Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Bromus tectorum
(downy brome)

Toolbox

Datasheet

Bromus tectorum (downy brome)

Summary

  • Last modified
  • 18 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Bromus tectorum
  • Preferred Common Name
  • downy brome
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
  • Summary of Invasiveness
  • B. tectorum has tremendous phenotypic plasticity, with self fertilization permitting continuous replication of successful genotypes, and occasional out-crossing inducing genotypic variability and adaptation to new environments. Seeds have the advanta...

Don't need the entire report?

Generate a print friendly version containing only the sections you need.

Generate report

Pictures

Top of page
PictureTitleCaptionCopyright
Bromus tectorum (downy brome, cheatgrass); habit. Sliding Sands Haleakala National Park, Maui, Hawaii, USA. October 2007.
TitleHabit
CaptionBromus tectorum (downy brome, cheatgrass); habit. Sliding Sands Haleakala National Park, Maui, Hawaii, USA. October 2007.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Bromus tectorum (downy brome, cheatgrass); habit. Sliding Sands Haleakala National Park, Maui, Hawaii, USA. October 2007.
HabitBromus tectorum (downy brome, cheatgrass); habit. Sliding Sands Haleakala National Park, Maui, Hawaii, USA. October 2007.©Forest Starr & Kim Starr - CC BY 4.0
Nodding panicle of B. tectorum.
TitlePanicle
CaptionNodding panicle of B. tectorum.
Copyright©James A. Young
Nodding panicle of B. tectorum.
PanicleNodding panicle of B. tectorum.©James A. Young
Spikelets of B. tectorum.
TitleSpikelets
CaptionSpikelets of B. tectorum.
Copyright©James A. Young
Spikelets of B. tectorum.
SpikeletsSpikelets of B. tectorum.©James A. Young
Panicle of B. tectorum during the red colour stage that occurs just before maturity.
TitleMaturing panicle
CaptionPanicle of B. tectorum during the red colour stage that occurs just before maturity.
Copyright©James A. Young
Panicle of B. tectorum during the red colour stage that occurs just before maturity.
Maturing paniclePanicle of B. tectorum during the red colour stage that occurs just before maturity.©James A. Young
Caryopses of B. tectorum.
TitleCaryopses
CaptionCaryopses of B. tectorum.
Copyright©James A. Young
Caryopses of B. tectorum.
CaryopsesCaryopses of B. tectorum.©James A. Young
Semi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understorey of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.
TitleSemi-arid rangeland
CaptionSemi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understorey of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.
Copyright©James A. Young
Semi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understorey of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.
Semi-arid rangelandSemi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understorey of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.©James A. Young
B. tectorum infestations are most common in areas where human environmental disturbance is greatest. In the Intermountain Area of the western USA, the suburban interface with rangelands brings the invasive annual grass in contact with homes. This means extreme danger from wildfires. Cheatgrass has the highest name recognition with the general public of any exotic weed in the Intermountain Area.
TitleInvasive habit
CaptionB. tectorum infestations are most common in areas where human environmental disturbance is greatest. In the Intermountain Area of the western USA, the suburban interface with rangelands brings the invasive annual grass in contact with homes. This means extreme danger from wildfires. Cheatgrass has the highest name recognition with the general public of any exotic weed in the Intermountain Area.
Copyright©James A. Young
B. tectorum infestations are most common in areas where human environmental disturbance is greatest. In the Intermountain Area of the western USA, the suburban interface with rangelands brings the invasive annual grass in contact with homes. This means extreme danger from wildfires. Cheatgrass has the highest name recognition with the general public of any exotic weed in the Intermountain Area.
Invasive habitB. tectorum infestations are most common in areas where human environmental disturbance is greatest. In the Intermountain Area of the western USA, the suburban interface with rangelands brings the invasive annual grass in contact with homes. This means extreme danger from wildfires. Cheatgrass has the highest name recognition with the general public of any exotic weed in the Intermountain Area.©James A. Young
If the native perennial grasses are depleted by excessive grazing, B. tectorum will gain dominance of the understorey and the site will burn in a wildfire. After a fire the woody species will be gone and the exotic annual will have complete dominance. The site will be closed to recruitment of seedlings of native perennial species.
TitleWildfire site
CaptionIf the native perennial grasses are depleted by excessive grazing, B. tectorum will gain dominance of the understorey and the site will burn in a wildfire. After a fire the woody species will be gone and the exotic annual will have complete dominance. The site will be closed to recruitment of seedlings of native perennial species.
Copyright©James A. Young
If the native perennial grasses are depleted by excessive grazing, B. tectorum will gain dominance of the understorey and the site will burn in a wildfire. After a fire the woody species will be gone and the exotic annual will have complete dominance. The site will be closed to recruitment of seedlings of native perennial species.
Wildfire siteIf the native perennial grasses are depleted by excessive grazing, B. tectorum will gain dominance of the understorey and the site will burn in a wildfire. After a fire the woody species will be gone and the exotic annual will have complete dominance. The site will be closed to recruitment of seedlings of native perennial species.©James A. Young
Control treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation has produced a dense stand of B. tectorum. B. tectorum has been suppressed by immobilizing nitrogen by adding sucrose to the soil. The grass seedlings visible on the treated area are the native perennial Achnatherum hymenoides, which came spontaneously from the seedbank. There were no native perennial grass seedlings in the control plots. Note spade is 1 m tall.
TitleControl treatment
CaptionControl treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation has produced a dense stand of B. tectorum. B. tectorum has been suppressed by immobilizing nitrogen by adding sucrose to the soil. The grass seedlings visible on the treated area are the native perennial Achnatherum hymenoides, which came spontaneously from the seedbank. There were no native perennial grass seedlings in the control plots. Note spade is 1 m tall.
Copyright©James A. Young
Control treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation has produced a dense stand of B. tectorum. B. tectorum has been suppressed by immobilizing nitrogen by adding sucrose to the soil. The grass seedlings visible on the treated area are the native perennial Achnatherum hymenoides, which came spontaneously from the seedbank. There were no native perennial grass seedlings in the control plots. Note spade is 1 m tall.
Control treatmentControl treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation has produced a dense stand of B. tectorum. B. tectorum has been suppressed by immobilizing nitrogen by adding sucrose to the soil. The grass seedlings visible on the treated area are the native perennial Achnatherum hymenoides, which came spontaneously from the seedbank. There were no native perennial grass seedlings in the control plots. Note spade is 1 m tall.©James A. Young
The cycle of B. tectorum invasion and wildfires on rangelands can be broken through weed control and artificially seeding perennial grasses.
TitleArtificially seeded perennial grasses
CaptionThe cycle of B. tectorum invasion and wildfires on rangelands can be broken through weed control and artificially seeding perennial grasses.
Copyright©James A. Young
The cycle of B. tectorum invasion and wildfires on rangelands can be broken through weed control and artificially seeding perennial grasses.
Artificially seeded perennial grassesThe cycle of B. tectorum invasion and wildfires on rangelands can be broken through weed control and artificially seeding perennial grasses.©James A. Young
Control treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation produced the dense stand of B. tectorum. Note spade is 1 m high.
TitleControl treatment
CaptionControl treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation produced the dense stand of B. tectorum. Note spade is 1 m high.
Copyright©James A. Young
Control treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation produced the dense stand of B. tectorum. Note spade is 1 m high.
Control treatmentControl treatment in a nitrogen immobilization experiment in the salt deserts of the Intermountain Area of western North America. The site is in the 100 mm precipitation zone, but above average precipitation produced the dense stand of B. tectorum. Note spade is 1 m high.©James A. Young
When a B. tectorum dominated site burns, the soil surface is exposed to accelerated erosion. A high intensive summer thunder storm hit the slope after a wildfire causing the erosion. Unburned B. tectorum in the valley bottom.
TitleWildfire site
CaptionWhen a B. tectorum dominated site burns, the soil surface is exposed to accelerated erosion. A high intensive summer thunder storm hit the slope after a wildfire causing the erosion. Unburned B. tectorum in the valley bottom.
Copyright©James A. Young
When a B. tectorum dominated site burns, the soil surface is exposed to accelerated erosion. A high intensive summer thunder storm hit the slope after a wildfire causing the erosion. Unburned B. tectorum in the valley bottom.
Wildfire siteWhen a B. tectorum dominated site burns, the soil surface is exposed to accelerated erosion. A high intensive summer thunder storm hit the slope after a wildfire causing the erosion. Unburned B. tectorum in the valley bottom.©James A. Young
Semi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understory of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.
TitleSemi-arid rangeland
CaptionSemi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understory of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.
Copyright©James A. Young
Semi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understory of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.
Semi-arid rangelandSemi-arid rangeland in the Intermountain Area of the western USA in excellent ecological condition. Juniperus occidentalis woodland with Artemisia tridentata shrub layer and an understory of the perennial grass Pseudoroegneria spicata. The site has been invaded by B. tectorum, but the abundance of native herbaceous perennials suppresses the exotic annual.©James A. Young
Looking directly down on a dense stand of B. tectorum.
TitleHabit
CaptionLooking directly down on a dense stand of B. tectorum.
Copyright©James A. Young
Looking directly down on a dense stand of B. tectorum.
HabitLooking directly down on a dense stand of B. tectorum.©James A. Young

Identity

Top of page

Preferred Scientific Name

  • Bromus tectorum L.

