On Sat, 13 Mar 2004 14:24:52 -0500, "Sandy" wrote:

What is witches broom?! Sandy

It's the manefestation of the dreaded virus "Rose Rosette". It is a
devastaing disease.

http://ianrpubs.unl.edu/plantdisease/g980.htm

Fortunately, I've read that if you catch it early enough on long
canes, you can stop the spread before it hits the crown of the plant.
If you don't, you might as well just dig up the plant.

http://ianrpubs.unl.edu/plantdisease/g980.htm

It's caused by mites which transmit the disease. Fortunately, it
doesn't necessarily mean that your plant is infected with said mites,
as the bite of a single one can transmit the disease. That's why
current wisdom is that the plant doesn't *necessarily* spread the
virus to other plants. That's my hope, at least.