Leafy spurge poses environmental threat

Cattle aren’t fond of the plant and eat only three percent, costing producers millions in lower livestock grazing capacity

ELBOW, Sask. ­— It’s not easy grabbing the public’s attention when trying to control a noxious weed such as leafy spurge.

“’Eradicate leafy spurge’ is not as attractive as ‘save the pandas,’ ” says Kerry Lowndes, an agri-environmental group plan technician with South Saskatchewan River Watershed Stewards Inc.

Lowndes, who helped organize a June 6 tour of a community pasture near Elbow, said the invasive species needs to be brought to the public’s attention because there will be repercussions if left unattended.

A Brandon University study found that a 40 percent infestation decreases carrying capacity of cattle by 50 percent.

The Elbow pasture is 27,000 acres and has an estimated 12,000 acres of leafy spurge of varying infestations.

That’s up from 2,000 acres in 1998, when Ross Sigfusson started working as pasture manager for the area.

Sigfusson has developed an integrated weed control process for controlling the infestation that attacks leafy spurge with everything it can.

For example, the program uses bio-control options such as brown and black dot beetles, which were introduced a few years ago.

“The brown dot likes it more hot and open, and the black dot would go into more densely bushy area, the thicker spurge patches,” he said.

“I think the long haul with the beetles is probably the answer, but it takes 30 years before you see any real changes.”

Herbicides are used on leafy spurge, but Sigfusson spot treats where possible rather than open spraying because of the high water table.

Grazing is another integrated control process. The Elbow pasture has brought in more than 1,600 goats and sheep to eat the noxious weed.

“I think that’s the way to go is to get producers who will bring in big numbers of sheep and take care of them themselves,” Sigfusson said.

“That way the herd health is maintained really well and everything is done good.”

Nadia Mori, a regional forage specialist from Watrous, Sask., who served as a tour guide, agreed that multiple strategies will be necessary to get the weed under control.

“If you hit densities that are 80 stems per sq. metre, your cattle are not even going to go through those patches anymore, and cattle will only eat three percent … versus sheep that can take 50 to 70 percent of their diet versus goats that can take 80 to 90 percent of their diet and be fine,” she said.

Manitoba Agriculture did two economic impact studies approximately 10 years apart after the invasive weed arrived in the province. The latest study concluded that the higher the infestation, the greater the loss.

Manitoba has more than 1.2 million acres of leafy spurge, which is costing the province more than $40.2 million a year, based on the direct and indirect losses from reduced livestock grazing capacity.

The province is now reviewing public policy and programming to find solutions.

Michel Tremblay, a grassland ecologist with Saskatchewan Parks, has seen the weed spread across the province.

“I’ve seen some spurge maps the parks put together 15 to 20 years ago, and I pine for those days,” he said. “Those problems were not fixed, and now we’ve got major problems.”

Tremblay said the best way to control leafy spurge is to attack it as soon as it is found before it gets out of hand.

“We put a spurge control strategy for the parks (together), and our goal is in five years reduce our leafy spurge area by 75 percent.”

The invasive species was discovered entering the United States in 1827, presumably from Europe, and has since aggressively spread across the northern U.S. and the Canadian Prairies.

“Each individual flower produces around 140 seeds, and it doesn’t just open and release the seeds — it has a capsule that bursts open and spits out the seeds up to 16 feet away,” Mori said.

Leafy spurge has a tremendous root system that can extend to nine metres deep and 4.5 metres radially.

“If you just leave a fragment of the root behind, it’s going to be able to regenerate from that,” Mori said.

“It’s made to take over areas and dominate areas, and that’s what it will do.”

Lorne Scott, co-chair of the Public Pastures – Public Interest organization, said the tour showed that more funding is needed to combat leafy spurge.

“(It’s) really impressive to see the progress being made through a variety of things such as the grazing with the sheep and the goats,” he said. “There’s always new chemicals being developed that will help control, and then the beetles, so usually a combination of efforts produce the best results.”

For more information, visit the Native Plant Society of Saskatchewan at www.npss.sk.ca.

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