The Biology of Downy Brome (Bromus tectorum)

Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 7-12 ◽  
Author(s):  
Donald C. Thill ◽  
K. George Beck ◽  
Robert H. Callihan
Keyword(s):  
United States ◽  
British Columbia ◽  
Triticum Aestivum ◽  
Bromus Tectorum ◽  
Southeastern United States ◽  
The United States ◽  
Early Spring ◽  
Western United States ◽  
Downy Brome ◽  
Perennial Grassland

Downy brome (Bromus tectorumL. # BROTE), also known as cheatgrass, downy chess, broncograss, Mormon oats, and junegrass, was introduced into the United States from Europe, apparently during the middle of the nineteenth century (11, 21). According to Mack (23), downy brome entered British Columbia, Washington, and Utah around 1890; and by 1928 it had reached its present range, occupying much of the perennial grassland in Washington, Idaho, Oregon, Nevada, Utah, and British Columbia. Today, downy brome is a widespread weed throughout most of Canada, Mexico, and the United States, except for the southeastern United States (5, 17). Some consider downy brome to be an important forage because it provides most of the early spring grazing for livestock in western United States rangeland (21). However, it is also considered a troublesome weed in rangeland (31), winter wheat (Triticum aestivumL.) (27), several other crops (29), and noncropland (32).

AIR-BORNE POLLEN SURVEYS IN BRITISH COLUMBIA

1967 ◽  
Vol 47 (3) ◽  
pp. 251-261 ◽  
Author(s):  
I. J. Bassett ◽  
C. W. Crompton
Keyword(s):  
United States ◽  
British Columbia ◽  
North America ◽  
Late Summer ◽  
The United States ◽  
Early Spring ◽  
Causative Agents ◽  
Early Fall ◽  
Trees And Shrubs

Results from 17 pollen collecting stations in British Columbia indicate that air-borne pollen of ragweeds and their relatives, the principal causative agents of hay fever in North America, is practically absent throughout the province. Coniferous trees and shrubs such as pines, spruces, firs, cedars, Douglas fir, hemlocks and junipers produce the greater part of the air-borne pollen from March to early July. Pollen from alders, poplars, willows and birches is also prevalent in some areas in the early spring. The peak periods of grass pollen near the United States–Canadian border occur mainly in June and the early part of July, while further north they are about a month later. Of the four types of plantain pollen identified from the different collecting stations, English plantain was the most common, especially in the southwesterly part of the province. Pollen from the lambs’-quarters and amaranth families and wormwoods occurs mainly in the late summer and early fall and is more abundant in the dry interior than along the coast.

Microsite Requirements for Downy Brome (Bromus tectorum) Infestation and Control on Sagebrush Rangelands

Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 13-17 ◽  
Author(s):  
Raymond A. Evans ◽  
James A. Young
Keyword(s):  
United States ◽  
Bromus Tectorum ◽  
Perennial Grasses ◽  
Western United States ◽  
Downy Brome ◽  
Forage Production ◽  
And Control

The sagebrush (Artemisia)-grass ecosystem is an extensive and important rangeland type in the western United States. Estimates of total area of this ecosystem vary from 38 million ha (21, 22) to 109 million ha (3). Of the sagebrush-grass rangelands, 88% are degraded to the point that they are producing 50% or less of their forage potential (22). Low forage production on these rangelands has been caused by overgrazing and other past land abuses (24) resulting in severe depletion of native perennial grasses, dominance of brush, and, on millions of hectares, downy brome (Bromus tectorumL. # BROTE) dominance of the understory.

The History and Distribution of Downy Brome (Bromus tectorum) in North America

Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 2-6 ◽  
Author(s):  
Larry A. Morrow ◽  
Phillip W. Stahlman
Keyword(s):  
United States ◽  
North America ◽  
Winter Wheat ◽  
Great Basin ◽  
Bromus Tectorum ◽  
Production Systems ◽  
Western United States ◽  
Downy Brome ◽  
Tillage Practices ◽  
Agricultural Production Systems

