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Downy Brome (Bromus tectorum) Control with Imazapic on Montana Grasslands

  • Jane Mangold (a1), Hilary Parkinson (a1), Celestine Duncan (a2), Peter Rice (a3), Ed Davis (a1) and Fabian Menalled (a1)...

Downy brome is a problematic invasive annual grass throughout western rangeland and has been increasing its abundance, spread, and impacts across Montana during the past several years. In an effort to develop effective management recommendations for control of downy brome on Montana rangeland, we compiled data from 24 trials across the state that investigated efficacy of imazapic (Plateau®, BASF Corporation, Research Triangle Park, NC) applied at various rates and timings and with methylated seed oil (MSO) or a nonionic surfactant (NIS). We ran a mixed-model ANOVA to test for main effects and interactions across application rate (70, 105, 141, 176, and 211 g ai ha−1), application timing (preemergent [PRE], early postemergent [EPOST, one- to two-leaf growth stage], and postemergent [POST, three- to four-leaf growth stage]), and adjuvant (MSO, NIS). Application timing and rate interacted to affect downy brome control (P = 0.0033). PRE imazapic application resulted in the lowest downy brome control (5 to 19%), followed by POST application (25 to 77%) and EPOST application (70 to 95%). Downy brome control remained fairly consistent across rates within application timing. Adjuvant (MSO or NIS) did not affect downy brome control (P = 0.2789). Our data indicate that POST application at 105 to 141 g ai ha−1 provides the most-consistent, short-term control of downy brome. Furthermore, applying imazapic to downy brome seedlings shortly after emergence (one- to two-leaf growth stage) provided better control than applying it to older downy brome seedlings (three- to four-leaf growth stage).

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Anonymous, . 2008. Plateau® herbicide product label. BASF Publication No. NVA 2011-04-126-0007. Research Triangle Park, NC BASF. 15 p.
Baker, W. L., Garner, J., and Lyon, P. 2009. Effect of imazapic on cheatgrass and native plants in Wyoming big sagebrush restoration for Gunnison sage-grouse. Nat. Areas J. 29:204209.
Calo, A., Brause, S., and Jones, S. 2012. Integrated treatment with a prescribed burn and postemergent herbicide demonstrates initial success in management cheatgrass in a northern Colorado natural area. Nat. Areas J. 32:300304.
Davies, K. W. and Sheley, R. L. 2011. Promoting native vegetation and diversity in exotic annual grass infestations. Restor. Ecol. 19:159165.
Davison, J. C. and Smith, E. G. 2007. Imazapic provides 2-year control of weedy annuals in a seeded Great Basin fuelbreak. Native Plants J. 8:9195.
Diamond, J. M., Call, C. A., and Devoe, N. 2012. Effects of targeted grazing and prescribed burning on community and seed dynamics of a downy brome (Bromus tectorum)- dominated landscape. Inv. Plant Sci. Manag. 5:259269.
Elseroad, A. C. and Rudd, N. T. 2011. Can imazapic increase native species abundance in cheatgrass (Bromus tectorum) invaded native plant communities? Rangeland Ecol. Manag. 64:641648.
Epanchin-Niell, R., Englin, J., and Nalle, D. 2009. Investing in rangeland restoration in the arid west, USA: countering the effects of an invasive weed on the long-term fire cycle. J. Environ. Manag. 91:370379.
Geier, P. W., Stahlman, P. W., Northam, F. E., Miller, S. D., and Hageman, N. R. 1998. MON 37500 rate and timing affects downy brome (Bromus tectorum) control in winter wheat (Triticum aestivum). Weed Sci. 46:366373.
Grichar, W. J. and Sestak, D. C. 2000. Effects of adjuvants on control of nutsedge (Cyperus esculentus and C. rotundus) by imazapic and imazethapyr. Crop Prot. 19:461465.
Kyser, G. B., DiTomaso, J. M., Doran, M. P., Orloff, S. B., Wilson, R. G., Lancaster, D. L., Lile, D. F., and Porath, M. L. 2007. Control of medusahead (Taeniatherum caput-medusae) and other annual grasses with imazapic. Weed Technol. 21:6675.
Markle, D. M. and Lym, R. G. 2001. Leafy spurge (Euphorbia esula) control and herbage production with imazapic. Weed Technol. 5:474480.
Menalled, F., Mangold, J., and Davis, E. 2008. Cheatgrass: Identification, Biology and Integrated Management. MontGuide. MT200811AG. Bozeman, MT Montana State University Extension.
Meyer, S. E., Quinney, D., Nelson, D. L., and Weaver, J. 2007. Impact of the pathogen Pyrenophora semeniperda on Bromus tectorum seedbank dynamics in North American cold deserts. Weed Technol. 47:5462.
Morris, C., Monaco, T., and Rigby, C. W. 2009. Variable impacts of imazapic rate on downy brome (Bromus tectorum) and seeded species in two rangeland communities. Inv. Plant Sci. Manag. 2:110119.
Owen, S. M., Sieg, C. H., and Gehring, C. A. 2011. Rehabilitating downy brome (Bromus tectorum)—invaded shrublands using imazapic and seeding with native shrubs. Inv. Plant Sci. Manag. 4:223233.
Pinheiro, J., Bates, D., DebRoy, S., and Sarkar, D. 2011. R Development Core Team, nlme: Linear and Nonlinear Mixed Effects Models. Wien, Austria R Foundation for Statistical Computing R package, Version 3.1–102.
Radosevich, S. R., Holt, J. S., and Ghersa, C. M. 2007. Ecology of Weeds and Invasive Plants, 3rd ed. Hoboken, NJ J. Wiley. 454 p.
Rice, P. M. 2005. Downy brome. Pages 147170 in Duncan, C. L. and Clark, J. K., eds. Invasive Plants of Range and Wildlands and Their Environmental, Economic, and Societal Impacts. Lawrence, KS Weed Science Society of America.
Ross, M. A. and Lembi, C. A. 1985. Applied Weed Science. Minneapolis, MN Burgess. 340 p.
Sheley, R. L., Carpinelli, M. F., and Reever-Morghan, K. J. 2007. Effects of imazapic on target and nontarget vegetation during revegetation. Weed Technol. 21:10711081.
Smith, R. G., Maxwell, B. D., Menalled, F. D., and Rew, L. J. 2006. Lessons from agriculture may improve the management of invasive plants in wildland systems. Front. Ecol. Environ. 4:428434.
Stougaard, R. N., Mallory-Smith, C. A., and Mickelson, J. A. 2004. Downy brome (Bromus tectorum) response to imazamox rate and application timing in herbicide-resistant winter wheat. Weed Technol. 18:10431048.
Whitson, T. D. and Koch, D. W. 1998. Control of downy brome (Bromus tectorum) with herbicides and perennial grass competition. Weed Technol. 12:391396.
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Invasive Plant Science and Management
  • ISSN: 1939-7291
  • EISSN: 1939-747X
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