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Common Crupina

Posted by cahnrs.webteam | November 13, 2013

Also Known As: bearded creeper

Common Crupina is a Class A Noxious Weed: Non-native species that are limited in distribution in Washington. State law requires that these weeds be eradicated.

Common crupina (Crupina vulgaris Cass.), native to the Mediterranean region of Europe, is a federally listed noxious weed that has invaded lands in California, Oregon, Washington, and Idaho. This erect winter Image_002annual reproduces by seed. The seedling’s first 2 leaves (cotyledons) are large, fleshy, shiny, and dark green, with a prominent mid-rib that may be purple to red. Common crupina overwinters as a rosette. As the plant bolts in spring, the stem and leaf margins develop short, stiff spines. Mature plants reach 1–4 feet tall and have multiple branches. On the lower plant stem, alternately arranged leaves are lobed, while on the upper stem they are finely dissected into lacelike leaflets that grow increasingly divided and smaller toward the apex. Common crupina produces flowers from May/June until soil moisture is depleted. Slender, ½-inch long flower heads contain pink to purple flowers that partially protrude through a whorl of stiff bracts. Each plant can have as many as 40 flower heads and each individual head produces 1–5 seeds (achenes). The seeds can remain viable for 3 years under field conditions and have an estimated 85-99% germination rate. Seeds are dark, about the size of a kernel of wheat and have a distinct ring of dark, bristly hairs (pappus) encircling their broad end, resembling a fishing pole.

Two varieties of crupina vulgaris are found in the Pacific Northwest. Washington’s infestation is C. vulgaris var. brachypappa. The infestations found in Idaho, Oregon, and California are C. vulgaris var. typica. The 2 varieties can be distinguished by their seeds. Var. typica achenes are 4–5 mm long and the longest pappus silk is 7–8 mm, while var. brachypappa achenes are 3.5–5.0 mm, with pappus silk of 4–5 mm.

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 Photo by: USDA APHIS PPQ Archive Bugwood.org                        Photos by: Utah State University Archive, Bugwood.org

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Photo by: Utah State University Archive
Utah State University, Bugwood.org
Photo by: Joseph M DiTomaso
University of Cal-Davis, Bugwood.org
Photo by: Steve Dewey
Utah State University
Bugwood.org

 

Common crupina is an aggressive invader from the same botanical tribe (Cynareae) as the knapweeds and yellow starthistle. While common crupina may casually resemble certain knapweed species, the knapweeds have flower receptacles with
bristles and leaf margins without bristly hairs. Adapted to a wide range of soil and growing conditions, common crupina invades disturbed grasslands, pastures, rangeland, open forest lands, roadsides, and waste areas in the western United States. It forms dense stands that reduce forage species, displace native plants, and impair plant communities by
reducing biodiversity.

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Photo by: USDA APHIS PPQ Archive, USDA AOHIS PPQ, Bugwood.org

Control Methods

Effective control of common crupina begins with prevention. Since seed is the plant’s only reproductive mechanism, preventing new plants from establishing and producing seed should be the objective of weed control efforts. Because viable seed may pass through the digestive system of cattle, horses, and deer (not sheep), horses and cattle should not be allowed into infested areas and should always be properly managed to prevent overgrazing. Animals coming from crupina-infested range should be quarantined in holding pens for a number of days.

Cultural Control: Healthy plant communities can deter common crupina from establishing, so it is important to maintain vigorous grasses or other competitive plants. For previously infested areas, a revegetation strategy is important in preventing recolonization of the area by invasive plants.

Mechanical/Physical Control: Hand-pulling and hoeing before the plants have flowered and produced seed are effective ways to control small infestations; these measures must be repeated throughout the growing season to remove newly emerged plants. Cutting may actually stimulate lateral branching, thus increasing flower and seed production, but if cutting/mowing is attempted it should never occur after flowering/seed production.

Chemical Control: Herbicides offer a good control option with the caveat that treatment timing and application rate are important for effective control. Herbicides used for control of common crupina include glyphosate, dicamba, clopyralid, 2, 4-D, picloram, and metsulfuron.

More information can be found in the
PNW Weed Management Handbook
Use pesticides with care. Apply them only to plants, animals, or sites listed on the label. When mixing and applying pesticides, follow all label precautions to protect yourself and others around you. It is a violation of the law to disregard label directions. Store pesticides in their original containers and keep them out of the reach of children, pets, and livestock.

Biological Control: No insect or pathogenic biological control agents are currently available in the United States for control of common crupina. Most grazing animals avoid eating the plant once it is mature due to the short, stiff, spine-like hairs covering its leaves and stems and will graze it only if more suitable forage is unavailable.

Questions: contact Steve Van Vleet or phone (509) 397 – 6290

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