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Canada Thistle (Cirsium arvense) Response to Simulated Insect Defoliation and Plant Competition
- Ban N. Ang, Loke T. Kok, Golde I. Holtzman, Dale D. Wolf
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- Journal:
- Weed Science / Volume 42 / Issue 3 / September 1994
- Published online by Cambridge University Press:
- 12 June 2017, pp. 403-410
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The combined influence of plant competition and defoliation on development of Canada thistle was investigated in a 2-yr field study. Plant competition was induced by seeding tall fescue and crown vetch. Artificial defoliation was used to simulate various levels of leaf removal by insects. Both defoliation and induced competition reduced biomass of Canada thistle but their impact varied with environmental conditions. Defoliation had a greater detrimental influence than induced competition on thistle biomass in a dry year when growth of the plant competitors was suppressed. In a wet year, induced competition was more important in suppressing Canada thistle than defoliation, and moderate levels of defoliation (25%), applied once when the thistles were 12 to 15 cm in diam, stimulated root weight within the top 20 cm of soil. Reduction in thistle biomass increased with level of defoliation and was greatest when defoliation was applied repeatedly at 14-d intervals in the presence of induced competition. Crown vetch showed very little growth in one season and tall fescue was the primary source of competition for the thistles. The results confirm the hypothesis that combined stresses can substantially reduce biomass development of Canada thistle plants.
Weed Suppression in No-Till Alfalfa (Medicago sativa) by Prior Cropping of Summer-Annual Forage Grasses
- D. Raymond Forney, Chester L. Foy, Dale D. Wolf
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- Journal:
- Weed Science / Volume 33 / Issue 4 / July 1985
- Published online by Cambridge University Press:
- 12 June 2017, pp. 490-497
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A sorghum-sudangrass hybrid [Sorghum bicolor (L.) Moench. x Sorghum sudanense (P.) Stapf. ‘DEKALB SX17+’] (SSH) and foxtail millet [Setaria italica (L.) Beauv.] (FM) were evaluated for their effects on weed populations when grown for forage and as land conditioners prior to late-summer, no-till planting of alfalfa (Medicago sativa L. ‘Arc’). Both grasses established well in no-till situations, except for FM when excessive mulch impeded seed placement or seedling summer-annual weeds were not destroyed at planting time. SSH was the better competitor; after both were planted into a dense stand of seedling summer-annual weeds, SSH outyielded the weeds while FM did not. Both grasses suppressed weeds and enhanced subsequent alfalfa establishment. Obtaining adequate alfalfa stands was not a problem in no-till seedings: seedling populations often exceeded 300/m2 3 to 6 weeks after planting. Lack of adequate weed control was associated with stand losses in which disease was also a factor. Biennial and perennial broadleaf species were the predominant weeds. Prior cropping of SSH or FM is a valuable option for growers wishing to establish alfalfa without tillage, particularly when summer forage is useful.
Looking Backward, Looking Forward: MLA Members Speak
