Skip to main content
×
Home
    • Aa
    • Aa

Imazapic Activity in a Semiarid Climate in Downy Brome (Bromus tectorum)–Infested Rangeland and CRP Sites

  • Krista A. Ehlert (a1), Richard E. Engel (a1) and Jane M. Mangold (a1)
Abstract

Chemical control of downy brome has focused on imazapic; however, imazapic efficacy in semiarid climates is unpredictable, possibly because of variable residual soil activity. Our objective was to characterize imazapic activity over 9 mo in rangeland and a Conservation Reserve Program (CRP) site following its application in the fall as affected by rate (0, 80, 160, 240 g ai ha−1) and quantity of plant residue (reduced, ambient). Greenhouse bioassays were conducted over two seasons (2010 to 2011 and 2011 to 2012) using soil collected at multiple dates after imazapic application. Quantity of plant residue did not affect downy brome biomass or response to imazapic. Imazapic reduced downy brome biomass (P < 0.05) across all sampling dates in both seasons, and the response to rates was consistent up to 200 d post application. Imazapic activity over time conformed to a biphasic model with activity being consistent, or slightly improving, up to about 160 and 150 d post application, and then dropping rapidly to the final sampling event 287 and 272 d post application in rangeland and at CRP sites, respectively. These results indicate that fall imazapic applications in semiarid climates persist into the spring, thus providing control of both fall-emerging downy brome seedlings and seeds that overwinter and emerge the following spring.

El control químico de Bromus tectorum se ha enfocado en imazapic. Sin embargo, la eficacia de imazapic en climas semiáridos es impredecible, posiblemente por su variable actividad residual en el suelo. Nuestro objetivo fue caracterizar la actividad de imazapic a lo largo de 9 meses después de su aplicación en el otoño, la influencia de sitios bajo el Programa de Reservas para Conservación (CRP), el efecto de la dosis (0, 80, 160, 240 g ai ha−1) y la cantidad de residuos vegetales (ambiental, reducida). Se realizaron bioensayos de invernadero durante dos temporadas (2010 a 2011 y 2011 a 2012) usando suelo colectado en múltiples fechas después de la aplicación de imazapic. La cantidad de residuo vegetal no afectó la biomasa de B. tectorum o la respuesta a imazapic. Imazapic redujo la biomasa de B. tectorum (P < 0.05) en todas las fechas de muestreo en ambas temporadas, y la respuesta a las dosis fue consistente hasta 200 d después de la aplicación. La actividad de imazapic a lo largo del tiempo se ajustó a un modelo bifásico teniendo una actividad consistente o ligeramente mejorando, hasta cerca de 160 y 150 d después de la aplicación, y luego cayendo rápidamente en el evento final de muestreo a 287 y 272 d después de la aplicación en pastizales y en sitios CRP, respectivamente. Estos resultados indican que las aplicaciones de imazapic en el otoño en climas semiáridos persisten hasta la primavera, bridando así control de plántulas que emergen en el otoño de B. tectorum y semillas que sobreviven el invierno y emergen durante la siguiente primavera.

Copyright
Corresponding author
Corresponding author's E-mail: krista.ehlert@msu.montana.edu.
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

TM Aichele , D Penner (2005) Adsorption, desorption, and degradation of imidazolinone in soils. Weed Technol 19:154159

DA Ball , JP Yenish , T Alby III (2003) Effect of imazamox soil persistence on dryland rotational crops. Weed Technol 17:161165

BA Bradley (2009) Regional analysis of the impacts of climate change on cheatgrass invasion shows potential risk and opportunity. Glob Change Biol 15:196208

GA Bresnahan , WC Koskinen , AG Dexter , WE Lueschen (2000) Influence of soil pH—sorption interactions on imazethapyr carry-over. J Agric Food Chem 48:19291934

JC Davison , EG Smith (2007) Imazapic provides 2-year control of weedy annuals in a seeded Great Basin fuelbreak. Native Plants J 8:9195

DO Eberle , HR Gerber (1976) Comparitive studies of instrumental and bioassay methods for the analysis of herbicide residues. Arch Environ Contam Toxicol 4:101118

AC Elseroad , NT Rudd (2011) Can imazapic increase native species abundance in cheatgrass (Bromus tectorum) invaded native plant communities? Rangel Ecol Manag 64:641648

GB Kyser , JM DiTomaso , MP Doran , SB Orloff , RG Wilson , DL Lancaster , DF Lile , ML Porath (2007) Control of medusahead (Taeniatherum caput-medusae) and other annual grasses with imazapic. Weed Technol 21:6685

J Mangold , H Parkinson , C Duncan , P Rice , E Davis , F Menalled (2013) Downy brome (Bromus tectorum L.) control with imazapic on Montana rangeland. Invasive Plant Sci Manag 6:554558

C Morris , T Monaco , CW Rigby (2009) Variable impacts of imazapic rate on downy brome (Bromus tectorum) and seeded species in two rangeland communities. Invasive Plant Sci Manag 2:110119

A Onofri (1996) Biological activity, field persistence and safe recropping intervals for imazethapyr and rimsulfuron on a silty-clay soil. Weed Res 36:7383

SM Owen , CH Sieg , CA Gehring (2011) Rehabilitating downy brome (Bromus tectorum)—invaded shrublands using imazapic and seeding with native shrubs. Invasive Plant Sci Manag 4:223233

RD Ranft , SS Seefeldt , M Xhang , DL Barnes (2010) Development of a soil bioassay for triclopyr residues and comparison with a laboratory extraction. Weed Technol 24:538543

L Sheley , F Carpinelli , RL Sheley , MF Carpinelli , KJR Morghan (2007) Effects of imazapic on target and nontarget vegetation during revegetation. Weed Technol 21:10711081

JC Streibig (1988) Herbicide bioassay. Weed Res 28:479484

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Weed Technology
  • ISSN: 0890-037X
  • EISSN: 1550-2740
  • URL: /core/journals/weed-technology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords:

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 4 *
Loading metrics...

Abstract views

Total abstract views: 17 *
Loading metrics...

* Views captured on Cambridge Core between 20th January 2017 - 21st September 2017. This data will be updated every 24 hours.