Dagger-flower | Mantisalca salmantica (L.) Briq. & Cavill.

California Pest Rating for
Dagger-flower | Mantisalca salmantica (L.) Briq. & Cavill.
Synonym: Centaurea salmantica L.
Asterales: Asteraceae
Pest Rating: A |  Proposed Seed Rating: P

Initiating Event:

This plant has been rated as “Q” by CDFA since it was detected in a dried plant arrangement in 2015.

History & Status:

Dagger-flower is a perennial or biennial knapweed native to the Mediterranean Region including Israel, Morocco, and Mallorca. It has spread to Switzerland, Britain, Germany, and southern Scandinavia as a result of anthropogenic disturbance. It occupies disturbed areas, roadsides and rocky areas.

It is occasionally found as a grain or bird seed casual introduction. It is adventive on several continents, although it has not yet become a significant weed of agriculture except in Europe adjacent to its original range.

Official Control: None.

California Distribution:  A single collection from Healdsburg (Sonoma County) is known from 1896. Evidently it did not persist.

California Interceptions: It was submitted to the CDFA botany laboratory in a dried plant arrangements (PDRs #19TP06465296, 130P06398197, 490P06380234, & 500P06138704).

United States: In addition to California, Dagger-flower has been collected once or twice in Arizona as a waif.

International: Dagger-flower is native to the Mediterranean. It is reported as naturalized and as an environmental weed in South Africa. It is also sparingly introduced into Australia and Asia.

This risk Dagger-flower would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 3

Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

Risk is High (3), as the plant is native to an area with a very similar climate. It is very widespread in this area and has spread north in response to human disturbance.

2) Known Pest Host Range: Evaluate the host range of the pest. Score: 3

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

Risk is high (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable.

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score: 2

Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

Risk is Medium (2). The plant produces via numerous seeds that seem to be able to spread rather slowly. The seed bank is moderately persistent.

4) Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 2

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Low (1) causes 0 or 1 of these impacts.

Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

Risk is Medium (2) as the plant could lower range productivity, invade row crops, and could negatively change normal cultural practices.

5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below.

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score: 3

Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Risk is high (3) as the plant could dominate roadsides and invade rangelands as happened with the closely related yellow star-thistle, excluding native plants and lowering biodiversity. If it were to spread in CA, the plant could disrupt natural communities and exclude cultural plants from a landscape.

Consequences of Introduction to California for Dagger-flower:

Add up the total score and include it here. (13)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. Score: -0. Detected once in CA but disappeared.

Not established (0) Pest never detected in California, or known only from incursions.

Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (13)


High. This plant has had the opportunity to invade North America, but it has not succeeded so far. However, the behavior of some of its close relatives, as well as its ability to spread following human disturbance point to a high chance of spread once the species established in CA. Despite 2 known historic detections in the SW U.S., this has not happened.

Conclusion and Rating Justification:

A potentially bad weed. Deserves an A rating as several of its relatives are weeds in California and it comes from a very similar climate. As it is not yet established in California, a conservative approach to exclusion is justified.


Alanen, A., T. Bongard, E. Einarsson, H. Hansen, L. Hedlund, K.Jansson, M. Josefsson, M. Philipp, O. T. Sandlund, A. E. Svart, H. E. Svart, & I. Weidema. 2004. Introduced Species in the Nordic Countries (Denmark) under Nordic Council of Ministers (NMR), subgroup Natur-og Friluftslivsgruppen.

Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley.

Bromilow, C. 1995. Problem Plants of South Africa. Briza Publications, Arcardia, South Africa.

Consortium of California Herbaria (ucjeps.berkeley.edu/consortium/).

Flora of North America Editorial Committee, eds.  1993+.  Flora of North America North of Mexico.  16+ vols.  New York and Oxford.

Hanf, M. 1983. The Arable Weeds of Europe, with their seedlings and seeds. BASF Aktiengesellschaft, D-6700 Ludwigshafen. Germany.

Holm, L. G., Pancho, J. V., Herberger, J. P. and Plucknett, D. L. 1979. A Geographical Atlas of World Weeds. John Wiley and Sons New York, USA.

Susana, A., N. Garcia-Jacas, O. Hidalgo, R. Vilatersana, & T. Garnatje. 2006. The Cardueae (Compositae) Revisited: Insights from ITS, trnL-trnF, & matK Nuclear and Chloropolast DNA Analysis. Annals of the Missouri Botanic Garden. 93: 150-171.

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-0312; plant.health[@]cdfa.ca.gov.

Pest Rating: A |  Proposed Seed Rating: P

Posted by ls