Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-28T14:27:57.477Z Has data issue: false hasContentIssue false
  • English
  • Français

Tolerance of Several Perennial Grasses to Imazapic

Published online by Cambridge University Press:  20 January 2017

Sandra L. Shinn  and
Donald C. Thill
Sandra L. Shinn*
Affiliation:
Syngenta Crop Protection, 67 Pinewood Road, Hudson, NY 12534
Donald C. Thill
Affiliation:
Syngenta Crop Protection, 67 Pinewood Road, Hudson, NY 12534
*
Corresponding author's E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Although some herbicides are available for control of broadleaf weeds on rangeland, currently no herbicides are registered for selective control of weedy annual grasses in perennial forage grasses. Field experiments were conducted to determine the tolerance of several perennial forage grass species to preemergence (PRE) and postemergence (POST) applications of imazapic, a herbicide that controls certain weedy annual grasses. In PRE studies, perennial forage grasses were seeded 1 d after spraying with several rates of imazapic. The grass species by herbicide rate by location and the grass species by herbicide rate interactions were not significant for plant height and biomass 395 d after treatment (DAT). Expressed as a percentage of the untreated control, imazapic applied at 18 to 140 g/ha reduced height of all grass species 10 to 18%, whereas 280 g/ha of imazapic reduced height 39%. Imazapic applied at 18 to 70 g/ha reduced biomass 12 to 26%. Biomass was reduced 51 and 63% when imazapic was applied at 140 and 280 g/ha, respectively. Thus, rates of imazapic required to control downy brome likely will excessively injure perennial forage grass seeded 1 DAT. In POST studies, imazapic was applied to 1-yr-old stands of perennial forage grass. A dose– response model provided a good fit for grass species biomass and height data. In year 1, biomass and height of orchardgrass, smooth brome, and meadow brome were reduced 14 to 29% more than those of bluebunch, crested, intermediate, and western wheatgrass as imazapic rate increased, which implies that the wheatgrasses were more tolerant to imazapic. However, in year 2, slope of regression lines did not differ among grass species, implying that all forage grass species responded the same to increasing rates of imazapic. Plant height of all grass species decreased 25 to 56% when compared with the untreated control, and biomass decreased 28 to 59% as imazapic rate increased from 18 to 280 g/ha. As discussed previously, rates of spring-applied imazapic required for downy brome control severely injured perennial forage grasses whether applied PRE or POST. The level of tolerance of perennial forage grasses to imazapic depended on herbicide dose and perhaps environmental differences between years.

Keywords

Imazapicbluebunch wheatgrass, Agropyron spicatum (Pursh) Scribn. & Smith. #3 AGRSPcrested wheatgrass, Agropyron cristatum (L.) Gaertn. # AGRCRdowny brome, Bromus tectorum L. # BROTEintermediate wheatgrass, Agropyron intermedium (Host) Beauv. # AGRINmeadow brome, Bromus erectus Huds. # BROERorchardgrass, Dactylis glomerata L. # DACGLsmooth brome, Bromus inermis Leyss. # BROINwestern wheatgrass, Pascopyrum smithii Rydb. # PASSMBiomasspicloramplant densitytoleranceDAT, days after treatmentOM, organic matterPOST, postemergencePP, preplantPRE, preemergence
Type
Research
Information
Weed Technology , Volume 18 , Issue 1 , March 2004 , pp. 60 - 65
Copyright
Copyright © 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.)

References

Literature Cited

Daubenmire, R. F. 1970. Steppe Vegetation of Washington. Pullman, WA: Washington Agricultural Experiment Station Technical Bulletin 62. 131 p.Google Scholar
Evans, R. A. 1961. Effects of different densities of downy brome (Bromus tectorum) on growth and survival of crested wheatgrass (Agropyron desertorum) in the greenhouse. Weed Sci. 9:216–223.Google Scholar
Harris, G. A. 1967. Some competitive relationship between Agropyron spictum and Bromus tectorum . Ecol. Monogr 37:89–111.Google Scholar
Heath, M. E., Barnes, R. F., and Metcalfe, D. S. 1985. Forages: the science of grassland agriculture. in Buckner, R. C., ed. The Fescues. Ames, IA: Iowa State University Press. Pp. 233–240.Google Scholar
Hull, A. C. Jr. 1963. Competition and water requirements of cheatgrass and wheatgrasses in the greenhouse. J. Range Manage 16:199–203.Google Scholar
Idaho Climatological Data. 1999. Web page: http://snow.ag.uidaho.edu/climate/download.html. Accessed: May–June 1999.Google Scholar
Idaho Climatological Data. 2000. Web page: http://snow.ag.uidaho.edu/climate/download.html. Accessed: May–June 2000.Google Scholar
Johnson, D. A. and Aguirre, L. 1991. Effect of water on morphological development in seedlings of three range grasses: root branching patterns. J. Range Manage 44:355–360.Google Scholar
Morrow, L. A. and Stahlman, P. W. 1984. The history and distribution of downy brome (Bromus tectorum) in North America. Weed Sci. 32:2–5.Google Scholar
Shaner, D. L. and O'Conner, S. L. 1991. The imidazolinone herbicides. in Malefyt, T. and Quakenbush, L., eds. Influence of Environmental Factors on the Biological Activity of the Imidazolinone Herbicides. Boca Raton, FL: CRC Press. Pp. 103–127.Google Scholar
Sharp, L. A. and Sanders, K. D. 1978. Rangeland Resources of Idaho. Moscow, ID: University of Idaho. Pp. 4–53.Google Scholar
Shinn, S. L. 2003. The response of yellow starthistle, spotted knapweed, meadow hawkweed to imazapic. Weed Technol. 16:366–370.Google Scholar
Stubbendieck, J., Hatch, S. L., and Butterfield, C. H. 1997. North American Range Plants. Lincoln, NE: University of Nebraska Press. Pp. 184–191.Google Scholar
Svejcar, T. 1990. Root length, leaf area, and biomass of crested wheatgrass and cheatgrass seedlings. J. Range Manage 43:446–448.CrossRefGoogle Scholar
Whitson, T. D. and Koch, D. W. 1998. Control of downy brome (Bromus tectorum) with herbicides and perennial grass competition. Weed Technol. 12:391–396.Google Scholar