HPIPM:Japanese brome

Japanese brome (Bromus japonicus Thunb.)

Compiled by Jane Mangold, Montana State University

and Marjolein Schat, Montana State University from the following sources:

http://plants.usda.gov/java/profile?symbol=BRAR5

http://www.agdepartment.com/noxiousweeds/pdf/Japanesebrome.pdf

http://alfalfa.okstate.edu/weeds/annbrome/jbrome.htm

http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=145897

http://www.oznet.k-state.edu/weedmanagement/Dallas%20Files/WH200204%20FD.pdf

Howard, Janet L. 1994. Bromus japonicus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/plants/graminoid/brojap/all.html [2008, October]

Identification and Life Cycle

Japanese brome (Bromus japonicas Thunb.) is also known as field brome (Bromus arvensis) and is an annual in the grass family (Poaceae). Japanese brome is a cool season, annual grass that can range in height from 14 to 40 inches. Leaf blades are flat, covered with soft, distinct, thin hair, approximately 1 to 8 inches in length, and 1/32 to 1/16 of an inch wide. Sheaths are covered with dense, soft hairs. Ligules are 1/64 to 1/16 of an inch long and auricles are absent. Inflorescence is an open panicle, 2 to 7 inches long with spreading, usually drooping branches. Spikelets are 6 to 10 flowered, 1/2 to 1 inch in length, and 1/8 to 1/4 of an inch wide. First glumes are usually 3- to 5- nerved, 1/8 to 1/4 of an inch long. Second glumes are 5- to 9-nerved and 1/4 to 1/2 of an inch in length. Lemmas are broader at the upper-half, tapering to the bottom, with margins not strongly enrolled in the fruit. Awns are 1/4 inch to 3/4 inch long, somewhat twisted and widely spread at maturity.

Habitats

The plant occurs on a wide variety of soils that include sand, silt, and clay, but thrives on fine-textured soils. Waste areas, disturbed sites, roadsides, pastures, rangelands, and wheat fields are areas where Japanese brome can establish. The plant is a common component of many mixed prairie communities.

Impacts

Japanese brome is an aggressive species that out-competes desirable vegetation for water and soil nutrients, thus reducing plant biodiversity. Forage production of perennial grasses and grazing performance is also reduced in Japanese brome infested areas.

Biology and Ecology

Japanese brome is an annual or winter annual that reproduces solely through seed production. Seedlings generally germinate in the fall, with a minority of seeds germinating in the spring. Following germination, each plant overwinters as a “rosette” of leaves. Flower buds emerge in early April, at which time the plants begin to bolt. Flowering occurs in early May and seeds ripen by late June or early July. Japanese brome senesces as the seeds mature and no living plants are observed in the summer. Seeds are retained on dead erect plants and are dispersed from October until March. Seeds may remain viable for several years.

Management Approaches

Management objectives for Japanese brome control should involve prevention, early detection and reducing or preventing seed production. Seeds of Japanese brome can remain viable in the soil for several years, therefore infestations should be monitored for several consecutive growing seasons to prevent germination of new plants.

Biological Control

No insect biological control agents are currently available for the control of Japanese brome.

Mechanical and Cultural Control

Prescribed burns can be effective for control of Japanese brome but may be dependent on the growing season and precipitation. Prescribed burning should be repeated sometime within 5 years after the first burn to continue to reduce litter accumulations, potentially reducing Japanese brome populations, especially when precipitation is low in the fall. Cutting or mowing may also be effective if conducted while the flowering head is still enclosed within the sheath of the plant. However, Japanese brome populations may increase after implementing these mechanical control methods. The disturbance associated with mechanical control methods may also favor Japanese brome growth. The plant is palatable and can provide fair to good forage for livestock during the fall and in the early spring prior to emergence of inflorescence. Grazing as a control measure has had variable results. Some authors suggest that Japanese brome may increase with moderate to heavy grazing.

Chemical Control

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

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.