Hostname: page-component-669899f699-qzcqf Total loading time: 0 Render date: 2025-04-29T19:51:27.410Z Has data issue: false hasContentIssue false
  • English
  • Français

Distribution, Biology, and Management of Diffuse Knapweed (Centaurea diffusa) and Spotted Knapweed (Centaurea maculosa)

Published online by Cambridge University Press:  12 June 2017

Roger L. Sheley ,
James S. Jacobs  and
Michael F. Carpinelli
Roger L. Sheley
Affiliation:
Plant, Soil and Environmental Science, Montana State University, Bozeman, MT 59717-3120
James S. Jacobs
Affiliation:
Plant, Soil and Environmental Science, Montana State University, Bozeman, MT 59717-3120
Michael F. Carpinelli
Affiliation:
Plant, Soil and Environmental Science, Montana State University, Bozeman, MT 59717-3120
Get access Rights & Permissions [Opens in a new window]

Abstract

Diffuse knapweed, a biennial or short-lived perennial, and spotted knapweed, a perennial, are taprooted Eurasian weeds invading rangeland in the western United States and Canada. Knapweed (Centaurea spp.) invasion is associated with reductions in biodiversity, wildlife, and livestock forage, and increased erosion. Spotted knapweed grows to about 1 m and usually has purple flowers, whereas diffuse knapweed is slightly shorter, usually with white flowers. Persistent flower bracts on diffuse knapweed bear a rigid terminal spine about 8 mm long with four or five pairs of shorter lateral spines. Bracts on spotted knapweed have dark spotted tips. Knapweed management involves a combination of containing infestations and control efforts. Hand pulling in areas with small infestations can be effective for controlling spotted and diffuse knapweeds. Picloram applied at 0.28 kg ha−1 provides control for about 3 yr. Effective long-term control of knapweeds requires periodic applications of picloram, which are only cost-effective on highly productive range sites with a residual grass understory. About 12 insect species have been released for knapweed biocontrol. Seed production has been reduced by 46% by insects feeding in the flower heads. Although insects have not reduced spotted knapweed densities, they may stress the weed and shift the competitive balance to associated species. Sheep grazing reduces the density of very young seedlings and may limit seedling recruitment into the population. In areas without a residual understory of desired plant species, revegetation of knapweed-infested rangeland is required. Components of any integrated weed management program are sustained effort, constant evaluation, and the adoption of improved strategies.

Keywords

Picloram, 4-amino-3,5,6-trichloro-2-pyridinecarboxylic aciddiffuse knapweed, Centaurea diffusa Lam. #3 CENDIspotted knapweed, Centaurea maculosa Lam. # CENMANoxious rangeland weedsintegrated weed managementsustainable weed managementCENDICENMA
Type
Symposium
Information
Weed Technology , Volume 12 , Issue 2 , June 1998 , pp. 353 - 362
Copyright
Copyright © 1998 by the Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Literature Cited

