issg Database: Management and Information Links for Centaurea diffusa

Centaurea diffusa (herb)

Ecology Distribution Management
Info Impact
Info References
and Links Contacts

         Management Information

As a precaution, anyone working with diffuse knapweed or other knapweed species should wear protective gloves and avoid getting knapweed sap into open cuts or abrasions. Carpenter and Murray (Undated) report that a successful management program should set a goal of < 5% C. diffusa cover. This is the assumed density of the weed in its native range. Lasting control will require a combination of proper land management, biological control, physical control, chemical control, and suppression by desirable vegetation. This "cumulative stress" method will keep the plant constantly under stress, reducing its ability to flourish and spread. An effective management program needs to first control existing infestations, and then develop a land management plan to deter re-infestation. Since it reproduces entirely by seed, the key to controlling existing infestations is to eliminate new seed production and deplete the existing seed bank. Effective, long-term control will be extremely difficult without development of effective biocontrols. Once the existing infestation has been controlled, steps such as hand pulling or spot herbicide treatment programs should be taken to deter any new infestations; this should be done three times annually for several years to eliminate any seedlings that germinate from seeds that break out of dormancy.
For details on chemical, physical, biological control options, please see management information.

         Location Specific Management Information
Arizona (United States (USA))
It is a restricted noxious weed in Arizona (Carpenter and Murray, Undated).
British Columbia (Canada)
It is listed as a noxious weed in British Columbia (Carpenter and Murray, Undated).
Colorado (United States (USA))
It is a designated undesirable species in Colorado (Carpenter and Murray, Undated).
Manitoba (Canada)
It is listed as a noxious weed in Manitoba (Carpenter and Murray, Undated).
New Mexico (United States (USA))
t is a candidate species for the New Mexico noxious weed list (Carpenter and Murray, Undated).
Ontario (Canada)
It is listed as a noxious weed in Ontario (Carpenter and Murray, Undated).
Utah (United States (USA))
It is a designated weed species in Utah (Carpenter and Murray, Undated).

         Management Resources/Links

1. Alien Species in Poland Centaurea diffusa
        Summary: In 1999, the database on species introduced into Poland was developed at the Institute of Nature Conservation, Polish Academy of Sciences in Krakow for the Ministry of the Environment. In 2003, thanks to a grant from the US State Department, part of the data was translated and made accessible on the Internet. In 2003-2005, as a result of cooperation between a group of experts, new species were included. In 2005, the Polish database became a part of NOBANIS http://www.artportalen.se/nobanis/ which is an important gateway to data on invasive alien species in Northern and Central Europe.
Alien Species in Poland is available from: http://www.iop.krakow.pl/ias/default.asp
This page is available from: http://www.iop.krakow.pl/ias/species.asp?66 [Accessed December 15 2006]
2. Carpenter A. T. and Murray T. A. [Undated]. Element Stewardship Abstract for Centaurea diffusa Lamarck. The Nature Conservancy.
        Summary: An Element Stewardship Abstract containing detail report on description, distribution, dispersal methods, impacts, habitats and control.
3. European and Mediterranean Plant Protection Organization (EPPO), 2006. Guidelines for the management of invasive alien plants or potentially invasive alien plants which are intended for import or have been intentionally imported. EPPO Bulletin 36 (3), 417-418.
4. National Agricultural Pest Information System (NAPIS), April 1993 Fact Sheet Center for Environmental and Regulatory Information Systems, Purdue University.
        Summary: Detailed report on description, distribution, impacts, habitats and control.
5. NWCB (Noxious Weed Control Board) 2001 Written Findings of the State Noxious Weed Control Board - Class B - B-designate Weed: Diffuse knapweed (Centaurea diffusa Lam) Washington State Department of Agriculture, Washington
        Summary: Short summary of description, distribution, habitat and management.
6. Rejmanek and Pitcairn, 2002. When is eradication of exotic pest plants a realistic goal? In Turning the tide: the eradication of invasive species: 249-253. Veitch, C.R. and Clout, M.N.(eds). IUCN SSC Invasive Species Specialist Group. IUCN. Gland. Switzerland and Cambridge. UK.
        Summary: Eradication case study in Turning the tide: the eradication of invasive species.
7. Roche, B. and C. Roche. 1999. Diffuse Knapweed. In Biology and management of Noxious rangeland weeds. Edited by R. Sheley and J. Petroff. Oregon State University Press.
        Summary: Management and Control.
8. Whaley D. K. and Gary P. L., June 2002 Defusing Diffuse Knapweed: Biological Control of an Explosive Weed Agrichemical and Environmental News, June 2002, Issue No. 194
        Summary: Detailed report on description, dispersal methods, habitats and control.
         Results Page: 1

The Global Invasive Species Database is managed by the Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission. It was developed as part of the global initiative on invasive species led by the Global Invasive Species Programme (GISP) and is supported through partnerships with the National Biological Information Infrastructure, Manaaki Whenua-Landcare Research and the University of Auckland. Conditions of use.