Preferred Common Name

  • downy brome

Other Scientific Names

  • Anisantha tectorum (L.) Nevski

International Common Names

  • English: bronco grass; cheat grass; cheatgrass; drooping brome grass; nodding brome grass; six weeks grass
  • Spanish: bromo velloso; espiguilla colgante
  • French: brome des toits

Local Common Names

  • Canada: nodding brome
  • Germany: Dach- Trespe
  • Italy: forasacco dei tetti
  • Japan: umanochahiki
  • Netherlands: muurdravik; zwenkdravik
  • Sweden: taklosta

EPPO code

  • BROTE (Bromus tectorum)

Summary of Invasiveness

Top of page B. tectorum has tremendous phenotypic plasticity, with self fertilization permitting continuous replication of successful genotypes, and occasional out-crossing inducing genotypic variability and adaptation to new environments. Seeds have the advantage of simultaneous germination and through dormancy acquired in the seedbed, continuous germination and the development of large, persistent seedbanks. B. tectorum has an excellent long-distance seed dispersal mechanism through contamination of seed lots of crop species and through wool, hair, clothing, and vehicle contamination. B. tectorum is a highly invasive exotic weed that truncates succession to remain a dominant species for prolonged periods of time. B. tectorum is one of the few invasive annual exotic species that is a major weed of rangelands and agronomic fields in North America.

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Poaceae
  •                             Genus: Bromus
  •                                 Species: Bromus tectorum

Notes on Taxonomy and Nomenclature

Top of page In Russia, Anisantha tectorum (L.) Nevski is used by some authors as the taxon for this species, but Bromus tectorum L. is universally used in publications in English (Kostivkovsky and Young, 2000). If near universal agreement is found on the scientific name, chaos prevails on common names. The Weed Science Society of America has assigned the common name of downy brome for B. tectorum. In the western USA it is widely known as cheatgrass. Other common names in the USA include bronco grass, six weeks grass and military grass. In western Canada it is known as nodding brome (Taylor and MacBryde, 1977). The Latin root for the specific name tectorum refers to the roof in apparent reference to B. tectorum growing on thatched roofs (Kostivkovsky and Young, 2000).

Description

Top of page B. tectorum plants have a soft hispid pubescence throughout the leaves and stems. The leaf blades are flat and rather narrow, 2-3.5 mm broad. The stature of the plant and the number of tillers is highly variable. Plant height ranges from 2.5 to 50 cm. In dense stands, 8500 to 11,000 plants per m², B. tectorum may produce a single stem and a single diminutive panicle. In very sparse stands (10 per m²), as would occur the season after a wildfire, B. tectorum plants may reach 0.5 m in height and have a multitude of robust panicles of florets (Young et al., 1987). The panicle ranges from 6 to 20 cm in length and usually, but not always, nodding (Wilken and Painter, 2003). The spikelets are sub-cylindrical to slightly compressed. Glumes generally glabrous, but for all the inflorescence components, the presence and amount is highly variable. The upper glume is 7-12 mm long with three veins. The lower glume is 5-6 mm long with one vein. The florets are 3-7 mm long, the lemma body 9-13 mm long with 5-7 veins and the tip has two teeth 2-3 mm long. The caryopsis is about 2 cm long with a recurved, sharp-tipped awn. The colour of the caryopsis ranges from light straw to reddish brown, and is covered with silicon barbs that aid in attachment to wool, hair and clothing. The awn moves with wetting and drying forcing the sharp point of the caryopses deeper into wool or hair and even into the flesh, eyes, ears or toes of animals. B. tectorum rosettes often have bright red leaves during mid-winter, which apparently is due to nitrogen stress.

Plant Type

Top of page Annual
Grass / sedge
Herbaceous
Seed propagated

Distribution

Top of page B. tectorum is widely distributed in central Asia (Kostivkovsky and Young, 2000), with the western edge of its native range generally given as the Balkans, Europe. The present distribution of B. tectorum in Europe extends to south-western Spain, but west of the Balkans, B. tectorum is considered to be an adventive species. B. tectorum is common in the Middle East and occurs across North Africa in areas with a Mediterranean-type climate but may be considered adventive west of Egypt (Meusel et al., 1965). To the east, the native range extends into China, probably restricted to Xinjiang province. Presence in India (USDA-ARS, 2003) is probably restricted to the north. This species has been so closely associated with winter cereal grain production and range livestock grazing for such an extended period of time, it is difficult to separate native habitat from where it has been introduced in pre-history.

Distribution Table

Top of page

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

AfghanistanWidespreadNative Not invasive Kostivkovsky and Young, 2000
ArmeniaPresentNativeUSDA-ARS, 2003
AzerbaijanWidespreadNative Not invasive Kostivkovsky and Young, 2000
ChinaRestricted distributionNative Not invasive USDA-ARS, 2003
Georgia (Republic of)PresentNative Not invasive Kostivkovsky and Young, 2000
IndiaRestricted distributionNativeUSDA-ARS, 2003
IranPresentNative Not invasive Kostivkovsky and Young, 2000
IraqPresentNative Not invasive Kostivkovsky and Young, 2000
IsraelPresentNative Not invasive Kostivkovsky and Young, 2000
JordanPresentNative Not invasive Kostivkovsky and Young, 2000
KazakhstanPresentNative Not invasive Kostivkovsky and Young, 2000
KuwaitPresentNative Not invasive Kostivkovsky and Young, 2000
KyrgyzstanPresentNative Not invasive Kostivkovsky and Young, 2000
LebanonPresentNative Not invasive Kostivkovsky and Young, 2000
PakistanPresentNative Not invasive Kostivkovsky and Young, 2000
Saudi ArabiaPresentNative Not invasive Kostivkovsky and Young, 2000
SyriaPresentNative Not invasive Kostivkovsky and Young, 2000
TajikistanPresentNative Not invasive Kostivkovsky and Young, 2000
TurkeyPresentNative Not invasive Tutin et al., 1980; Kostivkovsky and Young, 2000
TurkmenistanPresentNative Not invasive Kostivkovsky and Young, 2000
United Arab EmiratesPresentNative Not invasive Kostivkovsky and Young, 2000
UzbekistanPresentNative Not invasive Kostivkovsky and Young, 2000

Africa

AlgeriaPresent Not invasive Meusel et al., 1965
EgyptPresentNative Not invasive Meusel et al., 1965
LibyaPresentIntroduced Not invasive Meusel et al., 1965
MoroccoPresentIntroduced Not invasive Meusel et al., 1965
South AfricaPresentIntroducedUSDA-ARS, 2003
Spain
-Canary IslandsPresentIntroducedUSDA-ARS, 2003
TunisiaPresentUSDA-ARS, 2003