Atkinson, T. G. and Brink, V. C. 1953. Progress Report on the Biology and Control of Diffuse Knapweed (Centaurea diffusa Lam.) in British Columbia. Vancouver, BC: University of British Columbia.Google Scholar
Boggs, K. W. and Story, J. M. 1987. The population age structure of spotted knapweed (Centaurea maculosa) in Montana. Weed Sci. 35:194–198.CrossRefGoogle Scholar
Borman, M. M., Krueger, W. C., and Johnson, D. E. 1991. Effects of established perennial grass on yields of associated annual weeds. J. Range Manage. 44:318–326.CrossRefGoogle Scholar
Cooksey, D. and Sheley, R. 1996. Montana Noxious Weed Survey and Mapping System. Montana State University Cooperative Extension Service MontGuide 9613. 4 p.Google Scholar
Davis, E. S. 1990. Spotted Knapweed (Centaurea maculosa Lam.) Seed Longevity, Chemical Control and Seed Morphology. . Montana Slate University, Bozeman, MT. 109 p.Google Scholar
Davis, E. S., Fay, P. K., Chincoine, T. K., and Lacey, C. A. 1993. Persistence of spotted knapweed (Centaurea maculosa) seed in soil. Weed Sci. 41:57–61.Google Scholar
Fletcher, R. A. 1961. A Growth Inhibitor Found in Centaurea spp. . University of British Columbia, Vancouver, BC.Google Scholar
Fletcher, R. A. and Renny, A. J. 1963. A growth inhibitor found in Centaurea spp. Can. J. Plant Sci. 43:475–481.Google Scholar
Forcella, F. and Harvey, S. J. 1980. New and Exotic Weeds of Montana. II: Migration and Distribution of 100 Alien Weeds in Northwestern USA, 1881–1980. Bozeman, MT: Montana State University Herbarium. 117 p.Google Scholar
Ford, E. J. 1989. Sclerotinia as a mycoherbicide. In Fay, P. K. and Lacey, J. R., eds. Knapweed Symposium Proceedings. Bozeman, MT: Montana State University. pp. 182–189.Google Scholar
Griffith, D. and Lacey, J. R. 1991. Economic evaluation of spotted knapweed (Centaurea maculosa) control using picloram. J. Range Manage. 44:42–44.Google Scholar
Groh, H. 1944. Canadian Weed Survey. 2nd Annual Report. Canada Department of Agriculture. 74 p.Google Scholar
Hakim, S.E.A. 1979. Range Condition on the Threemile Game Range in Western Montana. . University of Montana, Missoula, MT. 62 p.Google Scholar
Harris, P. and Cranston, R. 1979. An economic evaluation of control methods for diffuse and spotted knapweed in western Canada. Can J. Plant Sci. 59:375–382.CrossRefGoogle Scholar
Howell, J. T. 1959. Distributional data on weedy thistles in western North America. Leafl. West. Bot. 9:17–32.Google Scholar
Hubbard, W. A. 1975. Increased range forage production by reseeding and the chemical control of knapweed. J. Range Manage. 28:406–407.Google Scholar
Jacobs, J. S. and Sheley, R. L. 1997. Relationship among Idaho fescue defoliation, soil water, and spotted knapweed emergence and growth. J. Range Manage. 50:258–262.Google Scholar
Jacobs, J. S., Sheley, R. L., and Maxwell, B. D. 1996. Effect of Sclerotinia sclerotiorum on the interference between bluebunch wheatgrass (Agropyron spicatum) and spotted knapweed (Centaurea maculosa). Weed Technol. 10:13–21.CrossRefGoogle Scholar
James, D. 1992. Some principles and practices of desert revegetation seeding. Arid Lands Newsl. 32:22–27.Google Scholar
Kearing, S. A. and Nowierski, R. M. 1997. First report of stem and bud blight by Pseudomonas syringae pv. Syringae on spotted knapweed (Centaurea maculosa Lam.). Plant Dis. 81:113.Google Scholar
Kelsey, R. G. and Locken, L. J. 1987. Phytotoxic properties of cnicin, a sequiterpene lactone from Centaurea maculosa (spotted knapweed). J. Chem. Ecol. 13:19–33.Google Scholar
Kelsey, R. G. and Mihalovich, R. D. 1987. Nutrient composition of spotted knapweed (Centaurea maculosa). J. Range Manage. 40:277–281.CrossRefGoogle Scholar
Kennet, G. A., Lacey, J. R., Butt, C. A., Olson-Rutz, K. M., and Haferkamp, M. R. 1992. Effects of defoliation, shading and competition on spotted knapweed and bluebunch wheatgrass. J. Range Manage. 45:363–369.Google Scholar
Lacey, C. A., Lacey, J. R., Fay, P. K., Story, J. M., and Zamora, D. L. 1995. Controlling Knapweed in Montana Rangeland. Montana State University Cooperative Extension Service Circ. 311. 17 p.Google Scholar
Lacey, J., Husby, P., and Handl, G. 1990. Observations on spotted and diffuse knapweed invasion into ungrazed bunchgrass communities in western Montana. Rangelands 12:30–32.Google Scholar
Lacey, J. R., Marlow, C. B., and Lane, J. R. 1989. Influence of spotted knapweed (Centaurea maculosa) on surface water runoff and sediment yield. Weed Technol. 3:627–631.CrossRefGoogle Scholar
Larson, L. L. and McInnis, M. L. 1989. Impact of grass seedlings on establishment and density of diffuse knapweed and yellow starthistle. Northwest Sci. 63:162–166.Google Scholar
