No I don't know the host plant but I will be back at the Gardens tomorrow and I know where to find it. I could perhaps pick a piece and see if the Garden's staff can identify it. I'll let you know.
It's pretty scrappy up behind the Glasshouses. I don't think many of these have names. Actually, my meeting today is with the ANPS so perhaps one of them would come with me to identify it.
Hi Roger, The opinion of the ANPS people at today's meeting is that the plant is Cassinia quinquefaria. Of course, the beetle may have fallen from a Eucalyptus.