G'day,

The carpark where I work has a number of Bottlebrush trees, most of which
have a black sooty sort of a deposit on the trunk and branches ... almost
like someone has lit a fire under the tree.

I haven't seen any little critters, but from searching on the interwebnet
thingy, it seems the might have a bit of a scale infestation(?)

Any other suggestions as to what it might be, and what the right treatment
would be?