Variable Impacts of Imazapic Rate on Downy Brome (<i>Bromus tectorum</i>) and Seeded Species in Two Rangeland Communities

Morris, Christo; Monaco, Thomas A.; Rigby, Craig W.

doi:10.1614/ipsm-08-104.1

Cited by 63 publications

(89 citation statements)

References 65 publications

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“…Our results suggest herbicides with residual soil activity provided no more than two seasons of control when they were not part of an integrated management plan and this duration of control is similar to previous reports (Morris et al 2009;Kyser et al 2013). …”

Section: Integrating Prescribed Burning With Herbicidessupporting

confidence: 90%

“…In 2012, litter amount was high in the non-burned study area, but less than 66% of litter remained in 2013 due to lack of precipitation the previous season. Fluctuations in litter and downy brome biomass due to precipitation have been reported previously and serve as reminder why generalizing about treatment impacts is so difficult (Uresk et al 1979;Morris et al 2009;Bansal et al 2014). In September 2013, the Front Range of Colorado experienced some extreme weather that NOAA classified as a 1,000-year rainfall event.…”

Section: Herbicide Sorption To Littermentioning

confidence: 62%

“…Integrating burning with herbicides can provide longer and more consistent downy brome control; however, there is still much debate around which herbicide rates and timings are most efficacious (Kyser et al 2007;Morris et al 2009). speculated that abiotic factors such a precipitation were responsible for much of the variability in the success of imazapic treatments.…”

Section: Herbicide Sorption To Littermentioning

confidence: 99%

“…Due to foliar and residual soil activity, imazapic and tebuthiuron can control downy brome for at least two seasons. Imazapic has provided variable control, ranging from one to three seasons, and to our knowledge, only one study has reported control of downy brome by tebuthiuron (Davison and Smith 2007;Kyser et al 2007;Duncan et al 2009;Morris et al 2009;Elseroad and Rudd 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Glyphosate, imazapic, and tebuthiuron have all shown efficacy in controlling downy brome, but the length of control that they provide is variable (Morrow et al 1977;Beck et al 1995;Whitson and Koch 1998;Blumenthal et al 2006;Davison and Smith 2007;Morris et al 2009;Elseroad and Rudd 2011;). Long-term control by glyphosate is unlikely due to a lack of residual soil activity; however, it's been reported to reduce downy brome during the season of application (Morrow et al 1977;Beck et al 1995;Whitson and Koch 1998).…”

Section: Introductionmentioning

confidence: 99%

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Litter Reduction by Prescribed Burning Can Extend Downy Brome Control

Kessler

Nissen

Meiman

et al. 2015

Rangeland Ecology & Management

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LITTER REDUCTION BY PRESCRIBED BURNINGCAN EXTEND DOWNY BROME CONTROL Downy brome (Bromus tectorum L.) is a highly successful invasive species primarily because it fills an open niche in native plant communities. It also produces large amounts of litter over time. We hypothesized that removing accumulated litter with a prescribed burn before applying herbicides would improve herbicide efficacy, extending the duration of control. In January 2012, two downy brome infested sites were burned. In March 2012, post-emergent applications of glyphosate, imazapic, and tebuthiuron were made in a split-plot design.Aboveground biomass was collected at 6, 18 and 27 months after treatment (MAT) to evaluate treatment effects. In non-burned areas, all herbicide treatments were similar to the control 27 MAT; however, burning combined with imazapic or tebuthiuron reduced downy brome biomass 27 MAT by 81% ± 4.6 SE and 84% ± 19.3 SE, respectively. Remnant species responded positively to burning and herbicide treatments. Native cool season grass biomass increased after burning while native warm season grass biomass increased following tebuthiuron treatments.The impact of litter on imazapic and tebuthiuron availability was also evaluated. Herbicide interception increased in a linear relationship with increasing litter. For every 50 g·m -2 increase in litter there was a 7% increase in the amount of herbicide intercepted, meaning that 75% of the applied herbicide was intercepted by 360 g·m -2 of litter. A simulated rainfall event of 5 mm, 7 days after application, removed a significant amount of herbicide. This indicates that at sites with surface litter, timely precipitation could be critical for herbicide efficacy; however, when burning was used to remove litter and was followed by herbicides with residual soil activity, iii downy brome control was extended. Due to downy brome's relatively short seed viability in the soil, extending herbicide efficacy to several years could help to reduce the soil seed bank.iv ACKNOWLEDGEMENTS

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Section: Integrating Prescribed Burning With Herbicidessupporting

confidence: 90%

Section: Herbicide Sorption To Littermentioning

confidence: 62%

Section: Herbicide Sorption To Littermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Litter Reduction by Prescribed Burning Can Extend Downy Brome Control