North America

CanadaPresentPresent based on regional distribution.
-AlbertaPresentIntroduced Invasive Cronquist et al., 1977
-British ColumbiaWidespreadIntroduced Invasive Cronquist et al., 1977
-ManitobaPresentIntroduced Invasive Cronquist et al., 1977
-SaskatchewanPresentIntroduced Invasive Cronquist et al., 1977
MexicoPresentIntroduced Invasive Wiggins, 1980
USAPresentPresent based on regional distribution.
-AlabamaPresentIntroduced Not invasive Hitchcock, 1950
-AlaskaPresentIntroduced Not invasive Cronquist et al., 1977
-ArizonaWidespreadIntroduced Invasive Hitchcock, 1950
-ArkansasPresentIntroduced Invasive Hitchcock, 1950
-CaliforniaWidespreadIntroduced Invasive Hitchcock, 1950
-ColoradoWidespreadIntroduced1895 Invasive Hitchcock, 1950
-ConnecticutPresentIntroduced Not invasive Hitchcock, 1950
-DelawarePresentIntroduced Not invasive Hitchcock, 1950
-FloridaPresentIntroduced Not invasive Cronquist, 1977
-GeorgiaPresentIntroduced Not invasive Hitchcock, 1950
-HawaiiPresentIntroducedUSDA-NRCS, 2002
-IdahoWidespreadIntroduced Invasive Hitchcock, 1950
-IllinoisPresentIntroduced Not invasive Hitchcock, 1950
-IndianaPresentIntroduced Not invasive Hitchcock, 1950
-IowaPresentIntroduced Not invasive Hitchcock, 1950
-KansasWidespreadIntroduced Invasive Hitchcock, 1950
-KentuckyPresentIntroduced Not invasive Hitchcock, 1950
-LouisianaPresentIntroduced Not invasive Hitchcock, 1950
-MainePresentIntroduced Not invasive Hitchcock, 1950
-MarylandPresentIntroduced Not invasive Hitchcock, 1950
-MassachusettsPresentIntroduced Not invasive Hitchcock, 1950
-MichiganPresentIntroduced Not invasive Hitchcock, 1950
-MinnesotaPresentIntroduced Not invasive Hitchcock, 1950
-MississippiPresentIntroduced Not invasive Hitchcock, 1950
-MissouriPresentIntroduced Not invasive Hitchcock, 1950
-MontanaWidespreadIntroduced Invasive Hitchcock, 1950
-NebraskaWidespreadIntroduced Invasive Hitchcock, 1950
-NevadaWidespreadIntroduced Invasive Hitchcock, 1950
-New HampshirePresentIntroduced Not invasive Hitchcock, 1950
-New JerseyPresentIntroduced Not invasive Hitchcock, 1950
-New MexicoPresentIntroduced Invasive Hitchcock, 1950
-New YorkPresentIntroduced Not invasive Hitchcock, 1950
-North CarolinaPresentIntroduced Not invasive Hitchcock, 1950
-North DakotaPresentIntroduced Invasive Hitchcock, 1950
-OhioPresentIntroduced Not invasive Hitchcock, 1950
-OklahomaPresentIntroduced Invasive Hitchcock, 1950
-OregonPresentIntroduced Invasive Hitchcock, 1950
-PennsylvaniaPresentIntroduced1861 Invasive Hitchcock, 1950
-Rhode IslandPresentIntroduced Not invasive Hitchcock, 1950
-South CarolinaPresentIntroduced Not invasive Hitchcock, 1950
-South DakotaPresentIntroduced Invasive Hitchcock, 1950
-TennesseePresentIntroduced Not invasive Hitchcock, 1950
-TexasPresentIntroduced Invasive Hitchcock, 1950
-UtahWidespreadIntroduced1894 Invasive Hitchcock, 1950
-VermontPresentIntroduced Not invasive Hitchcock, 1950
-VirginiaPresentIntroduced Not invasive Hitchcock, 1950
-WashingtonWidespreadIntroduced1893 Invasive Hitchcock, 1950
-West VirginiaPresentIntroduced Not invasive Hitchcock, 1950
-WisconsinPresentIntroduced Not invasive Hitchcock, 1950
-WyomingWidespreadIntroduced1900 Invasive Hitchcock, 1950

Europe

AlbaniaPresentNative Not invasive Tutin et al., 1980
AustriaPresentIntroduced Not invasive Tutin et al., 1980
BelarusPresentNativeUSDA-ARS, 2003
BelgiumPresentIntroduced Not invasive Tutin et al., 1980
Bosnia-HercegovinaPresentNative Not invasive Tutin et al., 1980
BulgariaPresentNative Not invasive Tutin et al., 1980
CroatiaPresentNative Not invasive Tutin et al., 1980
CyprusPresentNative Not invasive Tutin et al., 1980
Czech RepublicPresentNative Not invasive Tutin et al., 1980
DenmarkPresentIntroduced Not invasive Tutin et al., 1980
EstoniaPresentIntroduced Not invasive Tutin et al., 1980
FinlandPresentIntroduced Not invasive Tutin et al., 1980
FrancePresentIntroduced Not invasive Tutin et al., 1980
-CorsicaPresentIntroduced Not invasive Tutin et al., 1980
GermanyPresentIntroduced Not invasive Tutin et al., 1980
GibraltarPresentIntroduced Not invasive Tutin et al., 1980
GreecePresentNative Not invasive Tutin et al., 1980
HungaryPresentNative Not invasive Tutin et al., 1980
ItalyPresentIntroduced Not invasive Tutin et al., 1980
LatviaPresentIntroduced Not invasive Tutin et al., 1980
LiechtensteinPresentIntroduced Not invasive Tutin et al., 1980
LithuaniaPresentIntroduced Not invasive Tutin et al., 1980
LuxembourgPresentIntroduced Not invasive Tutin et al., 1980
MacedoniaPresentNative Not invasive Tutin et al., 1980
MoldovaPresentNativeUSDA-ARS, 2003
MonacoPresentIntroduced Not invasive Tutin et al., 1980
NetherlandsPresentIntroduced Not invasive Tutin et al., 1980
NorwayPresentIntroduced Not invasive Tutin et al., 1980
PolandPresentIntroduced Not invasive Tutin et al., 1980
PortugalPresentIntroduced Not invasive Tutin et al., 1980
RomaniaPresentNative Not invasive Tutin et al., 1980
Russian FederationPresentPresent based on regional distribution.
-Central RussiaPresentNative Not invasive Tutin et al., 1980; Kostivkovsky and Young, 2000
-Southern RussiaPresentNative Not invasive Tutin et al., 1980; Kostivkovsky and Young, 2000
-Western SiberiaPresentNative Not invasive Tutin et al., 1980; Kostivkovsky and Young, 2000
SerbiaPresentNative Not invasive Tutin et al., 1980
SlovakiaPresentNative Not invasive Tutin et al., 1980
SloveniaPresentIntroduced Not invasive Tutin et al., 1980
SpainPresentIntroduced Not invasive Tutin et al., 1980
SwedenPresentIntroduced Not invasive Tutin et al., 1980
SwitzerlandPresentIntroduced Not invasive Tutin et al., 1980
UKPresentIntroduced Not invasive Tutin et al., 1980
UkrainePresentNative Not invasive Tutin et al., 1980
Yugoslavia (former)PresentNative Not invasive Tutin et al., 1980

Oceania

AustraliaRestricted distributionIntroducedRoyal Botanic Gardens Sydney, 2003; USDA-ARS, 2003
-New South WalesPresentIntroducedRoyal Botanic Gardens Sydney, 2003
-TasmaniaPresentIntroducedRoyal Botanic Gardens Sydney, 2003
-VictoriaPresentIntroducedRoyal Botanic Gardens Sydney, 2003
New ZealandPresentIntroduced1870Forde and Edgar, 1995; Owen, 1996; USDA-ARS, 2003

History of Introduction and Spread

Top of page Based on herbarium specimens in the USA, B. tectorum was first collected in Pennsylvania in 1861, Washington in 1893, Utah 1894, Colorado in 1895, and Wyoming in 1900 (Yensen, 1981). In North America in 1950, B. tectorum occurred in Alberta, Canada, Mexico, and all the mainland USA except for the far south-eastern portion of the country (Hitchcock, 1950). Today, it is found in all states including Alaska and all of the Canadian Prairie Provinces (Cronquist et al., 1977). It has also spread into northern and western Europe and North Africa. B. tectorum was first noted as an exotic species in New Zealand in 1870 (Owen, 1996), and it is also present in parts of Australia and South Africa though dates of introduction are not known. USDA-ARS (2003) notes presence in South America but without specific locations and no other reports could be located.

The history of introduction in North America is a comprehensive one. The completion of the trans-continental railroad in 1868 and the subsequent development of regional railroad networks greatly enhanced the rate of spread of exotic weed species in western North America (Young and Longland, 1996). The widespread adoption of steam powered grain threshing equipment which was moved from farm to farm was disastrous for spreading weeds. They were not cleaned between farms and the farmers saved their own grain, often contaminated with their neighbours weeds, for seed grain (Morrow and Stahlman, 1984). This process has been documented for the spread of the exotic annual Russian thistle (Salsola targus) (Young, 1988). The search for winter hardy strains of alfalfa in the late 1800s led to widespread importation of seed from central Asia under the general name of 'Turkestan' seed. These unregulated, uninspected importations were probably significant contributors to the exotic weed flora of western North America.

Yensen (1981) recreated the historical developmental of B. tectorum for southern Idaho from it being first noted as a weed in cereal grain and alfalfa fields in the early 1900s. Rural roads were little more than dirt tracks throughout the big sagebrush steppe and B. tectorum spread along these roads as a ruderal species. Periodic grading of the road surface with soil brought up from boarding burrow pits assured sufficient disturbance to provide habitats for exotic invasive weeds. After a considerable lag period as a strict ruderal species, B. tectorum was suddenly noticed to be invading degraded stands of big sagebrush where the native perennial grasses had been killed by excessive, improperly timed, and continuous grazing. When the native perennial grasses had been killed, the density of big sagebrush, which is not preferred as a browse source by domestic livestock, increased, effectively closing the sites to establishment of perennial grass seedlings even if grazing was excluded (Robertson and Pearse, 1947). B. tectorum invaded these brush stands that had virtually no herbaceous understorey and provided the fine-textured fuel with sufficient continuity of cover to ignite and allow wildfires to spread from shrub to shrub. B. tectorum populations exploded in the burned areas and effectively truncated plant succession to continued dominance by the exotic annual weeds. The agricultural economic depression that occurred after World War I brought the abandonment of many sub-marginal farms in the intermountain area of the USA. These abandoned farms were rapidly colonized by invasive exotic annual weeds which led to B. tectorum dominance. The only break in this process during the first half of the 1900s in the western USA was that the ranges were so excessively grazed that herbivory by domestic animals served to biologically suppress annual grasses (Emmerich et al., 1993).

