Kochia weeds reach up to Jake Leguee’s waist on his family’s farm near Fillmore, Sask.
This year’s lentil and flax fields, about 100 kilometers southeast of Regina, have been choked by the invasive tumbleweed.
“A kochia plant can cause a lot of damage,” Leguee said. “That seed becomes thousands.”
Kochia has always thrived in drought conditions. Now, their resistance to herbicides is increasing and costing farmers.
“Every time we are in the field, we are spraying kochia,” Leguee said.
‘A major expense’
Leguee spends hundreds of thousands of dollars a year on herbicides and sprays hard-to-kill weeds several times a week.
In previous years, kochia could be killed using Group 14 herbicides, a product three times more expensive than older herbicides. Now, those can’t even eradicate weeds.
Last year, Leguee bought a $100,000 weed killer for his combine, hoping it would work.
“It’s a significant expense to add to a machine like that,” Leguee said. “It’s harder for smaller farms to adapt some of these tools and that’s a long-term concern.”
Despite these costly investments, Leguee has not managed to tame the beast.
Experts say that while kochia has been confined to the southern prairies for years, it is now spreading rapidly.
“A couple of years ago, I would always hear growers say, ‘We don’t have kochia; we’re not going to get it,'” said Shaun Sharpe, a scientist with Agriculture and Agri-Food Canada who specializes in invasive weeds. “And now the story is that we have it and it’s moving north.”
Sharpe said kochia has been detected in Saskatchewan as far north as Blaine Lake, about 80 kilometers north of Saskatoon, in the province’s northern grain belt.
In Alberta, the herb has been found in the Peace Country region in the northwest of the province.
It is moving north as a result of climate change and deforestation, Sharpe said.
“We have cut down many lines of trees, which would block the wind,” he said. “Now he has an open meadow that he can just circle around and fly around.”
Trying to stop the spread
Now, agri-food scientists like Sharpe are stepping up. His team is researching ways to clamp down on kochia, such as testing sister variants and providing education to farmers on how to identify the species on their land.
“It took me a while to learn to identify it,” Sharpe said. “These are producers who didn’t have to deal with that before.”
Scientists are also monitoring two other herbicide-resistant weeds, known as waterhemp and Palmer amaranth. Its seeds travel through grains, feed and through the animals themselves, since they are not something that their bodies can digest properly.
The plants are already present in Manitoba and North Dakota.
Sharpe estimates the weeds, known to be more difficult to eradicate than kochia, will infiltrate Saskatchewan in less than five years.
“Kochia is bad enough and many growers are fighting it,” Sharpe said. “Therefore, having a weed that has the same caliber of competition can be disastrous, especially for our progress towards crop diversification.”
Tyler Smith, a botanist with Agriculture and Agri-Food Canada in Ontario, told CBC that the lack of existing research makes it difficult to track invasive patterns.
“We have a lot of really good data on precipitation and temperature,” Smith said. “We don’t have a lot of data on how these plants interact, how weeds might interact with other things in the environment, what kind of soil requirements they might have.”
In southern Saskatchewan, the Leguee harvest is almost over. He hopes to get better results after a second year using the weed killer on his combine.
But Leguee said the spread of kochia is affecting food production, making it difficult to turn a profit.
“It’s a problem in our cereals,” Leguee said. “It can be a problem in our canola and every time we get a piece of kochia, there’s less yield there, there’s less production.”
“It could reduce our farm’s ability to make a profit, reduce our ability to continue doing this.”
