Fall weed control

Alberta Agriculture and Rural Development

There is a window of opportunity this year for fall weed control. “It doesn’t work out every year that we have this opportunity, but this year it does,” says Harry Brook, crop specialist, Alberta Ag-Info Centre, Stettler. “There can’t have been a terrific killing frost, the plants have to be actively growing, there has to be some green leaf material that will absorb the chemicals.”

Brook says conditions like this allow for much better weed control now than in the spring.

“If you have plants that are green, and you’ve got some moisture in the soil, this is the time to hit the weeds with a herbicide. The annual weeds can be taken out with a simple application of a phenoxy herbicide like 2,4-D or MCPA, but this is the time that glyphosate really shines.”

As far as winter annual weeds are concerned, says Brook, they’ll start germinating now if there are good growing conditions. “They are easy to kill now, but if you wait until next spring, they can shoot up and flower before you have a chance to control them.”

If producers try to do fall weed control after harvest, the difficulty is having a long enough window for the plants to grow and take up the chemical. “You might also have too much trash on the surface which can interfere with the chemical coming into contact with the problem weeds.”

For more information on fall weed control, call the Ag-Info Centre at 310-FARM (310-3276).