B. tectorum on rangelands was largely confined to the big sagebrush zone from its introduction until the 1980s. This zone is characterized by annual precipitation of 200-350 mm and loam-textured surface soils that are not affected by accumulations of soluble salts. During the 1980s, B. tectorum suddenly spread to the salt deserts of the intermountain area (Young and Tipton, 1990). As the name implies, these areas are characterized by salt-affected soils and annual precipitation of 100-150 mm. The spread of B. tectorum into these areas made possible wildfires as a stand renewal process for the first time. At about the same time, B. tectorum also spread into higher elevation, higher precipitation coniferous woodlands. Within the sagebrush zone, B. tectorum became a much more dominant species as grazing management systems were implemented that included rotational deferment until after seed ripening or a complete year-long rest from grazing. This abundance of B. tectorum fuel led to the occurrence of regional firestorms that burned huge areas of rangelands in a very short period of time.

Risk of Introduction

Top of page Planting contaminated seed and feeding contaminated hay or grain to livestock are common means of dispersal of B. tectorum. In most of the USA, B. tectorum is not a regulated noxious weed meaning that it can occur in seed lots as long as it does not exceed the 'other weed species' limit, applying even to certified seed lots. As such, it is likely to spread to other areas where it is not yet present as a seed contaminant. For example, the revegetation of the right-of-way for a natural gas pipe line in Alberta, Canada by seeding certified crested wheatgrass seed grown in Idaho, USA, resulted in a strip of B. tectorum across the south-eastern Alberta prairie. The transactions involved in purchasing the seed were all perfectly legal because B. tectorum fell under the 'other weed species' category in the USA. Even if you purchase certified seed, it is worthwhile to have the seed sampled to identify the non-legally noxious weed seeds that may contaminate the seed lot.

Habitat

Top of page It is an opportunistic species with few absolutely restrictive requirements. B. tectorum is such a widespread species you should not be surprised where one may encounter the species, even in your socks (WSSA, 2003). B. tectorum is an exotic invasive annual grass in North America (Klemmedson and Smith, 1964). In the semi-arid to arid environments of western North America it is found in environments similar to central Asia where it originally evolved. B. tectorum is often described as a classic ruderal species found along roads, fence lines, and irrigation structures. B. tectorum currently dominates millions of hectares of degraded rangelands in the intermountain area between the Sierra-Cascade and Rocky Mountains in western North America. The bulk of this area was formerly big sagebrush (Artemisia tridentata)/native perennial bunch (caespitose) grass plant communities (Hull and Pechanec, 1947). B. tectorum dominance ranges from portions of the salt desert shrub steppe through the big sagebrush/bunchgrass zone to coniferous woodlands and even to true native perennial grasslands. Generally, the habitat of B. tectorum is described as disturbed plant communities, Daubenmire (1940) conclusively demonstrated that this exotic annual grass could invade high ecological condition bluebunch wheatgrass (Pseudoroegneria spicatum) communities that had always been protected by grazing by large herbivores.

Habitat List

Top of page
CategoryHabitatPresenceStatus
Terrestrial-managed
Cultivated / agricultural land Present, no further details Harmful (pest or invasive)
Disturbed areas Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Managed grasslands (grazing systems) Present, no further details Harmful (pest or invasive)
Rail / roadsides Present, no further details Harmful (pest or invasive)
Urban / peri-urban areas Present, no further details Harmful (pest or invasive)
Terrestrial-natural/semi-natural
Deserts Present, no further details Harmful (pest or invasive)
Natural forests Present, no further details Harmful (pest or invasive)
Natural grasslands Present, no further details Harmful (pest or invasive)
Riverbanks Present, no further details Harmful (pest or invasive)

Hosts/Species Affected

Top of page It is a very serious agronomic weed in winter wheat (Triticum aestivum) fields of the Pacific Northwest and the central and southern Great Plains of the USA (Young et al., 1984). Although the crop and season of planting are the same, the Pacific Northwest and the Great Plains of the USA have grossly different climates. The weed causes tremendous yield losses in winter wheat and barley (Hordeum vulgare) production and is a spring weed problem in alfalfa (Medicago sativa) hay production. It is a very troublesome species in bluegrass (Poa pratensis) seed production fields. B. tectorum is also a serious problem on rangelands, and often encountered as a weed of orchards and vineyards.

Host Plants and Other Plants Affected

Top of page

Biology and Ecology

Top of page Reproductive Biology

The breeding system of B. tectorum is apparently an example of that theorized by Allard (1965) for largely self-pollinated species of annual grasses that are environmentally conditioned to occasional out-crossing. Under this breeding system, if an individual B. tectorum plant is introduced to a site where genotypically it is a good fit to the environmental potential of the site, it populates the site with offspring with stable duplicates of the desirable genotype through self fertilization. A healthy amplitude for phenotypic plasticity helps this one-fits-all genotype to be very successful. Occasionally, environmental conditions would be adequate to allow these self-pollinated species to cross-pollinate and produce hybrid offspring (Allard, 1965). In applying this concept to B. tectorum, Young and Evans (1976) took an additional step and suggested that for the first generation after hybridization, the offspring would express heterosis because essentially two inbred lines selected for survival in the environment of residency were being crossed. The population density of B. tectorum on a range site that has not burned for several years is 5000-10,000 plants per m² (Young et al., 1969), but which may shrink to 10 plants per m² following a wildfire. The reduction in herbaceous plant density coupled with the loss of perennial shrubs after fire, combine to enable each B. tectorum plant to have a much greater potential to spread and the resulting B. tectorum plants are huge in comparison to those that existed in dense stands before the wildfire. The post-fire B. tectorum plants produce multiple tillers that extend flowering over a prolonged period and the decreased plant density allows a greater amount of soil moisture per B. tectorum plant. Improved moisture relations, which normally limits B. tectorum growth, increases the chances that the floret will be sufficiently open to allow the anthers to be exerted.

Physiology and Phenology

B. tectorum can either be a true annual with germination in early spring and reaching maturity in the early summer of the same year, or a winter annual with germination in the autumn, over-wintering as a flat rosette of leaves on the soil surface and sending up flowering tillers the next spring (Harris, 1967). In the Pacific Northwest, USA, autumn germination occurs every year and B. tectorum is a true winter annual which is why it is so competitive with winter wheat. In the Great Basin, USA, B. tectorum germinates in the autumn about once every 5 years. With either autumn or early spring germination, B. tectorum tillers begin rapid elongation from mid-April to mid-May. Most accessions of B. tectorum plants require vernalization before they will flower (Hulbert, 1955; Finnerty and Klingman, 1962), achieved by germinating seeds at 5°C. B. tectorum plants in the field will always flower if soil moisture is available; and most accessions collected from salt desert environments will flower in the greenhouse without vernalization. Phenology of B. tectorum plants is extremely variable depending on field environmental conditions. Flowering can initiate as early as late April or as late as early July on the same site in different years.

B. tectorum seeds are initially not dormant at maturity, or may have short-term after-ripening requirements (Young et al., 1969; Milby and Johnson, 1987). Only a small portion of the annual seed production is required to provide plants that completely occupy a given area the next season. B. tectorum seeds that do not find safe sites for germination acquire a dormancy that permits the building of seedbanks and it is the development of these seedbanks that makes the control of B. tectorum such a prolonged and difficult problem. The acquired seed dormancy breaks down gradually over 3-5 years. Germination of seeds with the acquired dormancy can be enhanced by enrichment of the germination substrate with nitrate or gibberellin. B. tectorum seeds have specific requirements for safe sites for germination. The seeds have very low germination rates on the surface of seedbeds in semi-arid or arid environments. Litter coverage or micro-topography in the seedbed surface is required for successful germination under field conditions (Evans and Young, 1970, 1972). B. tectorum seeds can germinate at very cold seedbed temperatures (Evans et al., 1970) and germination will occur at a constant 0°C or alternating temperatures to as low as 0°C (Young and Evans, 1982).

Very small amounts of nitrogen have large influences on the dynamics of B. tectorum populations. Fertilization with ammonium sulphate over a stand of established perennial grasses, with B. tectorum as a component of the community, can result in the death of the perennials as B. tectorum out-competes the perennials for soil moisture (Kay and Evans, 1965). Fertilization of B. tectorum stands without perennial grasses can result in extreme increases in herbage production (Kay, 1966). Immobilization of nitrogen with a carbon source or the inhibition of nitrification severely decreases the establishment and growth of B. tectorum populations (Young et al., 1998a). This aspect of B. tectorum physiology has not been developed into a commercially successful control measure, but the reciprocal (fertilization with nitrogen) certainly enters into the management of this species. In the reclamation of mining spoils in the USA, it appears to be desirable to add nitrogen fertilizers to raw rock dump spoils but such fertilization will always create a B. tectorum problem (Young et al., 1998b).

