"Jim Carlock" wrote in message
. ..
"Leon Trollski" wrote:
I suppose banana's potassium is helpful, beyond that I am unsure if you
mean the blackspot is caused by the banana.

I don't know. I have noticed though that mold and/or fungus does grow
on banana peels, and was thinking that it "might" be condusive to "black
spot" on roses. It's a long shot, the black spot occurs every year, even
before using banana peels for the roses. So I'm currently messing with
some grits, mixing some grits with the banana peels to see if the black
spot decreases/disappears. The rose roots do like the banana peels and
they grow very well when blended banana peels are placed around the
top soil.

Was looking for other opinions concerning the topic. Was hypothesizing
and hoping others would jump in and say something one way or the other.

I think blackspot is prevalent in moist outdoor conditions. Make sure you
don't water the foliage, don't crowd with other plants, and consider an
antifungal powder now and again on affected areas. Best time to apply is on
early morning dew.