Bob:
> The final word from the USDA_ARS on "disappearing disease" was that it was
not caused by a pathogen but was a genetic problem.

SEE:

Disappearing Disease: III. A comparison of seven different stocks of the
honey bee (Apis mellifera) by  Kulincevic, Jovan M. Rothenbuhler, Walter C.
Rinderer, Thomas E. Keywords: honey bees Apis mellifera bee diseases honey
bee colonies Issue Date: Jun-1984 
  
Variation in North American Stocks of Bees 

There seems to be a strong feeling among some beekeepers that DD is due to
some hereditary deterioration. The same idea has been expressed by some
scientists (24). Our investigations were designed to reveal such a
deterioration of certain stocks of bees if it does indeed exist.  

Australia, over many years, has experienced severe "disappearing trouble".
It appears when they have a winter-nectar flow from two species of
Eucalyptus and no pollen flow. Death rate goes up because of an accumulation
of old bees and poor nutrition, while birth rate goes down because of lack
of pollen and perhaps lack of egg laying space.  

The primary cause of the failure of colonies to build up in the apiaries
from which the 1977 HRDD stock came seems to be disease. EFB, sacbrood, and
chalkbrood were seen. Some colonies showed all three. All 12 nuclei that we
received showed chalkbrood. Furthermore, adult bees were sluggish and showed
symptoms of hairless-black syndrome. Brood was abandoned in some colonies. 

From our data we can offer no support for the genetic hypothesis of DD. 

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