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Effect of biocontrol insects on diffuse knapweed (Centaurea diffusa) in a Colorado grassland

Published online by Cambridge University Press:  20 January 2017

T. R. Seastedt ,
Nathan Gregory  and
David Buckner
Nathan Gregory
Affiliation:
Department of Environmental, Population, and Organismic Biology, University of Colorado, Boulder, CO 80309-0334
David Buckner
Affiliation:
ESCO Associates Inc., P.O. Box 18775, Boulder, CO 80308
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Abstract

Four species of biocontrol insects (knapweed root weevil, lesser knapweed flower weevil, spotted knapweed seedhead moth, and bronze knapweed root borer) were released at a diffuse knapweed site located about 10 km east of the Colorado Front Range. Two other biocontrol agents (banded gall fly and knapweed seed head fly) were already present at this site. Densities of rosettes and flowering plants, seedhead production per plant, and seeds per seedhead on mowed and unmowed areas were studied for 5 yr, 1997–2001. Of the six biocontrols, five (Urophora spp., bronze knapweed root borer, knapweed root weevil, and lesser knapweed flower weevil) obtained sizable densities relative to weed abundance. Diffuse knapweed declined from 8.3% in absolute cover in June 2000 to 1.9% by September 2001. Vegetation transects closest to the insect release areas showed the largest declines, with diffuse knapweed disappearing entirely on one transect. In contrast, diffuse knapweed abundance at a nearby prairie increased during the same interval from an absolute cover value of 14.5 to 17%. Seed production of diffuse knapweed on the insect release site declined from nearly 5,000 seeds m−2 in 1997 to less than 100 seeds m−2 in 2001. Lesser knapweed flower weevil larvae appeared responsible for much of the seed reduction, whereas adults of this species were effective in damaging bolting plants. The extent to which grazing removal and individual insect species contributed to this reduction in diffuse knapweed abundance cannot be identified from this study. These results support the contention that a significant reduction in abundance of diffuse knapweed using insects is possible at least in some regions of the western United States.

Keywords

Diffuse knapweed, Centaurea diffusa Lam. CENDIAlyssum, Alyssum minus (L.) Rothm. AYSMIJapanese brome, Bromus japonicus Thunb. Ex. Murr. BROJAfield bindweed, Convolvulus arvensis L. CONARbanded gall fly, Urophora affinis Frauenfeldknapweed seed head fly, Urophora quadrifasciata Meigenbronze knapweed root borer, Sphenoptera jugoslavica Obenb.knapweed root weevil, Cyphocleonus achates Fahraeusspotted knapweed seedhead moth, Metzneria paucipunctella Zell.lesser knapweed flower weevil, Larinus minutus GyllenhalBiological controlcompensatory growthpopulation dynamics

Information

Type
Research Article
Information
Weed Science , Volume 51 , Issue 2 , April 2003 , pp. 237 - 245
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

