Black knapweed (Centaurea nigra) and Spotted knapweed (Centaurea stoebe subspecies micranthos) are declared noxious in the Illawarra District Weeds Authority control area (including Kiama, Shellharbour and Wollongong council areas).
The weed control class is 1. This means that:
“The plant must be eradicated from the land and the land must be kept free of the plant”.
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Must be reported to the Local Control Authority. Seek their advice.