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Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Lilianae
Order	Poales
Family	Poaceae
Subfamily	Pooideae
Tribe	Bromeae
Genus	Bromus

Scientific Name

Bromus tectorum

Scientific Name Synonyms

Anisantha tectorum

Bromus tectorum var. glabratus

Common Name

cheatgrass, downy brome

Cheatgrass or Downy brome (Bromus tectorum L.)

Author: Drew Lyon, University of Nebraska Lincoln

Identification and Life Cycle

Cheatgrass (Bromus tectorum L.), also called downy brome is a winter annual grass weed (family Poaceae). Plants grow from 6 to 24 inches tall. Height depends on available soil moisture, fertility, and competition. Leaf blades are flat, approximately 1/32 inch wide and 2 – 6 inches long. Both the blades and sheath are hairy. Leaves are a brownish green in color and turn purplish-tan as seeds reach maturity. Roots are fibrous and relatively shallow. Stems are slender and erect and protrude from a highly branched base. Panicles are 2 – 6 inches long, slender, and drooping to one side. Downy brome has numerous spikelets with 5-8 flowers and strait awns, 1/2 to 3/4 inch long. Downy brome has a shallow root system and roots with many root hairs which enable the plants to extract much soil water.

Habitats

Downy brome thrives in all soil types. Downy brome grows in croplands and is particularly troublesome in alfalfa, winter wheat-fallow rotations, and continuous wheat systems. Downy brome also invades rangelands, waste areas, roadsides, shelterbelts, fencerows, and railroad rights of way.

Impacts

Downy brome infestations can reduce wheat and alfalfa yields, and reduces alfalfa quality. Downy brome also effectively competes for soil water in croplands and rangelands. Overgrazed rangelands are more easily invaded by down brome which reduces economic returns of grasslands. Downy brome is a palatable grass before the seed heads emerge, but becomes unpalatable with maturity. Mature downy brome can cause injury to livestock by causing infection in the eyes or mouth. Mature plants are also a serious fire hazard.

Biology and Ecology

Downy brome usually begins growth in fall or early spring. Reproduction is by seed. Downy brome may produce many tillers depending on germination time. Plants that begin growth in the fall continue to tiller and set seed in the early spring. Seeds are light and fluffy and initial seed germination rates can be high. Heavy infestations can produce 80,000,000 seeds per acre. Seeds may remain viable for up to 2 years.

Management Approaches

Downy brome can be controlled using an integrated program by managing non-crop areas to reduce seed sources, crop rotation, and chemical control.

Biological Control

There is currently no biological control program for downy brome.

Mechanical and Cultural Control

Tilling and cropping roadside ditches or seeding them to perennial grasses can help eliminate seeds sources. Waste areas and field margins can be seeded with cool-season grasses such as crested wheatgrass or smooth brome. Vigorous stands of grasses or grass-legume combinations are highly competitive with downy brome. Mowing can be used to reduce seed production, but will not eliminate downy brome. Crop rotation is the most effective control method. Crops planted in late spring are much more effective than crops planted in early spring. With late spring planted crops, tillage and/or herbicides can be used to control downy brome before planting. Crop rotations with two years of late spring planted crops provide almost 100% downy brome control if plants are kept from producing seeds during the fallow periods.

Chemical Control

There have been reports of ALS inhibitor resistance in downy brome in Oregon. For more information on herbicide resistance in downy brome please see http://www.weedscience.org/Summary/USpeciesCountry.asp?lstWeedID=40&FmCommonName=Go .

For herbicide recommendations for specific grain rotations and weeds in Montana, please see the MSU Herbicide Chooser Tool.

Examples of herbicides that can be used to manage downy brome

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Herbicide Active Ingredient trade name	Mode of Action	Product per Acre	Application Time or Growth Stage
Alfalfa
Clethodim	Group 1: Inhibitors of acetyl CoA carboxylase (ACCase)
*Select Max		9 - 16 ounces	Apply when grasses are 2-6 inches tall
Imazamox	Group 2: Inhibitors of acetolacetate synthase (ALS)
*Raptor		4 - 6 ounces	Apply before downy brome reaches 3 inches in height
Clearfield® Wheat
Imazamox	Group 2: Inhibitors of acetolacetate synthase (ALS)
*Beyond		4 ounces	In Clearfield® wheat from 3-leaf to jointing, when downy brome has 1-5 leaves and no more than 2 tillers.
Winter Wheat
Propoxycarbazone	Group 2: Inhibitors of acetolacetate synthase (ALS)
*Olympus		0.9 ounce	From wheat emergence to jointing.
Sulfosulfuron	Group 2: Inhibitors of acetolacetate synthase (ALS)
*Maverick		2/3 ounce	From wheat emergence to jointing.
Pyroxsulam	Group 2: Inhibitors of acetolacetate synthase (ALS)
*PowerFlex		3.5 ounces	From 3-leaf wheat to jointing.
Fallow
Glyphosate	Group 9: Inhibitor of EPSP synthase
*Roundup Original Max		16 ounces	Apply before downy brome reaches 6 inches in height
Peas and Lentils
Imazamox	Group 2: Inhibitors of acetolacetate synthase (ALS)
*Raptor		4 ounces	Apply before downy brome reaches 3 inches in height
Rangeland
Sulfometuron	Group 2: Inhibitors of acetolacetate synthase (ALS)
*Campaign		45 - 54 ounces	Apply when most mature brome plants are in flower and before plants and seed heads turn color

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=downy%20brome&Start=1&results=56

For more information on downy brome please see University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources publication G422: Downy Brome Control. http://www.ianrpubs.unl.edu/epublic/live/g422/build/g422.pdf

or see Invasipedia for more detail on downy brome: http://wiki.bugwood.org/Bromus_tectorum

HPIPM:Cheatgrass