- April Alliston, Elizabeth Ammons, Jean Arnold, Nina Baym, Sandra L. Beckett, Peter G. Beidler, Roger A. Berger, Sandra Bermann, J.J. Wilson, Troy Boone, Alison Booth, Wayne C. Booth, James Phelan, Marie Borroff, Ihab Hassan, Ulrich Weisstein, Zack Bowen, Jill Campbell, Dan Campion, Jay Caplan, Maurice Charney, Beverly Lyon Clark, Robert A. Colby, Thomas C. Coleman III, Nicole Cooley, Richard Dellamora, Morris Dickstein, Terrell Dixon, Emory Elliott, Caryl Emerson, Ann W. Engar, Lars Engle, Kai Hammermeister, N. N. Feltes, Mary Anne Ferguson, Annie Finch, Shelley Fisher Fishkin, Jerry Aline Flieger, Norman Friedman, Rosemarie Garland-Thomson, Sandra M. Gilbert, Laurie Grobman, George Guida, Liselotte Gumpel, R. K. Gupta, Florence Howe, Cathy L. Jrade, Richard A. Kaye, Calhoun Winton, Murray Krieger, Robert Langbaum, Richard A. Lanham, Marilee Lindemann, Paul Michael Lützeler, Thomas J. Lynn, Juliet Flower MacCannell, Michelle A. Massé, Irving Massey, Georges May, Christian W. Hallstein, Gita May, Lucy McDiarmid, Ellen Messer-Davidow, Koritha Mitchell, Robin Smiles, Kenyatta Albeny, George Monteiro, Joel Myerson, Alan Nadel, Ashton Nichols, Jeffrey Nishimura, Neal Oxenhandler, David Palumbo-Liu, Vincent P. Pecora, David Porter, Nancy Potter, Ronald C. Rosbottom, Elias L. Rivers, Gerhard F. Strasser, J. L. Styan, Marianna De Marco Torgovnick, Gary Totten, David van Leer, Asha Varadharajan, Orrin N. C. Wang, Sharon Willis, Louise E. Wright, Donald A. Yates, Takayuki Yokota-Murakami, Richard E. Zeikowitz, Angelika Bammer, Dale Bauer, Karl Beckson, Betsy A. Bowen, Stacey Donohue, Sheila Emerson, Gwendolyn Audrey Foster, Jay L. Halio, Karl Kroeber, Terence Hawkes, William B. Hunter, Mary Jambus, Willard F. King, Nancy K. Miller, Jody Norton, Ann Pellegrini, S. P. Rosenbaum, Lorie Roth, Robert Scholes, Joanne Shattock, Rosemary T. VanArsdel, Alfred Bendixen, Alarma Kathleen Brown, Michael J. Kiskis, Debra A. Castillo, Rey Chow, John F. Crossen, Robert F. Fleissner, Regenia Gagnier, Nicholas Howe, M. Thomas Inge, Frank Mehring, Hyungji Park, Jahan Ramazani, Kenneth M. Roemer, Deborah D. Rogers, A. LaVonne Brown Ruoff, Regina M. Schwartz, John T. Shawcross, Brenda R. Silver, Andrew von Hendy, Virginia Wright Wexman, Britta Zangen, A. Owen Aldridge, Paula R. Backscheider, Roland Bartel, E. M. Forster, Milton Birnbaum, Jonathan Bishop, Crystal Downing, Frank H. Ellis, Roberto Forns-Broggi, James R. Giles, Mary E. Giles, Susan Blair Green, Madelyn Gutwirth, Constance B. Hieatt, Titi Adepitan, Edgar C. Knowlton, Jr., Emanuel Mussman, Sally Todd Nelson, Robert O. Preyer, David Diego Rodriguez, Guy Stern, James Thorpe, Robert J. Wilson, Rebecca S. Beal, Joyce Simutis, Betsy Bowden, Sara Cooper, Wheeler Winston Dixon, Tarek el Ariss, Richard Jewell, John W. Kronik, Wendy Martin, Stuart Y. McDougal, Hugo Méndez-Ramírez, Ivy Schweitzer, Armand E. Singer, G. Thomas Tanselle, Tom Bishop, Mary Ann Caws, Marcel Gutwirth, Christophe Ippolito, Lawrence D. Kritzman, James Longenbach, Tim McCracken, Wolfe S. Molitor, Diane Quantic, Gregory Rabassa, Ellen M. Tsagaris, Anthony C. Yu, Betty Jean Craige, Wendell V. Harris, J. Hillis Miller, Jesse G. Swan, Helene Zimmer-Loew, Peter Berek, James Chandler, Hanna K. Charney, Philip Cohen, Judith Fetterley, Herbert Lindenberger, Julia Reinhard Lupton, Maximillian E. Novak, Richard Ohmann, Marjorie Perloff, Mark Reynolds, James Sledd, Harriet Turner, Marie Umeh, Flavia Aloya, Regina Barreca, Konrad Bieber, Ellis Hanson, William J. Hyde, Holly A. Laird, David Leverenz, Allen Michie, J. Wesley Miller, Marvin Rosenberg, Daniel R. Schwarz, Elizabeth Welt Trahan, Jean Fagan Yellin
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- Journal:
- PMLA / Publications of the Modern Language Association of America / Volume 115 / Issue 7 / December 2000
- Published online by Cambridge University Press:
- 23 October 2020, pp. 1986-2078
- Print publication:
- December 2000
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