Common crupina or Bearded creeper [Crupina vulgaris Cass.][CJNVU][CDFA List: A][Federal Noxious Weed] Photographs Map of Distribution




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[
SYNONYMS] [GENERAL DESCRIPTION] [SEEDLINGS] [MATURE PLANT] [ROOTS and UNDERGROUND STRUCTURES] [FLOWERS] [FRUITS and SEEDS] [POSTSENESCENCE CHARACTERISTICS] [HABITAT] [DISTRIBUTION] [PROPAGATION/PHENOLOGY] [MANAGEMENT FAVORING/DISCOURAGING SURVIVAL] [SIMILAR SPECIES] [CONTROL METHODS]

SYNONYMS:bearded creeper, Centaurea crupina L., Serratula crupina (L.) Vill.

GENERAL DESCRIPTION:Winter annual, with erect, openly branched flowering stems to 0.6(1) m tall at maturity. Most germination occurs after the first significant rains of fall/early winter, but germination can continue throughout the rainy season. Fall germinating plants exist as basal rosettes until flowering stems bolt in spring. Rosette leaves whither as flowering commences in late spring/early summer. Plants adapt to many environmental conditions, are highly competitive for water and nutrients, and often produces solid stands. Introduced from southern Europe.

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SEEDLINGS:Cotyledons oblong, 1-2.5 cm long, and fleshy. Midvein and margins often purplish-red. First rosette leaves entire with toothed margins. Subsequent leaves increasingly lobed.

MATURE PLANT:Rosette leaves oblong to obovate, to 8 cm long, sessile or petioled, covered with short stiff hairs, and deeply once-pinnately divided with lobes narrow and opposing. Stem leaves alternate, reduced near stem tops, and pinnately (sometimes bipinnately) divided with narrow lobing. Rosette and stem leaf margins appear spiny-toothed with stiff hairs barbed at the tips (glochidiate). Stems longitudinally ridged.

ROOTS and UNDERGROUND STRUCTURES:Dense, fibrous roots.

FLOWERS:June until soil moisture is depleted. Flower heads on stalks 1-3 cm long, consist of 1-2 central fertile disc flowers and 2-4 outer sterile disc flowers. Corollas are slender purple tubes with linear lobes, together ~ 14 mm long. Phyllaries lanceolate, in several overlapping series, and as a unit, 8-20 mm long and slender urn-shaped. Receptacle with flattened, scale-like chaffy bracts.

FRUITS and SEEDS:Fertile achene nearly cylindric, 3-6 mm long, 1.5-3.5 mm wide, base rounded, appex +/- fat-topped, black-brown, +/- covered with minute, lustrous golden-brown scales that rub off easily. Pappus bristles black-brown, glossy, stiff, radiate outwards at a 90º angle from the achene axis in 2 unequal series. Outer bristles inconspicuous, scale-like, flattened, to ~ 1 mm long. Inner bristles stiff, minutely barbed, to ~ 10 mm long. Above the bristles is a +/- erect crown of flattened scales ~ 1 mm long.

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POSTSENESCENCE CHARACTERISTICS:Flower heads remaining on old stems can aid with species identification. Refer to the Flower Head Comparison of White, Pink, or Purple-flowered Centaurea and Related Species Table for comparison.

HABITAT:Grassy sites, rangelands, forested areas, and roadsides. Adaptable to many moisture and temperature regimes and soil tupes.

DISTRIBUTION:Uncommon. Modoc Plateau (sc Modoc Co.); southern North Coast Ranges (ce Sonoma Co.); to 250 m (850 ft). Also Idaho, Oregon, and Washington; to 1000 m (3200 ft).

