SARM wants strychnine back for gopher control
April 30, 2025, 10:02 am
Ryan Kiedrowski, Local Journalism Initiative Reporter
As the spring melt begins, a familiar sight will emerge from the ground—one that those who make a living off the land consider a scourge. Gophers are notorious for causing widespread damage to crops and pastureland. Previously, the use of strychnine was a powerful and effective tool for gopher control, but a federal ban on the pesticide in 2024 halted all use. One group in particular has recently called for the reintroduction of strychnine to control gophers, calling it “a crucial tool used by farmers to control growing gopher populations in rural municipalities.”
“It has been a year since the ban came into full effect and our farmers are struggling to find a practical and effective method to control the Richardson’s Ground Squirrel populations. SARM is asking the provincial government to use The Saskatchewan First Act to reintroduce the use of strychnine specifically for gopher control,” says Bill Huber, Saskatchewan Association of Rural Municipalities President.
Strychnine was banned due to secondary mortality rates as predators became ill from consuming gophers that had ingested strychnine, but SARM feels that when applied according to label instructions, the pesticide is “an effective and low risk method” for gopher control. SARM is calling for the provincial government to use the powers of The Saskatchewan First Act to reinstate strychnine use in the province.
“In 2020, the Pest Management Regulatory Agency (PMRA) cancelled all uses of strychnine for burrowing rodent control in Canada, particularly Richardson’s Ground Squirrel, with the last permitted use being March 2023,” said provincial Agriculture Minister, Daryl Harrison. “The Ministry of Agriculture submitted a notice of objection which did not prompt any changes to this decision.”
Conditions may be right for a gopher explosion this year, as Harrison noted the pest’s abundance last year.
“RGS was a significant pest in several regions of the province in 2024, most notably in seedling canola,” he said. “It is likely that slow stand establishment contributed to movement of ground squirrels deeper into fields than is normally seen.”
Timing is crucial in terms of gopher control as early spring is optimal for applying rodenticide. Adult male gophers tend to emerge first, usually mid-February to early March, followed by adult females in early to mid-March. Juvenile gophers usually emerge early to mid-May.
“Both crop and beef producers are certainly used to strychnine. They found it very effective and convenient to use,” Harrison said. “It’s the old standby, but there are other products out there, and they are effective, but what really is hard for producers is the timely application of that product. It’s important to get it out there before the grass starts to green up for it to be fully effective. That’s what the producers miss, is that flexibility. I think if they keep learning and understanding on the product, they’ll find an effective control.”
Strychnine sales were permitted until March 4, 2022, a year after the PMRA’s decision to de-register the pesticide. It was allowed to be used for a further year, then not allowed after March, 2023. By nature, strychnine is highly toxic, causing respiratory failure and has no antidote if consumed. It was sold in the form of two per cent liquid concentrate, requiring mixing with grain to achieve an application concentration of 0.4 per cent.
“The Government of Saskatchewan continues to be disappointed with the de-registration of strychnine for RGS control,” Harrison noted. “We believe the science indicates that this product, when used according to label instructions, is effective and presents the best option for controlling RGS populations in the province and mitigating the significant impacts on agriculture operations.”
Zinc phosphide is an effective alternative that affects the central nervous system, found in ZP Rodent Oat Bait AG and Burrow Oat Bait. There are also anticoagulant pellets, which require re-baiting after two days.
“Zinc phosphide has been called a new gopher control product. It is not, it was first synthesized in the 1700s,” explained Dr. James Tansey, Provincial Specialist, Insect/Pest Management, Production Technology, Crops and Irrigation Branch, Saskatchewan Ministry of Agriculture during last week’s SARM conference in Saskatoon. “Once you get to about 50º C, it will break down. Sometimes the inside of a shed can heat up, and you need to be aware of that.”
Much like strychnine, zinc phosphide is a quick killer.
“It shuts down cell energy production,” Dr. Tansey explained. “So what this causes is necrosis in the heart, brain, kidneys and liver, and it works quickly. It can kill in 15 minutes, so they need to get an adequate dose of it. There’s also evidence now that it can act as a neurotoxin, so much like strychnine, where you get that convulsive reaction to poisoning, this can result in that too.”
As for the anticoagulants, Dr. Tansey noted application before gophers are literally surrounded by the antidote is crucial.
“Plants, grasses, legumes are full of vitamin K, so gophers after green up are basically surrounded by the antidote,” he said. “If they can take in enough of this plant material, they’ll get the antidote for this toxin, so that can be problematic.”
Of all the methods, anticoagulants are the slowest in terms of mortality.
“One potential downside for this is it takes a long time to kill, and it is a multiple feeding product,” Dr Tansey said. “It can take seven to 10 days to kill, and in that time, residues are building up in that animal and can present a hazard to non targets like scavengers and predators. Once again, multiple feedings and that residue issue.”
In terms of cost, liquid strychnine averaged around $13.28 per acre, compared to the oat bait, which cost $8.46 per acre for the Burrow Oat Bait and $6.74 per acre for the rodent oat bait.
As for the anticoagulants, Rozol RTU Field Rodent Bait came in as the most expensive at $21.86 per acre, and Ramik Green at $12.34 per acre.