Downy brome (Bromus tectorumL. # BROTE) has developed into a severe weed in several agricultural production systems throughout North America, particularly on rangeland and in winter wheat (Triticum aestivumL.). Several million hectares of winter wheat, pastureland, alfalfa (Medicago sativaL.), grass seed fields, and overgrazed rangeland, as well as other crops, have been invaded by this annual grass since its introduction into this hemisphere. Downy brome is most abundant in the Great Basin and Columbia Basin areas of the western United States, but is found throughout the continental United States and parts of Canada and Mexico. In some cases, the vegetation on overgrazed rangeland consists totally of downy brome, while winter wheat growers in the western United States proclaim it as their worst weed problem. Changes in tillage practices that are currently being implemented for the control of soil erosion coupled with the lack of selective herbicides for the control of downy brome have aided its increase and spread.

scholarly journals Temperature and Precipitation Extremes in the United States: Quantifying the Responses to Anthropogenic Aerosols and Greenhouse Gases,+

2016 ◽  
Vol 29 (7) ◽  
pp. 2689-2701 ◽  
Author(s):  
Nora R. Mascioli ◽  
Arlene M. Fiore ◽  
Michael Previdi ◽  
Gustavo Correa
Keyword(s):  
United States ◽  
Greenhouse Gases ◽  
Greenhouse Gas ◽  
Heat Waves ◽  
Southeastern United States ◽  
The United States ◽  
Western United States ◽  
Anthropogenic Aerosols ◽  
Temperature And Precipitation ◽  
Model Aerosol

Abstract Changes in extreme temperatures, heat waves, and heavy rainfall events have adverse effects on human health, air quality, and water resources. With aerosol-only (AER) and greenhouse gas–only (GHG) simulations from 1860 to 2005 in the GFDL CM3 chemistry–climate model, aerosol-induced versus greenhouse gas–induced changes in temperature (summer) and precipitation (all seasons) extremes over the United States are investigated. Small changes in these extremes in the all forcing simulations reflect cancellations between the effects of increasing anthropogenic aerosols and greenhouse gases. In AER, extreme high temperatures and the number of days with temperatures above the 90th percentile decline over most of the United States. The strongest response occurs in the western United States (−2.0°C and −14 days, regionally averaged) and the weakest response occurs in the southeastern United States (−0.6°C and −4.8 days). An opposite-signed response pattern occurs in GHG (+2.3°C and +11.5 days over the western United States and +1.6°C and +7.2 days over the southeastern United States). The similar spatial response patterns in AER versus GHG suggest a preferred regional mode of response that is largely independent of the type of forcing. Extreme precipitation over the eastern United States decreases in AER, particularly in winter, and increases over the eastern and central United States in GHG, particularly in spring. Over the twenty-first century under the representative concentration pathway 8.5 (RCP8.5) emissions scenario, the patterns of extreme temperature and precipitation associated with greenhouse gas forcing dominate.

Sulfonylurea Herbicides Suppress Downy Brome (Bromus tectorum) in Winter Wheat (Triticum aestivum)

1994 ◽  
Vol 8 (4) ◽  
pp. 812-818 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Mosad Abd El-Hamid
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Wheat Yield ◽  
Early Spring ◽  
Sulfonylurea Herbicides ◽  
Downy Brome ◽  
West Central ◽  
Late Fall ◽  
Better Than

In separate studies in west-central Kansas, a prepackaged mixture of chlorsulfuron + metsulfuron (5:1 w/w) and triasulfuron alone or in combination with metribuzin as a sequential or tank mix treatment were evaluated two years for downy brome control in winter wheat. Downy brome and wheat responses to each herbicide alone PRE or plus metribuzin POST varied between years. Visually, downy brome biomass was reduced 32 to 79% by chlorsulfuron + metsulfuron at 16 to 26 g ai/ha and 58 to 76% by triasulfuron at 30 g ai/ha applied PRE. Metribuzin POST at 158 g ai/ha following chlorsulfuron + metsulfuron PRE at 26 g/ha and metribuzin POST at 140 g/ha or more following triasulfuron PRE at 30 g/ha reduced downy brome biomass in both years more than PRE treatments alone. Chlorsulfuron + metsulfuron at 11 or 16 g/ha plus metribuzin at 105 or 158 g/ha applied POST affected downy brome less in 1992 than chlorsulfuron + metsulfuron applied PRE at 21 or 26 g/ha. Conversely in 1993, POST treatments except for chlorsulfuron + metsulfuron at 11 or 16 g/ha plus metribuzin at 105 g/ha affected downy brome more than PRE treatments. Triasulfuron plus metribuzin POST in late fall controlled downy brome better than a sequential application in one of two years; late-fall POST was better than early-spring POST applications in both years. Despite some treatments retarding growth, no treatment in either study reduced wheat yield in 1992. However in 1993, chlorsulfuron + metsulfuron PRE at 26 g/ha, chlorsulfuron + metsulfuron at 16 g/ha plus metribuzin at 105 or 158 g/ha applied POST, and metribuzin POST at 315 g/ha reduced wheat yields. Triasulfuron at 30 g/ha plus metribuzin at 140 g/ha or higher applied PRE, sequentially, or POST in late fall and metribuzin applied POST in early spring at 280 g/ha also reduced wheat yields.