PROPAGATION/PHENOLOGY:Reproduces by seed. Flower heads often disperse as a unit. Seeds (achenes) fall near the parent plant or disperse to greater distances with rodents, livestock, game birds, human activity, and by floating on water. Seeds typically do not disperse beyond 1.5 m from the parent plant with wind or 90 m (300 ft) on the hooves of livestock. Seed can survive ingestion by most animals, except sheep. Plants produce 1(2) achenes per flower head and about 130 achenes per averaged size plant. About 85% of seeds produced germinate the following fall. Seeds germinate under a wide range of temperatures and can remain viable for up to 3 years under field conditions. Plants are grazed only when more suitable forage is lacking.

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MANAGEMENT FAVORING/DISCOURAGING SURVIVAL:Quarantining cattle and horses for at least 6 days after foraging on rangeland infested with flowering plants can help prevent the introduction of common crupina to non-infested sites.

SIMILAR SPECIES:Several knapweeds in the genus Centaurea and Russian knapweed [Acroptilon repens (L.) DC.] superficially resemble common crupina. Unlike common crupina, the knapweeds have flower receptacles with bristles and leaf margins without bristly, barb-tipped hairs. Phyllary and achene characteristics are important in distinguishing these species. Refer to the Flower Head Comparison of White, Pink, or Purple-flowered Centaurea and Related Species Table for comparison.

CONTROL METHODS:

Prevention: Common crupina is an aggressive invader from the same botanical tribe (Cynareae) as the knapweeds and yellow starthistle. It is an unpalatable forage for cattle and forms dense, monocultures in disturbed rangeland, canyon grassland, and waste areas. Crupina is adapted to a wide range of environmental conditions and will likely increase unless preventative measures are utilized. Since seed are the only reproductive mechanism and are relatively short lived (less than three years), the probability of eradication is higher than some other noxious weeds. Therefore, the prevention of new plant establishment and seed production is critical. Crupina flowers and produces seed throughout the summer as long as adequate soil moisture is available. Natural seed dispersal occurs by wind and rodents for shorter distances, and by water and in the hair of deer or cattle for longer distances. Viable seed may also pass through the digestive system of cattle, horses, deer and chinese pheasants, but not sheep. Therefore, horses and cattle should be removed from infested areas to avoid overgrazing of desirable species and possible seed dissemination. Crupina may be found in some pastures and hay producing areas. Therefore, use certified weed free hay for winter feed and quarantine cattle in holding pens if animals have come from crupina infested range.

Mechanical: Mechanical control may be limited on steep slopes or rugged range areas. However, hand pulling, hoeing, or tillage before flowering will be effective for controlling small infestations. Infestations should be checked every two to four weeks in the spring for newly emerged plants. There is little information available on using mowing as a control strategy. However, it is not recommended after plants have begun producing seed due to the likelihood of increased dissemination.

Biological
: There are currently no available insect or pathogenic biocontrol agents for use on common crupina. Most grazing animals will avoid it, unless no other plants are available. This will result in natural selection for crupina. Therefore, maintaining healthy, competitive grasses, and minimizing overuse is the best deterrent to invasion by crupina.

Chemical: Since other control strategies are limited, herbicides may be the most effective means for eradicating larger infestations of common crupina. However, there are few herbicides currently labeled for use in California. Tank mixes of dicamba (0.5 lb ae/A) + 2,4-D (1.0 lb ae/A) applied in the fall or spring will provide season long control. Retreatment may be necessary for two to tree years to ensure seedbank depletion. These herbicides will injure or kill any other susceptible broadleaves they contact. Later spring applications may reduce control variability, but may increase the risk of injury to perennial forbes or shrubs due to volatilization. Spring applications of gyphosate (1.0 lb ae/A) will also provide season long control but will kill or injure any other vegetation present. Sequential fall and spring applications of clopyralid (0.13 lb ae/A) or triclopyr (.25 lb ae/A) also provide >95 % control. Clopyralid (Transline)will injure legumes and triclopyr will injure or kill other broadleaves. Picloram (0.5 lb ae/A), which is not labeled in California, will effectively control common crupina for up to two years with one application.

