and fed to colonies
sustantially reduced the number of mummies found on the bottom board compared
to untreated colonies.

Does thymol cure chalkbrood?  From the litterature their seems to be some
basis for this, however I have not seen a study where thymol is applied to a
colony and chalkbrood is reduced compared to untreated colonies.  That does
not mean that the study does not exist.  Maybe if there isn't one, this might
be a study worth looking into.

Should you use thymol to combat chalkbrood?

I would say no.  First of all thymol is not a registered antibiotic.  Second,
the margin of toxicity at which thymol kills chalkbrood may not be so much
different from the dose that kills bees.  Most likely it is unknown.  Studies
performed by Chris Lindberg at Simon Fraser University suggest that thymol
kills varroa mites at only 10 times the dose needed to kill bees.  If the
same holds true for chalkbrood it means unless thymol is carefully
formulated, there is a risk that you will do damage to your colony.  Before I
would use thymol I would want to see a study where I saw that their was very
little reduction in adult bee population, brood area or queen survival
following treatment- it just stands to reason.

SURVEY

WHO WOULD REALLY TREAT FOR CHALKBROOD ANYWAYS?
I run into beekeepers who swear they are loosing reams of spring brood to
chalkbrood and others who just shrug and say the odd colony is bad and all
that is needed is to requeen.  For the record, what does BEE-L think:

1. What percentage of your colonies has levels of chalkbrood that you feel
are costing you money (choose the closest)?
 - 0%
 - 25%
 - 50%
 - 75%
 - 100%

2. What kind of reduction in disease severity would be worth the effort of
going on to the bee yard to take some action (choose the closest)?
 - 25% reduction
 - 50%
 - 75%
 - 100%

3. If there was a product, queen source or management technique that would
leave you free of chalkbrood what would you pay per colony per season (choose
the closest)?
 - $0.50
 - $1.00
 - $2.00

4. How bad does chalkbrood have to be before you will requeen (choose the
closest)?
 - I don't requeen, it is too much money and effort for the return
 - a single mummy on a frame or a bottom board
 - I do not have to look far to see signs of mummies
 - a big pile of mummies in the frames and one the bottom board

5. If chalkbrood were a Hollywood villian who would it be (choose the
closest)?
 - Pee Wee Herman
 - one of the bad guys out of a Die Hard movie
 - Scarface

Okay.  Let the answers roll in and i'll summerize the results for the list.

Regards
Adony