Weed Wisdom June 2020

Foxtail Barley (Hordeum jubatum L.)

By Nicole Vincent and Charles Geddes

In Alberta, foxtail barley steadily increased in abundance and frequency of occurrence in annual field crops (see figure). According to the 2017 Alberta Weed Survey, it is on the list of top 25 most abundant weeds in Alberta for the first time. This increase is attributed to zero tillage practices and a lack of effective herbicide options.

foxtail map

Foxtail barley (Hordeum jubatum L.) is a perennial species indigenous to western North America. It is most prevalent around sloughs, field edges, and areas that experience spring flooding or poor drainage. It is successful in these areas because it tolerates moderate salinity. Foxtail barley grows in clumps with shallow, fibrous roots and hollow stems 30 to 60 cm tall. The head has very long, dense awns that mature from greenish purple to yellow or white. It reproduces using seeds dispersed by wind or animals. Seeds are viable for three years and germinate at or near the soil surface.

Foxtail barley plant straw
Note the hollow looking stems spread on the ground. Credit: Farming Smarter

Foxtail barley can be a problem in pastures and rangelands. Although it is palatable to sheep, cattle, and horses, the awns can penetrate skin, mouth, nostrils and eyes causing injury and infection. It is also a problem in crops because it can host powdery mildew and various types of wheat rust. Foxtail barley competes well with winter cereals because it germinates in fall then steals moisture and nutrients in spring.

Tillage is the most effective control of foxtail barley. Even shallow tillage can destroy mature plants that are difficult to control with herbicide. Mowing is ineffective because the plant becomes more competitive and the seeds continue to mature on the stalk. In pasture, spring grazing or planting a competitive grass can control outbreaks. On cropland, planting a competitive crop, using a high seeding rate, and placing fertilizer in a band can reduce foxtail barley populations.

Field scouting is extremely important to ensure foxtail barley is at the appropriate stage, young or growing, for herbicide application. If conditions are suitable, a post-harvest glyphosate application can control foxtail barley because it gives the best root kill of mature plants and controls fall germinated seedlings. An early pre-plant glyphosate application is also effective in controlling overwintered seedlings. Herbicide intended for grassy weeds in oilseed and pulse crops can be mildly effective in killing seedlings and suppressing mature plants. In-crop herbicides for cereals are often ineffective due to lack of selective herbicide options and because foxtail barley is often at later growth stages by the time of post-emergence herbicide application.

Mature foxtail barley
Mature foxtail barley Credit: Farming Smarter

Because foxtail barley can be difficult to control once it is established in pasture or cropland, prevention is the best way to minimize its impact. Improving drainage and controlling water levels in wet areas can minimize soil salinity and improve competition of other species. Applying herbicide in non-crop areas with dense foxtail barley populations can also help mitigate its spread into the crop. Often prevention is combined with cultural, mechanical, and chemical control to reduce foxtail barley populations in arable fields.

References

Best, K.F., Banting, J.D., and Bowes, G.G. 1978. The biology of Canadian weeds. 31. Hordeum jubatum L. Can. J. Plant Sci. 58: 699-708.

Leeson, J.Y., Hall, L.M., Neeser, C., Tideman, B., and Harker, K.N. 2017. Alberta weed survey of annual crops. Weed Survey Series Publ. 19-1. Agriculture and Agri-Food Canada, Saskatoon, SK. 275 p.

Government of Alberta. 2007. Foxtail barley control in direct seeding systems. [Online]. Available: [25 Mar. 2020].