The whole south side of my house is lined by very large and well
established forsythia bushes. I noticed last year that they have
developed some sort of fungus. It had already spread quite profusely
before I ever even noticed it, but I cut what I thought was all of it
off. Apparently this was not the case because now its even worse. It
seems as though I will just have to cut the bushes down to the ground
to get rid of this stuff because there is no way I can trim each and
every one of the infected branches - there are just too many. Does
anyone know anything about this? I thought I'd read somewhere that it
will go away on its own after a few years, is this true? I also read
that it can spread to wisteria, which I have growing nearby. ? Is it
necessary to cut the bushes down? If so, to what height and when
should I do this? I live in TN in zone 7.

Thanks so much!!