Environmental Requirements

B. tectorum has successfully invaded so many contrasting environments in North America it is obviously a generalist in terms of environmental requirements. This is accomplished through great phenotypic plasticity and secondly through the apparent potential to rapidly evolve new genotypes. Generally, B. tectorum thrives as a winter annual, but germination in the autumn is not essential for the annual grass to persist. It is not a dominant species in truly warm deserts, even those with some winter precipitation. B. tectorum occurs, but is not a dominant annual grass in the mild Mediterranean climates of cis-montane California and southwestern Oregon, USA. B. tectorum has invaded the salt deserts of the Intermountain Area of western North America, but the true level of tolerance to salt-affected soil is not known with precision. Precipitation, both the amount received and the periodicity of moisture events are critical factors in the population density, herbage and seed production. On rangelands, B. tectorum populations can disappear over vast areas for as long as 3 years during droughts, but they will return when the drought ends.

Associations

On rangelands, B. tectorum is closely associated with the seral continuum it often culminates. This continuum is largely composted of exotic annual herbaceous broadleaved and grass species. B. tectorum can truncate succession in this continuum for extended periods of time (at least 75 years). However, the B. tectorum-dominated sites are open to the invasion by other exotic annuals, biannual, or perennial weed species. B. tectorum can be grazed to the point it is replaced by lower seral stages dominated by broadleaf herbaceous exotic weeds, but if the grazing pressure is relaxed, B. tectorum returns as the dominant species (Young et al., 1969).

Air Temperature

Top of page
Parameter Lower limit Upper limit
Absolute minimum temperature (ºC) -40
Mean annual temperature (ºC) 5 15
Mean maximum temperature of hottest month (ºC) 30 40
Mean minimum temperature of coldest month (ºC) -5 0

Rainfall

Top of page
ParameterLower limitUpper limitDescription
Dry season duration35number of consecutive months with <40 mm rainfall
Mean annual rainfall100650mm; lower/upper limits

Rainfall Regime

Top of page Winter

Soil Tolerances

Top of page

Soil drainage

  • free

Soil reaction

  • alkaline
  • neutral

Soil texture

  • heavy
  • light
  • medium

Special soil tolerances

  • infertile
  • saline
  • shallow

Notes on Natural Enemies

Top of page B. tectorum plants become infested with smut (Ustilago spp.) in certain years, but there is no evidence that natural infections have any lasting influence of the persistence or dominance of B. tectorum populations (Stewart and Hull, 1949). The seed pathogen Podosporiella verticillate is probably very significant in reducing viable B. tectorum seeds in seedbanks (Kreitlow and Bleak, 1964; Young et al., 1969).

Means of Movement and Dispersal

Top of page Natural Dispersal (Non-Biotic)

B. tectorum seeds are too heavy for wind to be a major factor in dispersal.

Vector Transmission (Biotic)

On rangelands, rodents collect and scatter hoarded seeds of B. tectorum (LaTourrette et al., 1971). Rodents recover seeds from some of these caches for consumption, while others germinate and produce viable seeds. The barbs on the lemma, palea, and awns of B. tectorum caryopses are very effective in aiding seed dispersal. The seeds stick in animal fur and also human clothing.

Agricultural Practices

Planting contaminated seed and feeding contaminated hay or grain to livestock are common means of dispersal of B. tectorum. In most of the USA, B. tectorum is not a regulated noxious weed meaning that it can occur in seed lots as long as it does not exceed the 'other weed species' limit, applying even to certified seed lots.

Accidental Introduction

Planting contaminated seed and feeding contaminated hay or grain to livestock are common means of dispersal of B. tectorum. The use of B. tectorum-infested cereal straw in erosion control during construction projects is a common means of dispersal for this species. Also, accidental dispersal by farmers or walkers is another means, because if you walk through a B. tectorum stand at seed maturity, you rapidly find your socks full of seeds unless you are wearing tall boots.

Intentional Introduction

There are folk stories that B. tectorum was deliberately spread by stockmen in the Intermountain Area, USA, after the native perennial grasses were severely depleted by excessive grazing although these stories have never been documented or verified. The invasion rate of B. tectorum is sufficiently fast enough that intentional enhancement by humans was probably not necessary.

Pathway Vectors

Top of page
VectorNotesLong DistanceLocalReferences
Clothing, footwear and possessionsSocks Yes
Containers and packaging - woodAll Yes
Land vehiclesAll Yes
Plants or parts of plantsAll Yes
Soil, sand and gravelTop soil, mine and construction spoils Yes

Plant Trade

Top of page
Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
True seeds (inc. grain) seeds

Impact Summary

Top of page
CategoryImpact
Animal/plant collections None
Animal/plant products Negative
Biodiversity (generally) Negative
Crop production Negative
Environment (generally) Negative
Fisheries / aquaculture None
Forestry production Negative
Human health Negative
Livestock production None
Native fauna None
Native flora Negative
Rare/protected species Negative
Tourism None
Trade/international relations Negative
Transport/travel None

Impact

Top of page It is estimated that as few as 100 B. tectorum plants/m² reduced winter wheat production by 27-36% (Young et al., 1984) and B. tectorum is a major problem in winter cereal production in North America. B. tectorum infests an estimated 5.7 million ha of cropland in the western USA and control measures cost US$350 million dollars annually (Mitch and Kyser, 1987; Ogg, 1994). Wildfires fuelled by B. tectorum are also a significant economic cost. For example, in Nevada, USA during a 10-day period in 1999, 0.64 million ha of rangeland burned in wildfires largely fuelled by B. tectorum. It cost US$38 million to suppress these fires and US$42 million in emergency restoration efforts on the burned area (Young and Sparks, 2002). Similar wildfire events are repeated in various portions of the Intermountain Area, USA annually.

Environmental Impact

Top of page B. tectorum increases the chances of ignition, rate of spread and expanding the season of wildfires, reducing the interval between re-occurring fires. The effect is to eliminate native woody species and truncate succession among herbaceous species to leave B. tectorum as the dominant species. At the same time, B. tectorum-dominated communities remain open to invasion by other exotic, invasive weeds. Accumulations of B. tectorum herbage mature in late spring and increase the chance of ignition and the rate of spread of wildfires. The natural wildfire season started in mid August when the herbage of native perennial grasses matured. The early maturity of B. tectorum extends the wildfire season through the warmest periods of the summer. B. tectorum provides the continuity fuel that allows the spread of wildfires from shrub to shrub. Such wildfires are a threat to human life and property, destroy the native sagebrush plants that do not re-sprout after the aerial portion of the plant is burned, destroy valuable forage resources, and the resulting burns are subject to accelerated wind and water erosion.

Impact: Biodiversity

Top of page The noted American plant ecologist, DW Billings, termed B. tectorum a biotic cause of ecosystem impoverishment (Billings, 1989). In rangelands in the western USA, B. tectorum is a landscape level problem. B. tectorum closes plant communities to the recruitment of seedlings of native plant species (Robertson and Pearse, 1945) and this competition effectively truncates succession assuring prolonged dominance by B. tectorum.

