Aphids and mealy bugs will leave a honeydue deposit on the branch joint.
Ants come along and eat the honeydue and leave the black mold looking
deposits on your bamboo. This does not hurt your bamboo but it is unsightly.

I have found that horticultural oil spray will kill the aphids that leave
the deposits preventing the ants from leaving the deposits. One treatment on
P. n. henon has prevented the return for over 3 years now.

Bert

"Eddie" wrote in message
...
My black bamboo is getting a lot of a black mold-like growth on it. It's
in
clumps (about a quarter to one-half inch in diameter) around the base of
the
leaves and stems. Located in central-eastern NC.
Any ideas on what it is and should I treat it with anything?
Thanks,
Ed