John:  I have long considered Nosema as the UNTREATED disease, because most
beekeepers have no idea that their bees are sick with it.  Much (too much) has
been made about the deposits of bee feces all over the front of a colony is
THE indicator of nosema disease in the colony.  Dysentery (diarrhea) is a
condition of nosema, BUT dysentery can be caused by many other things other
than nosema.  It is too bad that Basil Furgala of Univ. of Minn. is dead,
because he was a foremost authority on nosema.  It has bee estimated that 2/3
of all the bees in the U. S. have some nosema infestation present!  TWO
THIRDS!  WOW!  I can't do much work or win any races when I am suffering
"loose bowels", and I reckon that goes for a honeybee too.  There is a field
test for nosema:  Using forceps, grab the extreme rear segment (site of the
stinger) of the abdomen of a live bee and carefully pull.
You should be able to pull the rectum and ventriculus (mid-gut) from the bee
as a long connected unit.  A HEALTHY ventriculus is straw-colored and ridged
with expandable intestinal muscles.  The ventriculus of a nosema sick bee is
white, and swollen where the expandable muscular rings no longer show.  This
can be done in the field WITHOUT a microscope.  Get a bee inspector to
demonstrate..
Nosema shortens the bee's life (less honey), it pre-ages a bee, so the bee
might be a lousy nurse-bee or lousy comb builder, and it slows the queen's egg
laying ability.  In other words, a good beekeeper does not want nosema in his
apiary.
Nosema is easily controlled by the PROPER use of fumagillin, aka Fumidil-B.
For an established colony, you feed in the FALL 2 gallons of 2:1 sugar syrup
containing 100mg. fumagillin per gallon (read the directions to know the
amount of Fumidil-B).  I used the word PROPER above, because some beekeepers
have trouble following directions.  You put Fumidil-B in 2:1 winter storage
feed, so the bees are getting some medication all winter long into the spring,
even including its use in larval feed of the spring's new bees.  In Maryland,
I feed in November.
It is suggested that all new package bees get a spring feeding of 1 gallon of
1:1 sugar syrup containing 100mg. of fumagillin.
Dr. Shimanuki strongly encourages treating for nosema as just an additional
way of preventing colony loss by parasitic mite syndrome (PMS).  My bees are
healthy because I follow "Doctor's orders".
You asked about "extender" patties life.  In 65 years I have never ever used
Terra-mycin, because I want to KNOW if my bees have AFB before I contaminate
my other apiaries, my friend's bees, my tools, my car, and all of my 1000+
hive bodies.  However, I know that Terramycin and water (dampness) do not go
hand-in-hand, so I would simply closely follow the label directions.  Ask a
scientist who deals with Terramycin for a good answer.               George
Imirie