GFM Network News


Green foxtail can cut wheat yields by a quarter when populations reach 400 to 500 plants per square metre.

A large weed seed bank is a ‘gift that keeps taking’

No till, chaff collection, forage in rotation, and chemical control all reduce weed pressure

Below the soil surface lurks the weed seed bank — the predominant source of weed pressure on current and future crops. “You do not want to draw on this bank account,” said provincial crop specialist Harry Brook. “It is a source of annual and perennial weeds that will wait for years before the right conditions […] Read more

These Manitoba Department of Agriculture photos show that weeds are more obvious when looking 
down at a wheat crop (r) than looking at it sideways.

It’s the time of year when crop scouting pays big dividends

Weed escapes, herbicide resistance, disease, and pests can all be assessed after spraying, says expert

Spray, then scout, says provincial crop specialist Mark Cutts. “It is very important to recognize that scouting after a herbicide application is vital to weed control, said Cutts. “In the majority of cases, producers will find that the chemicals have worked. However, in certain situations, field scouting may show the weeds weren’t properly controlled. Producers […] Read more


Understanding how plants search out nutrients, and react to weeds and pests could have a huge impact on farming in the coming decades, says biologist JC Cahill.

Listen to your crops — the plants are talking to each other

They’re also ‘foraging’ for nutrients, deciding where to put their roots, and calling for help when under attack

You might think it’s crazy — but plants talk to each other and act in ways that are similar to animals and humans. “Step away from the idea of plants as factories and start to think of plants as individuals,” biological sciences professor JC Cahill told attendees at the Western Canadian Soil Health and Grazing […] Read more

Perennial sow-thistle.

Perennial sow thistle costs farmers across Alberta

Noxious Weeds: Perennial sow thistle causes yield loss and acts as a host for pests

Often found in high densities across Alberta, perennial sow thistle seems to be a noxious weed that doesn’t quit. Not only does this pest cause significant yield loss in many crops, but it’s a host for several plant pests that attack economically important crops such as alfalfa, winter wheat and canola — just to name […] Read more


Scouting for weed escapes after spraying allows you to assess both the effectiveness of the application and spot an emerging resistance issue.

Timely and effective field scouting covers many bases

Provincial crops specialist says scouting not 
only pays dividends this year, but allows you to fine-tune practices for future years

Plant density, weed escapes, early signs of disease, and pest populations should all be on your scouting checklist, says a provincial crop specialist. Evaluating the plant population for a given crop lets producers see if the number of plants (per square foot or square metre) matched the target goal that was established at the time […] Read more



Wild oats is currently resistant to the most number of herbicide groups of any weed.

‘Wake-up call’ needed for resistance

Provincial crop expert says it’s time to stop pretending it’s not ‘a huge issue’

Weed resistance has been an issue in crop production for many years, but is coming to the forefront as increasing numbers of weeds are no longer responding to herbicides. “Most producers are aware of the issue, but unless it affects them directly, don’t see it as a huge issue,” said provincial crop specialist Harry Brook. […] Read more

Assessing the threat from a weed starts with identifying it. For example, whitlow grass (left) isn’t a big threat, but scentless chamomile (right) is, says provincial crop specialist Harry Brook. photos: wiki commons

Know your enemy and its destructive potential, says provincial crop specialist

There’s a critical window for controlling weeds, but it depends on both the crop 
and the threat posed by individual species

All crops have a critical weed control period when they are most susceptible to significant yield loss from weed competition. The critical weed control period for canola is around 17 to 38 days after emergence. Peas can be as early as two weeks after emergence. “Other, more competitive crops, like the cereals, have a less […] Read more


Seed from Canada thistle can germinate eight to 10 days after flowering, but roots — not seeds — are the main way that this noxious weed spreads.

This quick-spreading weed gets an early start

Noxious weeds: Canada thistle

Spring brings lovely native flowers, but also noxious weeds. The aggressive perennial Canada thistle is a favourite of disturbed soils of all types. It starts sending shoots from horizontal roots to the surface of soil around mid-April, with flowers to follow in mid-June and continuing throughout the summer. Easy to distinguish from other weeds, this […] Read more

The flower of field scabious is pretty but the weed can invade hayfields and other grassy areas and be widely dispersed via baled forage.

Don’t be fooled by this weed’s pretty flower

Noxious weeds: Field scabious

Field scabious was introduced as an ornamental from Europe and is now taking over roadsides and pastures. It can be found throughout central Alberta and has the ability to invade even undisturbed plant communities, such as hayfields. Once established it is very difficult to control. Flowers can be a purple- to blue-coloured clustered head, resembling […] Read more