Threatened Species

Top of page
Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Astragalus anserinus (Goose Creek milkvetch)NatureServe NatureServe; USA ESA candidate species USA ESA candidate speciesIdaho; Nevada; UtahEcosystem change / habitat alterationUS Fish and Wildlife Service, 2014a
Astragalus microcymbus (skiff milkvetch)NatureServe NatureServe; USA ESA candidate species USA ESA candidate speciesColoradoCompetition (unspecified)US Fish and Wildlife Service, 2014b
Astragalus schmolliae (Schmoll's milkvetch)CR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); NatureServe NatureServe; USA ESA candidate species USA ESA candidate speciesColoradoEcosystem change / habitat alterationUS Fish and Wildlife Service, 2015
Castilleja cinerea (ash-grey paintbrush)NatureServe NatureServe; USA ESA listing as threatened species USA ESA listing as threatened speciesCaliforniaCompetition - smotheringUS Fish and Wildlife Service, 2013a
Centrocercus minimus (Gunnison sage-grouse)USA ESA listing as threatened species USA ESA listing as threatened speciesColorado; UtahEcosystem change / habitat alterationUS Fish and Wildlife Service, 2013b
Centrocercus urophasianus (greater sage-grouse)NT (IUCN red list: Near threatened) NT (IUCN red list: Near threatened)California; Colorado; Idaho; Montana; Nevada; North Dakota; Oregon; South Dakota; Utah; WyomingCompetition (unspecified); Ecosystem change / habitat alterationUS Fish and Wildlife Service, 2013c
Eremogone ursina (Bear Valley sandwort)NatureServe NatureServe; USA ESA listing as threatened species USA ESA listing as threatened speciesCaliforniaCompetition (unspecified)US Fish and Wildlife Service, 2007a
Eriogonum soredium (Frisco buckwheat)NatureServe NatureServe; USA ESA candidate species USA ESA candidate speciesUtahCompetition (unspecified); Ecosystem change / habitat alterationUS Fish and Wildlife Service, 2014c
Lepidium ostleri (Ostler's peppergrass)NatureServe NatureServe; USA ESA candidate species USA ESA candidate speciesUtahCompetition (unspecified); Ecosystem change / habitat alterationUS Fish and Wildlife Service, 2014d
Mirabilis macfarlaneiNatureServe NatureServe; USA ESA listing as threatened species USA ESA listing as threatened speciesIdaho; OregonCompetition - monopolizing resources; Ecosystem change / habitat alterationUS Fish and Wildlife Service, 2000
Penstemon grahamii (Graham's beardtongue)NatureServe NatureServe; USA ESA species proposed for listing USA ESA species proposed for listingColorado; UtahCompetition - stranglingUS Fish and Wildlife Service, 2005
Sclerocactus brevispinusCR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); USA ESA listing as threatened species USA ESA listing as threatened speciesUtahCompetition - monopolizing resourcesUS Fish and Wildlife Service, 2010a
Sclerocactus wetlandicusUSA ESA listing as threatened species USA ESA listing as threatened speciesUtahCompetition - monopolizing resourcesUS Fish and Wildlife Service, 2010b
Silene spaldingii (Spalding's catchfly)USA ESA listing as threatened species USA ESA listing as threatened speciesIdaho; Montana; Oregon; WashingtonCompetition - monopolizing resourcesUS Fish and Wildlife Service, 2007b
Stephanomeria malheurensis (Malheur wire-lettuce)USA ESA listing as endangered species USA ESA listing as endangered speciesOregonCompetition - stranglingUS Fish and Wildlife Service, 1991
Taraxacum californicum (California taraxacum)USA ESA listing as endangered species USA ESA listing as endangered speciesCaliforniaCompetition - stranglingUS Fish and Wildlife Service, 2008
Trifolium friscanum (Frisco clover)USA ESA candidate species USA ESA candidate speciesUtahCompetition - monopolizing resources; Ecosystem change / habitat alterationUS Fish and Wildlife Service, 2014e
Urocitellus endemicus (southern Idaho ground squirrel)No DetailsIdahoEcosystem change / habitat alterationUS Fish and Wildlife Service, 2014f

Social Impact

Top of page B. tectorum probably has the highest name recognition among exotic, invasive weeds in the Intermountain Area, USA and even suburban and urban residents fear wildfires fuelled by B. tectorum. The seeds often cause injury to the ears, eyes and mouths of pets such as dogs and horses as well as to humans. Livestock such as cattle and sheep can also be injured.

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Highly adaptable to different environments
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Highly mobile locally
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Damaged ecosystem services
  • Ecosystem change/ habitat alteration
  • Negatively impacts agriculture
  • Negatively impacts human health
  • Negatively impacts animal health
  • Negatively impacts tourism
  • Reduced amenity values
  • Reduced native biodiversity
Impact mechanisms
  • Competition - monopolizing resources
  • Competition - smothering
  • Competition - strangling
  • Competition
  • Produces spines, thorns or burrs
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally

Uses

Top of page B. tectorum is the most abundant forage species on many intermountain area rangelands of the USA (Murray and Klemmedson, 1968) and this was true by at least the mid 1900s (Fleming et al., 1942). There are many disadvantages to basing a range livestock industry on B. tectorum versus perennial grasses, but grazing B. tectorum is a reality on millions of hectares of rangelands in North America.

Similarities to Other Species/Conditions

Top of page There are a host of annual Bromus spp. with more or less similar ecological requirements that can be associated with B. tectorum in specific environments. In the southern intermountain area of the USA, red brome (Bromus madritensis ssp. rubens) replaces B. tectorum and introgressive hybrids may exist. Occasionally, Japanese brome (B. japonicus), ripgut (B. diandrus), or rattlesnake brome (B. briziformis) may occur in the same communities as B. tectorum, but once in flower it is easy to distinguish the different species of Bromus spp. The only native annual grass that can be confused with B. tectorum in the seedling stage is six weeks fescue (Vulpia octoflora). The juvenile foliage of six weeks fescue is much finer in texture and the plants more diminutive than B. tectorum. Annual wheatgrass (Eremopyrun triticeum) is becoming increasingly abundant in B. tectorum stands in the intermountain area. At maturity the compact spike of this grass is so different from the nodding panicle of B. tectorum there is no problem in identification. Vegetatively, annual wheatgrass has so few leaves it does not resemble B. tectorum. Over vast areas of rangelands, B. tectorum has been replaced by medusahead (Taeniatherum caput-medusae). The seed, foliage, seed heads, and phenology of medusahead make it easy to distinguish from B. tectorum, and matures 2-4 weeks later than B. tectorum making infestations easy to distinguish from a considerable distance. In winter wheat fields in the Pacific Northwest, USA, jointed goatgrass (Aegilops cylindrica) has become a serious winter annual weed in addition to B. tectorum.

Prevention and Control

Top of page Cultural Control

On rangelands, the establishment of perennial grasses effectively suppresses B. tectorum so that it remains persistent, but only as a minor component of vegetation communities. The problem with this approach is in the establishment of perennial grass seedlings in the face of competition from B. tectorum, and which was found to be almost impossible in western North America. During the 1940s it was determined that the exotic perennial crested wheatgrass (Agropyron desertorum) could be established on sagebrush rangelands (Young and McKenzie, 1982) and although weed control is still required for its establishment, seedlings are much more competitive compared to those of the native perennial grasses. In areas of winter wheat production, if cultural, environmental, and economic restraints permit, periodic switching to spring-planted cereal grains permits suppression by herbicide application or tillage before planting of the grain crop. In addition, immobilization of nitrogen followed by planting seeds of a non-leguminous native shrub, antelope bitterbrush (Purshia tridentata) that symbiotically fixes nitrogen, has been highly successful on B. tectorum infested rangelands (Young and Clements, 2002).

Mechanical Control

On rangelands and much of the winter wheat production areas in the USA, deep mouldboard ploughing to bury the B. tectorum seedbank is not physically or economically feasible. Post-emergence mechanical tillage as a seedbed preparation is feasible, but on arid rangelands this forces a delay in planting until sufficient B. tectorum has emerged for the tillage to have sufficient efficacy before the onset of the summer drought.

Chemical Control

On rangelands in the western USA, there are two basic approaches for the use of herbicides for control of B. tectorum as a means of establishing seedlings of perennial grasses. The first system is to wait until a significant portion of the germinable seeds of B. tectorum have emerged in the early spring and then apply a contact herbicide such as paraquat (Evans et al., 1967). Seeding of perennial grass could be carried out simultaneously with the sprayer mounted on the front of the drill. This practice never became popular because of paraquat toxicity to humans and the failure to apply it aerially, and glyphosate was not a good substitute for paraquat probably because of the delay in B. tectorum mortality during the cold spring period after application of this herbicide. The second system involves the creation of a fallow with herbicides, with atrazine applied in October or November and B. tectorum controlled during the following growing season with the site being seeded to perennial grasses the following October, one year after the application of the herbicide (Eckert and Evans, 1967). If the summer rains are good in the fallow year, lower successional levels of exotic invasive broadleaved weeds will flourish on the fallow and certainly during the seedling year of the perennial grasses.

In winter cereal production, B. tectorum germinates very close to the same time as the winter wheat or barley (Ogg, 1994). Selective control of B. tectorum during the first 3 weeks following emergence is critical in reducing competition. In conventionally tilled wheat, diclofop has been the most effective soil-applied herbicide for control of B. tectorum, killing B. tectorum as it germinates and reducing B. tectorum populations by up to 95% allowing wheat yields to increase by 30-40% (Stahlman, 1984).

Metribuzin is the only herbicide available that when applied post-emergence will control B. tectorum selectively in winter wheat (Swan and Whitesides, 1988), but to be effective it must be applied before the weed begins to tiller extensively. The margin of crop safety with metribuzin is very narrow and is based on the ability of wheat to metabolize metribuzin rapidly and its ability to root deeply early in its life cycle and thus avoid uptake of the herbicide (Devlin et al., 1987). The use of metribuzin in wheat is restricted to fine textured soils with more than 1% organic matter (Ogg, 1994). A special formulation of atrazine was used in the Pacific Northwest, USA, to reduce B. tectorum in winter wheat, and applied before the wheat was seeded with the seeding done with a deep furrow drill. The openers on the drill moved the herbicide on the soil surface to the side and B. tectorum was controlled between, but not within the rows (Ogg, 1994).