Locken, L. J. and Kelsey, R. G. 1987. Cnicin concentrations in Centaurea maculosa (spotted knapweed). Biochem. Syst. Ecol. 15:313–320.Google Scholar
Muller, H., Schroeder, D., and Gassmann, A. 1988. Agapeta zoegana (L.) (Lepidoptera: Cochylidae), a suitable prospect for biological control of spotted and diffuse knapweed, Centaurea maculosa Monnet De La Marck and Centaurea diffusa Monnet De La Marck (Compositae) in North America. Can. Entomol. 120:109–124.CrossRefGoogle Scholar
Myers, J. H. and Berube, D. E. 1983. Diffuse knapweed invasion into rangeland in the dry interior of British Columbia. Can. J. Plant Sci. 63:981–987.CrossRefGoogle Scholar
Nolan, D. G. and Upadhyaya, M. K. 1988. Primary seed dormancy in diffuse and spotted knapweed. Can. J. Plant Sci. 68:775–783.Google Scholar
Olson, B. E., Wallander, R. T., and Lacey, J. R. 1997. Effects of sheep grazing on a spotted knapweed-infested Idaho fescue community. J. Range Manage. 50:386–390.Google Scholar
Popova, A. 1960. Centaurea diffusa Lam., a steppe pasture weed in the Crimea. Bot. Zh. (Moscow) 45:1207–1213. [English translation]Google Scholar
Rees, N. E., Quimby, P. C. Jr., Piper, G. L., Coombs, E. M., Turner, C. E., Spencer, N. R., and Knutson, L. V. 1996. Biological Control of Weeds in the West. Western Society of Weed Science, USDA-ARS. Bozeman, MT: Montana State University. 144 p.Google Scholar
Renny, A. J. and Hughes, E. C. 1969. Control of knapweed Centaurea species in British Columbia with Tordon herbicides. Down Earth 24:6–8.Google Scholar
Roché, B. F., Piper, G. L., and Talbott, C. J. 1986. Knapweeds of Washington. Washington State University Cooperative Extension Service Bull. EB1393. 41 p.Google Scholar
Roché, B.F. Jr., and Talbott, C. J. 1986. The Collection History of Centaurea Found in Washington State. Agricultural Research Center Research Bull. XBO978. Pullman, WA: Washington State University Cooperative Extension Service. 36 p.Google Scholar
Roché, C.T. and Roch, B. F.é. 1993. Identification of Knapweeds and Star-thistles in the Pacific Northwest. Pacific Northwest Extension Pub. PNW432. 22 p.Google Scholar
Sheley, R., Manoukian, M., and Marks, G. 1996a. Preventing noxious weed invasion. Rangelands 18:100–101.Google Scholar
Sheley, R. L. and Jacobs, J. S. 1997. Response of spotted knapweed and grass to picloram and fertilizer combinations. J. Range Manage. 50:263–267.Google Scholar
Sheley, R. L. and Larson, L. L. 1996. Emergence date effects on resource partitioning between diffuse knapweed seedlings. J. Range Manage. 49:241–244.Google Scholar
Sheley, R. L., Olson, B. E., and Larson, L. L. 1997. Effect of weed seed rate and grass defoliation level on diffuse knapweed. J. Range Manage. 50:39–43.Google Scholar
Sheley, R. L. and Roché, B. F. Jr. 1982. Rehabilitation of spotted knapweed infested rangeland in northeastern Washington. West. Soc. Weed Sci. Abstr. p. 31.Google Scholar
Sheley, R. L., Svejcar, T. J., and Maxwell, B. D. 1996b. A theoretical framework for developing successional weed management strategies on rangeland. Weed Technol. 10:712–720.Google Scholar
Shirman, R. 1981, Seed production and spring seedling establishment of diffuse and spotted knapweed. J. Range Manage. 34:45–47.Google Scholar
Spoon, C. W., Bowles, H. R., and Kulla, A. 1983. Noxious Weeds on the Lolo National Forest. A Situation Analysis Staff Paper. Missoula, MT: U.S. Department of Agriculture Forest Service. 33 p.Google Scholar
Story, J. M., Boggs, K. W., Good, W. R., and Nowierski, R. M. 1989. The seed moth, Metzneria paucipuntella: its impact on spotted knapweed seed production and two seedhead slies, Urophora spp. In Fay, P. K. and Lacey, J. R., eds. Proceedings of the Knapweed Symposium. Bozeman, MT: Montana State University. pp. 172–174.Google Scholar
Strang, R. M., Lindsay, K. M., and Price, R. S. 1979. Knapweeds: British Columbia's undesirable aliens. Rangelands 1:141–143.Google Scholar
Tyser, R. W. and Key, C. H. 1988. Spotted knapweed in natural area fescue grasslands: an ecological assessment. Northwest Sci. 62:981–987.Google Scholar
Velagala, R. P. 1996. Using Seed Rate and Plant Densities to Enhance Intermediate Wheatgrass Establishment in Spotted Knapweed Dominated Rangeland. . Montana State University, Bozeman, MT. 66 p.Google Scholar
Velagala, R. P., Sheley, R. L., and Jacobs, J. S. 1997. Influence of density on intermediate wheatgrass and spotted knapweed interference. J. Range Manage. 50:523–529.Google Scholar
Wallander, R. T., Olson, B. E., and Lacey, J. R. 1995. Spotted knapweed seed viability after passing through sheep and mule deer. J. Range Manage. 48:145–149.Google Scholar
Watson, A. K. and Renny, A. J. 1974. The biology of Canadian weeds. 6. Centaurea diffusa and C. Maculosa . Can. J. Plant Sci. 54:687–701.CrossRefGoogle Scholar