Prairie farmers worried about food production as invasive weeds spread

Kochia weed is as tall as Jake Leguie’s waist on his family farm near Fillmore, Sask.

This year, lentil and flax fields about 100 kilometers southeast of Regina have been choked by invasive tumbleweed.

“One kochia plant can do a lot of damage,” Leguay said. “That one seed turns into thousands.”

Kochia has always thrived in drought conditions. Now, its resistance to herbicides is increasing, and farmers are paying the price.

“Every time we’re in the field, we’re spraying for kochia,” Legui said.

‘A significant expense’

LeGue spends hundreds of thousands of dollars on herbicides each year, spraying hard-to-kill weeds several times a week.

In years past, kochia could be killed using a Group 14 herbicide, a product three times more expensive than the older herbicides. Now, they can’t even weed.

Last year, Legui bought a $100,000 weed killer add-on to his combine, hoping it would work.

“It’s a significant expense to add to a machine like this,” Leguay said. “It is difficult for small farms to adopt some of these tools and that is a long-term concern.”

Despite these costly investments, Legui has failed to tame the beast.

Experts say kochia has been confined to the southern plains for years, but is now spreading rapidly.

“A few years ago, I would always hear growers saying, ‘We don’t have kochia; we’re not going to get it,'” said Shawn Sharp, a scientist with Agriculture and Agri-Food Canada who specializes in invasive weeds. “And now the story is that we’ve found it and it’s moving north.”

Sharp said kochia has been found north of Blaine Lake in Saskatchewan, in the province’s northern grain region, about 80 kilometers north of Saskatoon.

In Alberta, this weed has been found in the Peace Country region in the northwest of the province.

It’s moving north as a result of climate change and deforestation, Sharp said.

“We have cut down a lot of trees, which will block the wind,” he said. “Now, it has a wide open area, it can just fall and fly.”

Efforts are being made to stop the spread

Now, agri-food scientists like Sharp are stepping forward. His team is researching ways to crack down on Kochia, such as running trials on companion variants and providing education to farmers about identifying the species on their land.

“It took a while to learn how to recognize it,” Sharp said. “These are growers who didn’t have to deal with this before.”

Scientists are also monitoring two other herbicide-resistant weeds, known as waterhemp and Palmer amaranth. Their seeds travel through grains, animal feed, and the animals themselves, as they are not something their bodies can digest properly.

These plants are already present in Manitoba and North Dakota.

Sharp estimates that the weed, which is considered more difficult to eradicate than kochia, will invade Saskatchewan in less than five years.

“Kochia is pretty bad anyway and a lot of growers struggle with it,” Sharp said. “So the arrival of a weed with similar ability to compete could be devastating, especially for our progress in crop diversification.”

Tyler Smith, a botanist with Agriculture and Agri-Food Canada in Ontario, told CBC that the lack of existing research is making it difficult to track invasive patterns.

“We’ve got a lot of good data for precipitation and temperature,” Smith said. “We don’t have a lot of data on how these plants might be interacting, how the weeds might be interacting with other things in the environment, what kind of soil requirements they might have.”

In southern Saskatchewan, the legui crop is almost gone. He’s expecting better results after using the weed terminator on his combine for the second year.

But Leguay said the spread of kochia is affecting food production, making it difficult to turn a profit.

“It’s a problem in our grains,” Leguay said. “It can be a problem in our canola and every time we get a patch of kochia, there’s less yield, there’s less production.”

“It could reduce our farm’s ability to make a profit, reduce our ability to continue.”