 Knapweed readily establishes itself and quickly expands in all growth forms in places of human disturbance such as industrial sites, along roadsides, and along sandy riverbanks, and also has the potential to spread into undisturbed natural areas.Thirteen biological pest control agents have been used against this plant and its cogener, diffuse knapweed, including the moths "Agapeta zoegana" and "Metzneria paucipunctella", the weevils "Bangasternus fausti", "Larinus obtusus", and "Larinus minutus" and "Cyphocleonus achates", and the fruit flies "Chaetorellia acrolophi", "Urophora affinis" and "Urophora quadrifasciata".But in general, biocontrol has not been shown to be effective against "C. maculosa".