Downy Brome (Bromus tectorum) Density and Relative Time of Emergence Affects Interference in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 551-556 ◽  
Author(s):  
Robert E. Blackshaw
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Seed Yield ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Wheat Yield ◽  
Growing Season ◽  
Early Spring ◽  
Downy Brome ◽  
Relative Time

Field experiments over 3 yr at Lethbridge, Alberta, determined the effect of various downy brome densities and times of its emergence on winter wheat biomass and seed yield. Downy brome reduced wheat biomass up to 59% and seed yield up to 68%. Time of downy brome emergence relative to wheat affected the magnitude of these yield reductions more than the density of downy brome. At comparable densities, downy brome caused 2- to 5-fold greater reductions in yield when it emerged within 3 wk after winter wheat than when it emerged 6 wk after wheat or in early spring. Late-emerging downy brome caused significant wheat yield or biomass losses only at densities of 200 to 400 plants m-2. Late-emerging downy brome plants were strongly shaded (70 to 90%) by winter wheat throughout much of the growing season.

Writing Time in Metaphors

2018 ◽  
Author(s):  
Jennifer J. Smith
Keyword(s):  
United States ◽  
The United States ◽  
Western United States ◽  
Entire System ◽  
Language And Culture ◽  
Space Race ◽  
Do So

Coherence of place often exists alongside irregularities in time in cycles, and chapter three turns to cycles linked by temporal markers. Ray Bradbury’s The Martian Chronicles (1950) follows a linear chronology and describes the exploration, conquest, and repopulation of Mars by humans. Conversely, Louise Erdrich’s Love Medicine (1984) jumps back and forth across time to narrate the lives of interconnected families in the western United States. Bradbury’s cycle invokes a confluence of historical forces—time as value-laden, work as a calling, and travel as necessitating standardized time—and contextualizes them in relation to anxieties about the space race. Erdrich’s cycle invokes broader, oppositional conceptions of time—as recursive and arbitrary and as causal and meaningful—to depict time as implicated in an entire system of measurement that made possible the destruction and exploitation of the Chippewa people. Both volumes understand the United States to be preoccupied with imperialist impulses. Even as they critique such projects, they also point to the tenacity with which individuals encounter these systems, and they do so by creating “interstitial temporalities,” which allow them to navigate time at the crossroads of language and culture.

Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy

Science ◽  
2021 ◽  
Vol 371 (6536) ◽  
pp. eaax9050
Author(s):  
Steffen Breinlinger ◽  
Tabitha J. Phillips ◽  
Brigette N. Haram ◽  
Jan Mareš ◽  
José A. Martínez Yerena ◽  
...  
Keyword(s):  
United States ◽  
Aquatic Vegetation ◽  
Southeastern United States ◽  
Hydrilla Verticillata ◽  
Toxin Production ◽  
The United States ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Bald Eagles ◽  
Cyanobacterial Species

Vacuolar myelinopathy is a fatal neurological disease that was initially discovered during a mysterious mass mortality of bald eagles in Arkansas in the United States. The cause of this wildlife disease has eluded scientists for decades while its occurrence has continued to spread throughout freshwater reservoirs in the southeastern United States. Recent studies have demonstrated that vacuolar myelinopathy is induced by consumption of the epiphytic cyanobacterial species Aetokthonos hydrillicola growing on aquatic vegetation, primarily the invasive Hydrilla verticillata. Here, we describe the identification, biosynthetic gene cluster, and biological activity of aetokthonotoxin, a pentabrominated biindole alkaloid that is produced by the cyanobacterium A. hydrillicola. We identify this cyanobacterial neurotoxin as the causal agent of vacuolar myelinopathy and discuss environmental factors—especially bromide availability—that promote toxin production.

