Daniel - I had an occurence of dying larvae and a poor brood pattern like
this once. Very much like what David describes.  I tried many times to do
the rope test, but the remains could not be drawn out of the cells like
that.  Many of the cells contained remains that were thick and brownish,
but not ropy.  I think I ended up uniting the failing colony with another,
very healthy one, supplied them with some fresh sugar syrup & TM, and they
cleaned it all up.  I still don't know what the problem was for sure.
Sacbrood could have been it.
 
I did not see any scales, by the way.  Scales on the bottoms of the cells
are pretty easy to see if you are dealing with American foulbrood, and a
telltale symptom.  You can't remove the scales, once they are hardened,
without wrecking the cell walls.
 
I would not rule out foulbrood, but it would be nice to be sure before you
either destroy or re-use those combs.      --     JG
 
David Eyre wrote:
>A couple of years ago I had something that sounds like this in one of our
>production yards.
>        The sealed brood looks good, older brood has patches that don't emerge.
>the queen still lays a good pattern so the frames look normal.I put it
>down to sac brood.
>        After a great deal of fussing around (as nobody knew what it was) I
>requeened, and that stopped it. Our was a definite failure of the queen!