Foxtail barley problem on the rise on Prairies

Difficult growing conditions in many areas of Western Canada have made some crops less competitive, providing an opening for weeds like foxtail barley to gain a foothold.

“We’re seeing a fair amount more of foxtail barley in Manitoba and I imagine it’s the same for a lot of Western Canada. We’re seeing more of it because it’s taking advantage of conditions where the crop has had a hard time,” says Bruce Murray, a weed specialist with Manitoba Agriculture.

“We’ve had salinity increasing somewhat, drought a few years ago, flooding and excessive wet conditions. Add in BSE, where pastures were carrying more stock and getting overgrazed. All those conditions have led to openings for foxtail barley and it’s increased over time.”

Foxtail barley is expanding into both pastures and cropland. Murray said the switch to direct seeding has helped the weed.

“Tillage is a wonderful option for the control of foxtail barley. Without tillage as a regular tool, we’re finding it more and more on cropland. The location of foxtail barley patches depends on how competitive the crop is. If you’ve got a good healthy crop, it doesn’t have much of a chance to get going,” he said.

“Fields last year had a lot of land under standing water or excessively wet. That’s an opening for it. Quite often you do see it around ditches, sloughs and lower areas, because of salinity. It just depends on conditions throughout the field.”

The weed is a short-lived perennial that spreads by seed. Murray said it grows under a variety of environmental conditions, but it can do well under extreme environments in the absence of competition.

“Foxtail barley is often found in saline areas and will do well under drought conditions. The 2003 drought is likely why we are seeing more of this weed in cropped land. Pastures have been put under extreme stress with higher grazing pressures and previous dry conditions. Drought and salinity both create an opening for foxtail barley to establish and flourish,” he said.

Murray said foxtail barley is not a serious problem under conventional tillage systems. Seed survival is poor when buried deeper than 7.5 centimetres for more than a year.

Established foxtail barley plants are shallow rooted so tillage works well to control them. Cultivation of established plants is successful if the operation is aggressive enough to uproot the crown. Plowing or discing is preferred for controlling both seeds and established plants.

Repeated mowing, similar to intensive grazing, may serve to delay and reduce seed set, but mowing alone will not fully control foxtail barley populations over the long term.

“It’s a bit of a wimp to start with, but once it gets an opening and gets established, it takes advantage of it.”

While not resistant to chemicals, Murray said foxtail barley can at times be difficult to control with a standard glyphosate burnoff.

“There’s two creatures you’re trying to control. The first one would be the seedlings and they’re relatively easy to control. Half a litre of glyphosate pre-seed or in the fall does a pretty good job on it.

“The established clump perennial is a tougher creature to kill. … The awns, leaves and stems are hairy, so water and droplets can roll off fairly easily. It might be as much a mechanical thing, with water droplet adhesion.”

Murray said the herbicide Kerb 50-WSP is an option in pastureland, but it’s not used a lot.

“It’s relatively expensive and it’s an odd timing, from October to freezeup. And it’s aimed at pastureland and a lot of guys aren’t spending money to renovate a pasture or remove weeds from a pasture. Quite often it’s just as easy to rip a pasture up and reseed it.”

Kerb controls weeds via root uptake, inhibits root growth and interferes with shoot development. But Murray said a number of restrictions and conditions apply to this product.

  • Kerb should only be applied to cold soils. Oct. 1 to freezeup is the best time for pastures. Kerb is sensitive to degradation and breakdown will occur rapidly in warm soils.
  • Kerb is to be applied to established pastures only.
  • Do not apply it to land that you intend to seed within a year (any crop).
  • Do not apply it to soils with more than six percent organic matter.
  • Pastures treated with Kerb may not be grazed for 60 days at the low rate, or 90 days at the high rate.
  • Kerb requires at least 7.5 cm of total moisture (rain, snow, irrigation) for adequate activation.

Murray said not all grasses have the same tolerance to Kerb. (See table.)

“You have some that are very tolerant, some that are OK and some that are very susceptible. So you’d better know your species, too.”

Other products that have registrations for foxtail barley, besides the glyphosate spring and fall applications, include Sundance for control and Poast Ultra for suppression.

Murray said many graminicides registered for use in cereals and broad-leafed crops will have some effect on foxtail barley, but most are not registered for use on this weed. All of these products are more effective on seedlings at the one- to four-leaf stage than tillering or established foxtail barley plants.

Foxtail barley can be grazed in the early spring with fair palatability. But when the plants enter the reproductive stage of growth and seed heads are formed, the barbed awns cause problems for grazing animals. The awns lodge in their mouths, eyes and noses and can cause serious injury. Livestock will avoid mature foxtail barley plants if given a choice.

The weed is not a highly competitive plant, but if allowed to establish via poor management or environmental conditions like salinity, drought or flooding, it can spread and take over in two to four years. Burning or early intensive grazing have had limited success.

Management practices that establish and maintain healthy vigorous crop or forage stands are the best defence against this weed.

Proper maintenance of saline, dry and flooded areas of a field or pasture through planting suitable species and adequate fertilization will help eliminate foxtail barley.

Murray said farmers tilling around sloughs might want to think twice before starting.

“The caution I have is, you’ve got to look at why is it there. Was it a drought, a flood or are you dealing with salinity? Tillage and salinity is not a good thing,” he said.

“You’re maybe having an impact on the weed, but you’re also creating better conditions for that weed to take advantage. You’ve got to look long term with this weed. It’s going to take a few years to bring it down and maybe you have to establish a competitive crop like a salt-tolerant forage. Get conditions so you’ve got good crop competition and it’s hard on that weed.”

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