Black Powder

[Kenyadenola]

I have noticed on my Paul Robeson that there seems to be a black powder on the bottom of the stem, working it's way up. The powder has spread to leaf clusters with them turning black and then shriveling up and dying, but not falling off. I will try to post pictures later.

The rest of the plant is fine, the fruit that was closest to the stem where I first discovered the black powder has not been affected. Any ideas?

Thanks