Much of the winter wheat production in the Pacific Northwest of the USA takes place on fine textured, aeolian soils, often on steep slopes and erosion is a serious problem. Conservation tillage practices that leave litter to protect the soil surface may have promoted an increase in B. tectorum, considering the seedbed ecology of the species (Evans and Young, 1970). Winter wheat production without tillage (no-till) has significant popularity in the Pacific Northwest. In no-till winter wheat a granular formulation of triallate plus trifluralin applied to the soil surface before planting has controlled B. tectorum (Ogg, 1994). The granulars are not absorbed by litter on the soil surface so they are more effective than liquid applications and a deep furrow drill is necessary to move the herbicide away from the wheat seeds.

Biological Control

Classical biological control of grasses such as B. tectorum poses problems regarding specificity, noting that many crops are also grasses. There has been considerable interest in using naturally occurring soil micro-organisms for weed control (Grey et al., 1995), with Kennedy (1994) having screened thousands of isolates of soil bacteria for the inhibition of B. tectorum germination or seedling growth. Several isolates were found that slow the root growth of B. tectorum giving wheat a competitive advantage (Kennedy et al., 1989, 1991), but the practical problem with application of mycoherbicides is in obtaining infection in the field. B. tectorum can be infested with smut (Ustilago spp.), and Meyer et al. (2001) proposed the use of U. bullata as a biological control agent for B. tectorum.

Integrated Control

In the Pacific Northwest, USA, some winter wheat farmers appear to tolerate the presence of B. tectorum whereas others are destroyed by the weed. Those that successfully suppress B. tectorum maintain an active programme that identifies and maps infestations. Rotation to spring-planted cereal crops on infested fields is used to reduce seedbanks. Contact herbicides are used to control spot infestations and herbicidal control practices used correctly in winter wheat stands help to reduce competition from B. tectorum. On rangelands, ranchers can graze B. tectorum infestations or watch them eventually burn in uncontrollable wildfires. Grazing management that involves rest from grazing or deferment of grazing until after seed ripening of B. tectorum have proven to be disasters. Weed control to allow establishment of perennial grasses followed by quality grazing management relegates B. tectorum to a minor species in most rangeland communities.

References

Top of page

Allard RW, 1965. Genetic systems associated with colonizing ability in predominantly self-pollinated species. In: Baker HG, Stebbins GL, eds. The Genetics of Colonizing Species. New York, USA, Academic Press, 49-75

Billings WD, 1989. Bromus tectorum, a biotic cause of ecosystem impoverishment. In: Woodwell GM, ed. The Earth in Transitions: Patterns and Processes of Biotic Impoverishment. New York, USA:Cambridge University Press, 210-284

Cronquist A, Holmgren AH, Holmgren NH, Reveal JL, Holmgren PK, 1977. Intermountain Flora. Vol.6. New York, USA: Columbia University Press

Daubenmire RF, 1940. Plant succession due to overgrazing in the Agropyron bunchgrass prairie of southeastern Washington. Ecology, 21:55-64

Devlin DL, Gealy DR, Morrow LA, 1987. Differential metabolism of metribuzin by downy brome (Bromus tectorum) and winter wheat (Triticum aestivum). Weed Science, 35(6):741-745

Eckert RE, Evans RA, 1967. A chemical-fallow technique for control of downy brome and establishment of grasses on rangelands. Journal of Range Management, 20:35-41

Emmerich FL, Tipton FH, Young JA, 1993. Cheatgrass: changing perspective and management strategies. Rangelands, 15:37-40

Evans RA, Eckert RE, Kay BL, 1967. Wheatgrass establishment with paraquat and tillage on downy brome ranges. Weeds, 15:50-55

Evans RA, Holbo HR, Eckert RE, Young JA, 1970. Influence of weed control and seedling methods on the functional environment of rangelands. Weed Science, 18:154-162

Evans RA, Young JA, 1970. Plant litter and establishment of alien annual weed species in rangeland communities. Weed Science, 18:697-703

Evans RA, Young JA, 1972. Microsite requirements for establishment of annual rangeland weeds. Weed Science, 20(4):350-356

Finnerty DW, Klingman DI, 1962. Life cycles and control studies of some weed bromegrasses. Weeds, 10:40-47

Fleming CE, Shipley MA, Miller MR, 1942. Bronco grass on Nevada ranges. Bulletin 159. Reno, USA: Agricultural Experiment Station, University of Nevada

Forde MB, Edgar E, 1995. Checklist of pooid grasses naturalised in New Zealand. 3. Tribes Bromeae ad Brachypodieae. New Zealand Journal of Botany 33:35-42

Grey WE, Quimby PCJr, Mathre DE, Young JA, 1995. Potential for biological control of downy brome (Bromus tectorum) and medusahead (Taeniatherum caput-medusae) with crown and root rot fungi. Weed Technology, 9(2):362-365; 12 ref

Harris GA, 1967. Some competitive relationships between Agropyron spicatum and Bromus tectorum. Ecological Monographs, 37:89-111

Hitchcock AS, 1950. Manual of the grasses of the United States. USDA Miscellaneous Publication 200. Washington, D.C., USA: USDA

Hulbert LC, 1955. Ecological studies of Bromus tectorum and other annual bromegrasses. Ecological Monographs, 25:181-213

Hull AC, Pechanec JF, 1947. Cheatgrass-challenge to range research. Journal of Forestry, 45:555-564

Kay BL, 1966. Fertilization of cheatgrass ranges in California. Journal Range Management, 19:217-220

Kay BL, Evans RA, 1965. Effects of fertilization on a mixed stand of cheatgrass and intermediate wheatgrass. J. Range Management, 18:7-11

Kennedy AC, 1994. Biological control of annual grass weeds. In: Monsen SB, Kitchen SG, eds. Ecology and Management of Annual Rangelands. General Technical Report No. INT-313. Ogden, USA; Intermountain Research Station, USDA Forest Service, 186-189

Kennedy AC, Elliott LF, Young FL, Douglas CL, 1991. Rhizobacteria suppressive to the weed downy brome. Soil Science Society of America Journal, 55(3):722-727

Kennedy AC, Stubbs, TL, Young FL, 1989. Rhizobacterial colonization of winter wheat and grass weeds. Agronomy Abstracts, 53:220

Klemmedson JO, Smith JG, 1964. Cheatgrass. Botanical Review April-June:226-262

Kostivkovsky V, Young JA, 2000. Invasive exotic rangeland weeds: a glimpse at some of their native habitats. Rangelands, 22(6):3-6

Kreitlow LW, Bleak AT, 1964. Podosporiella verticillate, a soil-borne pathogen of some western Gramineae. Phytopathology, 54:353-357

LaTourrette JE, Young JA, Evans RA, 1971. Seed dispersal in relation to rodent activities in seral big sagebrush communities. Journal of Range Management, 24:118-120

Meusel H, Jäger E, Weinert E, 1965. Vergleichende Chorologie der zentraleuropäischen Flora. Jena, Germany: Fischer

Meyer SE, Nelson DL, Clement S, 2001. Evidence for resistance polymorphism in the Bromus tectorum - Ustilago bullata pathosystem: implications for biocontrol. Canadian Journal of Plant Pathology, 23(1):19-27; 37 ref

Milby TH, Johnson FL, 1987. Germination of downy brome from southern Kansas, central Oklahoma and north Texas. Journal of Range Management, 40(6):534-536

Mitch LW, Kyser GB, 1987. WSWS survey of common and troublesome weeds in twelve western states. Western Society Weed Science, 40:36-59

Morrow LA, Stahlman PW, 1984. The history and distribution of downy brome (Bromus tectorum) in North America. Weed Science, 32(Suppl. 1):2-6

Murray RR, Klemmedson JO, 1968. Cheatgrass range in southern Idaho: seasonal cattle gains and grazing capacities. Journal of Range Management, 24:308-313

Ogg AG Jr, 1994. A review of the chemical control of downy brome. General Technical Report - Intermountain Research Station, USDA Forest Service Ogden, USA; Intermountain Research Station, USDA Forest Service, No. INT-313:194-196

Owen SJ, 1996. Ecological weeds on conservation land in New Zealand: A database. Department of Conservation, Wellington, New Zealand: DOC Science Publications. http://www.hear.org/weedlists/other_areas/nz/nzecoweeds.htm

Robertson JH, Pearse CK, 1945. Artificial seeding and the closed community. Northwest Science, 14:38-66

Royal Botanic Gardens Sydney, 2003. Australia's Virtual Herbarium. Sydney, Australia: Royal Botanic Gardens. http://plantnet.rbgsyd.gov.au/cgi-bin/avh/avh.cgi

Stahlman PW, 1984. Downy brome (Bromus tectorum) control with diclofop in winter wheat (Triticum aestivum). Weed Science, 32(1):59-62

Stewart G, Hull AC, 1949. Cheatgrass (Bromus tectorum L.): An ecological intruder in southern Idaho. Ecology, 30:58-74

Swan DG, Whitesides RE, 1988. Downy brome (Bromus tectorum) control in winter wheat. Weed Technology, 2(4):481-485

Taylor RL, MacBryde B, 1977. Vascular plants of British Columbia: A descriptive resource inventory. Technical Bulletin No. 4. The Botanical Garden, Vancouver, Canada: University of British Columbia Press, 745 pp

Tutin TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM, Webb DA, 1980. Flora Europaea. Volume 5. Alismataceae to Orchidaceae (Monocotyledones). Cambridge, UK: Cambridge University Press, 452pp

US Fish and Wildlife Service, 1991. Stephanomeria malheurensis (Malheur Wire lettuce) Recovery Plan. In: Stephanomeria malheurensis (Malheur Wire lettuce) Recovery Plan : US Fish and Wildlife Service.29 pp. + appendices.

