HPIPM:Jointed goatgrass

Taxonomy

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

Scientific Name

Aegilops cylindrica

Scientific Name Synonyms

Triticum cylindricum

Cylindropyrum cylindricum

Aegilops cylindrica rubiginosa

Common Name

jointed goatgrass

Jointed goatgrass(Aegilops cylindrica)

Author: Drew Lyon, University of Nebraska Lincoln

Identification and Life Cycle

Jointed goatgrass (Aegilops cylindrica) is an introduced annual grass (Poaceae). Jointed goatgrass and winter wheat (Triticum aestivum) are genetically related. Thus, jointed goatgrass is similar in appearance to winter wheat during the early vegetative growth stages but can be distinguished from winter wheat by the occasional hairs extending from the margin of the leaf blade, particularly near the collar. The spike (seed head) is a narrow cylinder composed of spikelets that contain two to four flowers. The glumes on the uppermost spikelets are long-awned. Each spikelet contains an average of two seeds. A spikelet or joint is attached to the root of emerging seedlings, which provides another method of distinguishing between jointed goatgrass and winter wheat.

Habitats

Jointed goatgrass is found mostly in wheat fields but can also occur along roadsides, in waste areas, alfalfa fields, and pastures.

Impacts

During winter wheat harvesting, jointed goatgrass spikelets can shatter and contaminate harvested winter wheat grains. Jointed goatgrass can reduce winter wheat yields by competing for moisture, light, space, and nutrients.

Biology and Ecology

Jointed goatgrass emerges from September through early November and again in late winter and early spring. Flowering and seed production can occur from May to July. Seeds develop rapidly after pollination. Plants reproduce from seed, and individual plants can produce as many as 3,000 seeds per plant. Seeds can remain viable in the soil for at least four years. Jointed goatgrass and winter wheat have very similar life cycles and occasionally cross to produce a hybrid that is intermediate in form. Seeds from these hybrids are typically sterile.

Biological Control

Although biological control of jointed goatgrass with bacterial pathogens has shown limited success in the laboratory, little success has been observed in the field.

Mechanical and Cultural Control

Winter wheat rotations containing a late spring-planted crop such as proso millet or sunflower plus fallow have provided 99% jointed goatgrass control. Mowing between the flowering and soft dough stages can be effective. If done too early, however, new tillers will form and produce viable seeds. Rough ground and the presence of prostrate jointed goatgrass plants may limit mowing effectiveness.

Chemical Control

Due to the genetic similarity between jointed goatgrass and winter wheat, selective chemical control is only available using the Clearfield® wheat system, which involves the use of imazamox-resistant wheat cultivars. Several nonselective herbicides will control jointed goatgrass in fallow.

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 jointed goatgrass

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
pronamide	Group 3: Inhibitors of microtubule assembly
*Kerb 50-W		1 - 4 pounds	Applications may be made postemergence to established, actively growing or dormant forage legumes or to new plantings after the legume has reached the trifoliate leaf stage. In established forage legume stands, applications should be made after the last cutting when the weather and soil temperatures are cool.
Clearfield® Wheat
Imazamox	Group 2: Inhibitors of acetolactate synthase (ALS)
*Beyond		4 ounces	Apply after tiller initiation and before jointing to Clearfield® wheat cultivars only.
Small grains
Glyphosate	Group 9: Inhibitor of EPSP synthase
*Roundup Original Max		16 ounces	Apply to actively growing weeds in the spring or fall, before planting or emergence of the crop. Also may be applied prior to harvest or after harvest.
Fallow
Glyphosate	Group 9: Inhibitor of EPSP synthase
*Roundup Original Max		16 ounces	Apply to fallow only when goatgrass is 6 inches or less in height.
*Helosate Plus		16 ounces	Apply to fallow only when goatgrass is 6 inches or less in height.

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=jointed%20goatgrass

For more information on jointed goatgrass please see University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources publication G1252: Controlling Jointed Goatgrass. http://www.ianrpubs.unl.edu/epublic/live/g1252/build/g1252.pdf