Integrated management: Integrated management is very important for improving the quality of infested areas. Eradication of crupina on poor areas without revegetation strategies will likely result in colonization of the area by other invasive annuals, such as downy brome (Bromus tectorum). Therefore, reseeding perennial grasses in the fall or spring is important for the long term health and productivity of the land.

References
Belles, W. S., Wattenbarger, D. W. , and Lee, G. A. 1981. Chemical control of Crupina vulgaris, a new range weed in Idaho and the United States. J.Range Manage. 34:468-470.
Couderc-LeVaillant, M. and Roche, C. T. 1993. Evidence of multiple introduction of Crupina vulgaris in infestations in the western United States. Madrono 40:63-65.
Davis, L. H. and Sherman, R. J. 1991. Crupina vulgaris Cass. (Asteraceae: Cynareae), estabilished in Sonoma County, California at Annadel State Park. Madrono 38:296-
Lass, L. W. and Callihan, R. H. 1992. Control of common crupina in advanced growth stages. Res.Prog.Rep.West.Soc.Weed Sci. 45:12-13.
Lass, L. W. and Callihan, R. H. 1992. Effects of herbicides on seed production and survival of common crupina and other plants in a former pasture site. Res.Prog.Rep.West.Soc.Weed Sci. 45:14-15.
Miller, T. and Thill, D. 1983 Today's weed: common crupina (Crupina vulgaris). Weeds Today 14:10-11.
Patterson, D. T. and Mortensen, D. A. 1985. Effects of temperature and photoperiod on common crupina (Crupina vulgaris). Weed Sci. 33:333-339.
Prather, T. S., Callihan, R. H., and Thill, D. C. 1991. Common crupina: biology, management and eradication. Curr.Inf.Ser.Coop.Ext.Serv.Univ.Idaho. (880).
Sobhian, R., Knutson, L., and Rodier, J. S. 1986 Biology and host specificity notes on Styphlus penicillus Gyllenhal (Coleoptera: Curculionidae), examined as a biological control agent for Crupina vulgaris in the United States with remarks on its host plant. Proc.Entomol.Soc.Wash. 98:317-323.
Stickney, P. F. 1972. Crupina vulgaris (Compositae: Cynareae), new to Idaho and North America. Madrono 21:402
Thill, D. C., Zamora, D. L., and Kambitsch, D. L. 1985. Germination and viability of common crupina (Crupina vulgaris) achenes buried in the field. Weed Sci. 33:344-348.
Thill, D. C., Zamora, D. L., and Kambitsch, D. L. 1986. The germination and viability of excreted common crupina (Crupina vulgaris) achenes. Weed Sci. 34:237-241.
Zamora, D. L., Thill, D. C., and Callihan, R. H. 1986. Efficacy of spring applied herbicides on control, density, and biomass of common crupina. Res.Prog.Rep.West.Soc.Weed Sci. 39:19-20.
Zamora, D. L., Thill, D. C., and Callihan, R. H. 1986. Efficacy of sequential applications of selected herbicides on control, density, and yield of common crupina. Res.Prog.Rep.West.Soc.Weed Sci. 39:17-18.
Zamora, D. L. and Thill, D. C. 1987. Preemergence herbicides for control of common crupina. Res.Prog.Rep.West.Soc.Weed Sci. 45-
Zamora, D. L. and Thill, D. C. 1987. Sequential applications of herbicides for control of common crupina. Res.Prog.Rep.West.Soc.Weed Sci. 40:43-44.
Zamora, D. L. and Thill, D. C. 1988 The compatibility of rhodamine B dye with herbicides for common crupina (Crupina vulgaris) control. Weed Technol.J.Weed Sci.Soc.Am. 2:16-19.
Zamora, D. L., Thill, D. C., and Eplee, R. E. Eradication manual for common crupina (Crupina vulgaris Cass.). Bull.Idaho.Agric.Exp.Stn. (701).
Zamora, D. L. and Thill, D. C. 1989 Seed bank longevity of common crupina (Crupina vulgaris) in natural populations. Weed Technol. 3:166-169.
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