US Fish and Wildlife Service, 2000. Revised Recovery Plan for Macfarlanes Four-O'Clock (Mirabilis macfarlanei). In: Revised Recovery Plan for Macfarlanes Four-O'Clock (Mirabilis macfarlanei) : US Fish and Wildlife Service.56 pp. https://ecos.fws.gov/docs/recovery_plan/000630.pdf

US Fish and Wildlife Service, 2005. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Penstemon grahamii. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Penstemon grahamii : US Fish and Wildlife Service.10 pp. http://ecos.fws.gov/docs/candidate/assessments/2005/r6/Q1DI_P01.pdf

US Fish and Wildlife Service, 2007. Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Arenaria ursina (Bear Valley Sandwort), Castilleja cinerea (Ash-gray Indian Paintbrush), and Eriogonum kennedyi var. austromontanum (Southern Mountain Wild-Buckwheat). In: Federal Register : US Fish and Wildlife Service.73092 -73178. https://www.federalregister.gov/articles/2007/12/26/07-6137/endangered-and-threatened-wildlife-and-plants-designation-of-critical-habitat-for-arenaria-ursina

US Fish and Wildlife Service, 2007. Recovery Plan for Silene spaldingii (Spalding's Catchfly). In: Recovery Plan for Silene spaldingii (Spalding's Catchfly) : US Fish and Wildlife Service.203 pp. http://ecos.fws.gov/docs/recovery_plan/071012.pdf

US Fish and Wildlife Service, 2008. Taraxacum californicum (California taraxacum). Five-Year Review: Summary and Evaluation. In: Taraxacum californicum (California taraxacum). Five-Year Review: Summary and Evaluation : US Fish and Wildlife Service.26 pp.

US Fish and Wildlife Service, 2010. Recovery Outline for the Sclerocactus brevispinus (Pariette Cactus). In: Recovery Outline for the Sclerocactus brevispinus (Pariette Cactus) : US Fish and Wildlife Service.17 pp. http://ecos.fws.gov/docs/recovery_plan/Pariette%20Cactus_Recovery%20Outline_Apr%202010.pdf

US Fish and Wildlife Service, 2010. Recovery Outline for the Sclerocactus wetlandicus (Uinta Basin Hookless Cactus). In: Recovery Outline for the Sclerocactus wetlandicus (Uinta Basin Hookless Cactus) : US Fish and Wildlife Service.15 pp. http://ecos.fws.gov/docs/recovery_plan/Sclerocactus%20wetlandicus%20recovery%20outline_final_Apr%202010.pdf

US Fish and Wildlife Service, 2013. Castilleja cinerea (Ash-gray Paintbrush). 5-Year Review: Summary and Evaluation. In: Castilleja cinerea (Ash-gray Paintbrush). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.45 pp. http://ecos.fws.gov/docs/five_year_review/doc4138.pdf

US Fish and Wildlife Service, 2013. Endangered and Threatened Wildlife and Plants; Endangered Status for Gunnison Sage-Grouse; Proposed Rule. In: Federal Register , 78(8) : US Fish and Wildlife Service.2486-2538. https://www.gpo.gov/fdsys/pkg/FR-2013-01-11/pdf/2012-31667.pdf

US Fish and Wildlife Service, 2013. Sage-grouse, Sagebrush and the Threat Posed by Invasive Annual Grasses/Increased Fire Frequency. In: Sage-grouse, Sagebrush and the Threat Posed by Invasive Annual Grasses/Increased Fire Frequency : US Fish and Wildlife Service.2 pp. http://www.fws.gov/mountain-prairie/factsheets/Inv_Fire_101813.pdf

US Fish and Wildlife Service, 2014. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus anserinus. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus anserinus : US Fish and Wildlife Service.30 pp. http://ecos.fws.gov/docs/candidate/assessments/2014/r6/Q3B5_P01.pdf

US Fish and Wildlife Service, 2014. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus microcymbus. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus microcymbus : US Fish and Wildlife Service.53 pp. http://ecos.fws.gov/docs/candidate/assessments/2014/r6/Q06J_P01.pdf

US Fish and Wildlife Service, 2014. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Eriogonum soredium. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Eriogonum soredium : US Fish and Wildlife Service.24 pp. http://ecos.fws.gov/docs/candidate/assessments/2014/r6/Q2OT_P01.pdf

US Fish and Wildlife Service, 2014. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Lepidium ostleri. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Lepidium ostleri : US Fish and Wildlife Service.24 pp. http://ecos.fws.gov/docs/candidate/assessments/2014/r6/Q2UC_P01.pdf

US Fish and Wildlife Service, 2014. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Trifolium friscanum. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Trifolium friscanum : US Fish and Wildlife Service.23 pp. http://ecos.fws.gov/docs/candidate/assessments/2014/r6/Q3N5_P01.pdf

US Fish and Wildlife Service, 2014. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Urocitellus endemicus. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Urocitellus endemicus : US Fish and Wildlife Service.23 pp. http://ecos.fws.gov/docs/candidate/assessments/2014/r1/A0EO_V01.pdf

US Fish and Wildlife Service, 2015. U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus schmolliae. In: U.S. Fish and Wildlife Service species assessment and listing priority assignment form: Astragalus schmolliae : US Fish and Wildlife Service.29 pp. http://ecos.fws.gov/docs/candidate/assessments/2015/r6/Q07C_P01.pdf

USDA-ARS, 2003. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2002. The PLANTS Database, Version 3.5. National Plant Data Center, Baton Rouge, USA. http://plants.usda.gov

Wiggins IL, 1980. Flora of Baja California. Stanford, USA: Stanford University Press

Wilken DH, Painter EL, 1983. Bromus spp. In: Hickman JC, ed. The Jepson Manual. Berkeley, USA, University of California Press, 1239-1243

WSSA, 2003. 1,000 weeds of North America: an identification guide. Lawrence, USA: Weed Science Society of America

Yensen DL, 1981. The invasion of alien plants in southern Idaho. Great Basin Naturalist, 41:176-183

Young JA, 1988. The public response to the catastrophic spread of Russian Thistle (1880) and Halogeton (1945). Agricultural History, 62(2):122-130

Young JA, Blank RR, Burnside L, 1998. Reclamation of heap-leach mining spoils in arid environments. J. Arid Lands Studies 7:227-230

Young JA, Clements CD, 2002. Purshia: the wild and bitter rose., Reno, NV, USA. University of Nevada Press

Young JA, Evans RA, 1976. Responses of weed populations to human manipulations of the natural environment. Weed Science, 24(2):186-190

Young JA, Evans RA, 1982. Temperature profiles for germination of cool season range grasses. Agricultural Research Results, ARS, USDA, No.ARR-W-27:100pp

Young JA, Evans RA, Eckert RE, 1969. Population dynamics of downy brome. Weed Science 17:20-26

Young JA, Evans RA, Eckert RE, Kay BL, 1987. Cheatgrass. Rangelands, 9:266-270

Young JA, Evans RA, Lee WO, Swan DG, 1984. Weed brome grasses and their control. Farmer's Bulletin 2278. Washington DC, USA: USDA

Young JA, Evans RA, Major J, 1972. Alien plants in the Great Basin. Journal of Range Management, 25(3):194-201

Young JA, Longland WS, 1996. Impact of alien plants on Grant [Great] Basin rangelands. Weed Technology, 10(2):384-391; 50 ref

Young JA, McKenzie D, 1982. Rangeland drill. Rangelands, 4:108-113

Young JA, Sparks BA, 2002. Cattle in the cold desert. Logan, USA: Utah State University Press

Young JA, Tipton FH, 1990. Invasion of cheatgrass into arid environments of the Lahonton Basin. General Technical Report 276. Odgen, USA: USDA Forest Service, 37-40

Young JA, Trent JD, Blank RR, Palmquist DE, 1998. Nitrogen interactions with medusahead (Taeniatherum caput-medusae subsp. asperum) seedbanks. Weed Science, 46(2):191-195; 15 ref

Distribution Maps

Top of page
You can pan and zoom the map
Save map