> One side of one frame has a patch of foul brood I think ...
> I installed new patties today. Will this keep it in check or do I have a
> real problem on my hands?
 
They say that patties will not clean up AFB, they will only prevent it --
if used correctly.
 
We used grease patties again this year for the first time in about 15
years.  This time we used them for their reputed mite suppression
properties as well as for AFB and EFB.
 
Usually we just dust and use TM in syrup, but this year we have used no
dust and only added TM to syrup and the patties.  (FWIW, we also fed
non-medicated *pollen supplement* patties as long as we could get into the
brood chambers easily; we even have them on nucs right now  Our theory is
that well nourished bees are more resistant to any disease or pest).
 
AFAIK, in about 2000 colonies we haven't seen any AFB or EFB although we
were going through the colonies regularly splitting all spring.
 
The only exception I can recall is one colony I saw somewhere with a
little bit early in the spring.  I didn't do anything special with it since
it was in a distant yard, I had no dust along,  and since it was morning
and I had a full day ahead, I did not want to take it home.
 
So, it appears that the patties may be working well for us in combination
with  the medicated feed.  Usually we see a few more hives with a touch of
AFB than that.
 
Anyhow, dusting with a  1:5 TM / icing sugar mix is usually required to
*clean up* (as opposed to preventing) any active AFB, and removing any
combs with hard scale (or flattening the cells so the bees tear them down
and rebuild) is always wise, since unless the colony is large and
conditions are just right, the bees may not be able to deal with it.
Besides the scale is usually right in the middle of your brood chamber
occupying prime real estate.
 
A heaping tablespoon of the dust should be applied to the top bars of
frames in each brood chamber and the dusting repeated weekly until all
traces of AFB are gone.  BTW,  If the bees do not remove the dust between
dustings, it will obviously not work.  I have seen beekeepers also dust the
infected (and flattened) comb area a bit.  Avoid getting the dust on any
larvae you want to remain alive, since even a grain or two of the mixture
will kill.
 
No medication should be used during any honey flow that will be extracted
or while collecting pollen for human consumption.
 
And the usual caveat: YMMV
 
>  I've read the old school would burn the hive.
 
Yup, they will definitely recommend such measures.
 
In some areas and countries where AFB is virtually non-existent it is
probably (definitely?) wise, but for most of us it is like spitting into
the wind...
 
Used correctly, TM will save your hive and your bees *and* within a year or
two the chances of having a repeat breakdown in that hive will be no
greater than that of any other hive within 5 miles.
 
Hope this helps.
 
Allen