Kessler

Nissen

Meiman

et al. 2015

Rangeland Ecology & Management

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Herbicide effects on the establishment of a native bunchgrass in annual grass invaded areas: Indaziflam versus imazapic

Terry

Madsen

Gill

et al. 2021

Ecol Sol and Evidence

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1. Annual grass invasion is transforming the western United States and driving a need for restoration techniques that can both reduce exotic annual grass abundance and allow revegetation of native species. Pre-emergent herbicides can provide control of annual grasses, but when applied concurrently with direct seeding efforts, the herbicide can also impact seeded species. Indaziflam is a relatively new herbicide that may provide extended control of exotic annual grasses, but little is known about its effects when applied at the time of seeding. 2. In this study, we compared indaziflam to imazapic, a popular herbicide used in restoration efforts, to understand how indaziflam affects plant establishment of a native species, bluebunch wheatgrass Pseudoroegneria spicata (Pursh) Á. Löve. We created furrows on half our treatments to limit herbicide concentrations and potentially create a safe-site for seeding bluebunch wheatgrass. 3. During the 2-year study, indaziflam provided consistent control of the annual weed, downy brome Bromus tectorum L., whereas imazapic control decreased sharply with time. Indaziflam and imazapic decreased bluebunch wheatgrass seedling emergence by 96% and 46%, and 2-year plant density by 91% and 65%, respectively, compared to non-herbicide treatments. Both herbicides reduced aboveground biomass of bluebunch wheatgrass by over 85% 2 years after seeding/herbicide application. 4. Furrow treatments mitigated imazapic's effect on bluebunch wheatgrass, but did not limit the impacts by indaziflam. 5. Herbicide can be used in conjunction with direct seeding efforts, but mitigation of the effects to native seeds will depend on herbicide specifics such as mode of action and soil mobility.

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Intra‐site sources of restoration variability in severely invaded rangeland: Strong temporal effects of herbicide–weather interactions; weak spatial effects of plant community patch type and litter

Donaldson

Germino

2022

Ecol Sol and Evidence

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Invasions by exotic annual grasses (EAGs) are replacing native perennials in semiarid areas globally, including the vast sagebrush‐steppe rangelands of western North America. Efforts to eradicate EAGs and restore perennials have had mixed success, especially in relatively warm and dry areas where EAGs had high dominance prior to intervention. Greater consideration of the ecological sources of variability in EAG treatment outcomes may improve success. We hypothesized that herbicide and restoration outcomes would be influenced by restoration strategy (type of herbicide, seeding or planting, timing of treatment) and underlying spatial variability associated with plant community patch type and litter, all applied in a landscape‐scale experiment in a severely invaded area in Southern Idaho, USA. EAGs, specifically medusahead (Taeniatherum caput‐medusae [L.] Nevski), were strongly reduced for up to 3 years (maximum observation period) by the pre‐emergent herbicide indaziflam, whereas the pre/post‐emergent imazapic reduced EAGs only when applied twice. Indaziflam effects were greater when post‐spray moisture was greater, and also when co‐applied with imazapic, but reapplying indaziflam did not lead to additional reduction of EAGs. Imazapic and indaziflam each stimulated species‐specific, secondary invasion by exotic and/or invasive tall forbs. Application of the broadleaf herbicide aminopyralid provided only a fleeting 1 year of control of a dominant, highly noxious forb skeletonweed (Chondrilla juncea L.). Underlying heterogeneity in plant community patch type (dominant herb species) explained only ∼5% of variation in the herbicide effects, and manipulation of litter prior to spraying had no effect. Several years of seedings and planting resulted in no establishment of native perennials. Herbicides, especially indaziflam, appear to be an effective tool for reducing EAGs for multiple years in the challenging restoration conditions we evaluated, particularly if their application coincides with suitable moisture. However, restoring the perennials required for longer term resistance to reinvasion is a serious challenge that could be avoided with preservation of perennials.

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Variable Impacts of Imazapic Rate on Downy Brome (Bromus tectorum) and Seeded Species in Two Rangeland Communities

Cited by 63 publications

References 65 publications

Litter Reduction by Prescribed Burning Can Extend Downy Brome Control

Litter Reduction by Prescribed Burning Can Extend Downy Brome Control

Herbicide effects on the establishment of a native bunchgrass in annual grass invaded areas: Indaziflam versus imazapic

Intra‐site sources of restoration variability in severely invaded rangeland: Strong temporal effects of herbicide–weather interactions; weak spatial effects of plant community patch type and litter

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