scholarly journals Patterns of dental antibiotic prescribing in 2017: Australia, England, United States, and British Columbia (Canada)

2021 ◽  
pp. 1-8
Author(s):  
Wendy Thompson ◽  
Leanne Teoh ◽  
Colin C. Hubbard ◽  
Fawziah Marra ◽  
David M. Patrick ◽  
...  
Keyword(s):  
United States ◽  
British Columbia ◽  
Broad Spectrum ◽  
Antibiotic Prescription ◽  
Population Level ◽  
The United States ◽  
Antibiotic Prescribing ◽  
Prescribing Behavior ◽  
The Us ◽  
Amoxicillin Clavulanic Acid

Abstract Objective: Our objective was to compare patterns of dental antibiotic prescribing in Australia, England, and North America (United States and British Columbia, Canada). Design: Population-level analysis of antibiotic prescription. Setting: Outpatient prescribing by dentists in 2017. Participants: Patients receiving an antibiotic dispensed by an outpatient pharmacy. Methods: Prescription-based rates adjusted by population were compared overall and by antibiotic class. Contingency tables assessed differences in the proportion of antibiotic class by country. Results: In 2017, dentists in the United States had the highest antibiotic prescribing rate per 1,000 population and Australia had the lowest rate. The penicillin class, particularly amoxicillin, was the most frequently prescribed for all countries. The second most common agents prescribed were clindamycin in the United States and British Columbia (Canada) and metronidazole in Australia and England. Broad-spectrum agents, amoxicillin-clavulanic acid, and azithromycin were the highest in Australia and the United States, respectively. Conclusion: Extreme differences exist in antibiotics prescribed by dentists in Australia, England, the United States, and British Columbia. The United States had twice the antibiotic prescription rate of Australia and the most frequently prescribed antibiotic in the US was clindamycin. Significant opportunities exist for the global dental community to update their prescribing behavior relating to second-line agents for penicillin allergic patients and to contribute to international efforts addressing antibiotic resistance. Patient safety improvements will result from optimizing dental antibiotic prescribing, especially for antibiotics associated with resistance (broad-spectrum agents) or C. difficile (clindamycin). Dental antibiotic stewardship programs are urgently needed worldwide.

scholarly journals Dermacentor variabilis is the Predominant Dermacentor spp. (Acari: Ixodidae) Feeding on Dogs and Cats Throughout the United States

2021 ◽  
Author(s):  
Kathryn T Duncan ◽  
Meriam N Saleh ◽  
Kellee D Sundstrom ◽  
Susan E Little
Keyword(s):  
United States ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
The United States ◽  
Dermacentor Variabilis ◽  
Western United States ◽  
Its2 Region ◽  
Rrna Gene ◽  
Rocky Mountain Spotted Fever ◽  
Dermacentor Albipictus

Abstract Throughout North America, Dermacentor spp. ticks are often found feeding on animals and humans, and are known to transmit pathogens, including the Rocky Mountain spotted fever agent. To better define the identity and distribution of Dermacentor spp. removed from dogs and cats in the United States, ticks submitted from 1,457 dogs (n = 2,924 ticks) and 137 cats (n = 209 ticks) from veterinary practices in 44/50 states from February 2018-January 2020 were identified morphologically (n = 3,133); the identity of ticks from regions where Dermacentor andersoni (Stiles) have been reported, and a subset of ticks from other regions, were confirmed molecularly through amplification and sequencing of the ITS2 region and a 16S rRNA gene fragment. Of the ticks submitted, 99.3% (3,112/3,133) were Dermacentor variabilis (Say), 0.4% (12/3,133) were D. andersoni, and 0.3% (9/3,133) were Dermacentor albipictus (Packard). While translocation of pets prior to tick removal cannot be discounted, the majority (106/122; 87%) of Dermacentor spp. ticks removed from dogs and cats in six Rocky Mountain states (Montana, Idaho, Wyoming, Nevada, Utah, and Colorado) were D. variabilis, suggesting this species may be more widespread in the western United States than is currently recognized, or that D. andersoni, if still common in the region, preferentially feeds on hosts other than dogs and cats. Together, these data support the interpretation that D. variabilis is the predominant Dermacentor species found on pets throughout the United States, a finding that may reflect recent shifts in tick distribution.

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