Jointed Goatgrass
Aegilops cylindrica
Key Characteristics
Annual grass
- 15-30 inches tall
This information courtesy of the Colorado Natural Areas Program
Family: Poaceae (Grass)
Other Names: goatgrass
USDA Code: AECY
Legal Status: Colorado Noxious Weed List B
Identification
Lifecycle: Annual
Growth form: grass
Flower: The seed head is 2-4 inches long with 5-10 spikelets (joints) per head. Early to mid-June.
Seeds/Fruit: Spikelets are 0.5 inches long with 1-3 viable seeds. At maturity spikelets separate with a segment of the stems still attached
Leaves: Leaves are alternate, simple, with a flap-like appendage (auricle) at the base, and a leaf blade 0.17-0.25 in wide, with hairs
Stems: Mature plants are generally 15-30 in tall with one to many tillers.
Roots: Short fibrous root system
Similar Species
Exotics: Similar in appearance, and genetically related to, winter wheat
Natives: N/A
Impacts
Agricultural: Jointed goatgrass has become a very serious weed in winter wheat and other cereal crops. Its genetic similarity, and similar growth characteristics to winter wheat make it very difficult to control without adversely harming crop production. Jointed goatgrass also infests rangeland surrounding wheat growing areas and land in the Conservation Reserve Program throughout the western United States.
Habitat and Distribution
General requirements: It can flourish in areas of less than 10 to more than 20 inches annual rainfall
Distribution: Jointed goatgrass is found throughout the western United States at elevations up to 6,000 feet
Historical: Jointed goatgrass is thought to have been introduced from Turkey in contaminated wheat
Biology/ Ecology
Life cycle: Jointed goatgrass flowers in early to mid-June. Some jointed goatgrass seeds germinate early and the remainder of the seeds may persist in the soil for years. Jointed goatgrass seeds usually germinate from early August through October but they can also germinate in late spring and still mature if temperatures are low enough
Mode of reproduction: Seed
Seed production: A jointed goatgrass plant can produce up to 100 spikes, 1,500 spikelets and up to 3,000 seeds
Seed bank: Soil moisture plays an important role in jointed goatgrass seed viability and dormancy. Regardless of conditions, jointed goatgrass seeds rarely remained viable for over five years in the soil.
Integrated Management Summary
Studies have shown that jointed goatgrass, winter wheat, and downy brome all compete for nutrients, moisture, and light. Comparatively, winter wheat is usually more competitive than jointed goatgrass, and both are much more competitive than downy brome. Jointed goatgrass also has a faster growth rate than downy brome. This faster growth rate, plus the use of herbicides that are more effective controlling downy brome than jointed goatgrass, may result in a weed species shift from downy brome to jointed goatgrass. An integrated management strategy should focus on preventing the establishment of new infestations in suceptible areas, and depleting the soil seed bank.
Control
Biocontrol: None known
Mowing can be an effective control method if it is correctly timed. Mow soon after jointed goatgrass flowers, but before the seeds mature.
Fire: Post harvest burning of winter wheat stubble in Washington reduced germination of jointed goatgrass seed lying on the soil surface by up to 90%. In order to be effective, peak soil surface temperatures must reach 200°F or more for up to 60 seconds. Spring burning of fallow or non-crop land will effectively kill jointed goatgrass and other winter annual weeds growing at the time, but will usually not destroy seeds on or in the soil.
Herbicides: Because jointed goatgrass and wheat are genetically related, no currently registered herbicides will selectively control jointed goatgrass in winter wheat. Fallow is one of the best times to control jointed goatgrass because selectivity is not important. Jointed goatgrass is usually controlled best when plants are less than 4 inches tall, in the tiller stage, and non-stressed.
Cultural/Preventive: Where jointed goatgrass is concerned “an ounce of prevention is worth a pound of cure.” The key to control is to prevent further increase of jointed goatgrass seed in the soil seed bank and to optimize conditions that hasten depletion of viable seed in soil. Seeds are difficult to distinguish from wheat, and are often spread by being planted with wheat or by uncleaned combines. Spread can be minimized by sowing jointed goatgrass-free seed wheat, covering trucks transporting contaminated grain, thoroughly cleaning machinery before moving from infested to non-infested areas, processing contaminated grain before feeding to livestock, and not baling or transporting contaminated straw to non-infested areas.
References
Lyon, D.J. 1998. Jointed Goatgrass Biology. Internet 07/28/98. www.ianr.unl.edu/jgg/billings/lyonbiol.htm
Morishita, D.W. 1998. Biology of Jointed Goatgrass. Internet 07/28/98. www.ianr.unl.edu/jgg/conf/morish2.htm
Stahlman, P.W. 1998. Jointed Goatgrass Control Methods – A Review. Internet 11/12/98. www.ianr.unl.edu/jgg/stahlman.htm
Whitson, T.D.(ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 1996. Jointed goatgrass. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA . pg. 408.
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