Beck, K. G. and Rittenhouse, L. R. 2001. The Influence of Cattle Grazing on Diffuse Knapweed. Boulder, CO: Report to City of Boulder Open Space.Google Scholar
Callaway, R. M. 1999. Biological-control herbivores may increase competitive ability of the noxious weed Centaurea maculosa . Ecology 80:1196–1201.Google Scholar
DiTomaso, J. M. 2000. Invasive weeds in rangelands: species, impacts and management. Weed Sci. 48:255–265.Google Scholar
Harris, P. 1980a. Establishment of Urophora affinis Frfld. and U. quadrifasciata (Meig.) (Diptera: Tephritidae) in Canada for the biological control of diffuse and spotted knapweed. Z. Angew. Entomol. 89:504–514.Google Scholar
Harris, P. 1980b. Effects of Urophora affinis Frfld. and U. quadrifasciata (Meig.) (Diptera: Tephritidae) on Centaurea diffusa Lam. and C. maculosa Lam. (Compositae). Z. Angew. Entomol. 90:190–201.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
Lacey, J. R., Marlow, C. B., and Lane, J. R. 1989. Influence of spotted knapweed on surface water runoff and sediment yield. Weed Technol. 3:627–631.Google Scholar
Lang, R. F., Hansen, R. W., Richard, R. D., and Ziolkowski, H. 2000a. Spotted knapweed (Centaurea maculosa Lamarck) seed and Urophora spp. gall destruction by Larinus minutus Gyllenhal (Coleoptera: Curculionidae) combined with Urophora affinis Frauenfeld (Diptera: Tephritidae) and Urophora quadrifasciata (Meigen) (Diptera: Tephritidae). Pages 735–737 In Spencer, N. R., ed. Proceedings of the X International Symposium for Biological Control of Weeds. Bozeman, MT: Montana State University.Google Scholar
Lang, R. F., Richard, R. D., Parker, P. E., and Wendel, L. 2000b. Release and establishment of diffuse and spotted knapweed biocontrol agents by USDA, APHIS, PPQ, in the United States. Pan-Pac. Entomol. 76:197–218.Google Scholar
Mack, R. N., Simberloff, D., Lonsdale, W. M., Evans, H., Clout, M., and Bazzaz, F. 2000. Biotic invasions: causes, epidemiology, global consequences, and control. Ecol. Appl. 10:689–710.Google Scholar
Maddox, D. M. 1979. The knapweeds: their economics and biological control in the western states, USA. Rangelands 1:139–141.Google Scholar
McEvoy, P. B. and Coombs, E. M. 1999. Biological control of plant invaders: regional patterns, field experiments, and structured population models. Ecol. Appl. 9:387–401.Google Scholar
Moreland, D. C. and Moreland, R. E. 1975. Soil Survey of the Boulder County Area, CO. USDA Soil Conservation Service. Fort Collins, CO: Colorado Agricultural Experiment Station Report.Google Scholar
Muller-Scharer, H. and Schroeder, D. 1993. The biological control of Centaurea spp. in North America: do insects solve the problem? Pestic. Sci. 37:343–353.Google Scholar
Myers, J. H., Risley, C., and Eng, R. 1990. The ability of plants to compensate for insect attack: Why biological control of weeds with insects is so difficult. Pages 67–73 In Delfosse, E. S., ed. Proceedings of the VII International Symposium for Biological Control of Weeds; 1988. Rome: Instituto Sperimentale per la Patologia Vegetale, M.A.F.Google Scholar
NOAA. 2002. Climate Diagnostics Center, National Oceanic and Atmospheric Administration. Boulder Monthly Means: Precipitation. Available at http://www/cdc/noaa.gov/Boulder/Boulder.mm.precip.html. Accessed: 21 July 2002.Google Scholar
Powell, R. D. and Myers, J. H. 1988. The effects of Sphenoptera jugoslavica Obenb. (Col., Buprestidae) on its host plant, Centaurea diffusa Lam. (Compositae). J. Appl. Entomol. 106:24–45.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 Agricultural Research Service, Montana Department of Agriculture. Bozeman, MT: Montana State University.Google Scholar
Roche, B. F. and Roche, C. T. 1998. Diffuse knapweed. Pages 217–230 In Sheley, R. L. and Petroff, J. K., eds. Biology and Management of Noxious Rangeland Weeds. Corvallis, OR: Oregon State University Press.Google Scholar
[SAS] Statistical Analysis Systems. 1988. SAS/STAT User's Guide. Release 6.03 Edition. Cary, NC: Statistical Analysis Systems Institute. 1028 p.Google Scholar
Sheley, R. L., Jacobs, J. S., and Carpinelli, M. F. 1998. Distribution, biology and management of diffuse knapweed (Centaurea diffusa) and spotted knapweed (Centaurea maculosa). Weed Technol. 12:353–362.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
Watson, A. K. and Renney, A. J. 1974. The biology of Canadian weeds. Can. J. Plant Sci. 54:687–701.Google Scholar
Wester, D. B. 1992. Replication, randomization, and statistics in range research. J. Range Manag. 45:285–290.Google Scholar
Woodall, C., Handler, A., and Broberg, L. 2000. Social dilemmas in grassland ecosystem restoration. Ecol. Restor. 18:39–44.Google Scholar