Grasshoppers didn’t pose a serious threat to crops in most parts of Saskatchewan in 2024 — but a leading entomologist warned growers attending the recent Saskatchewan Agronomy Update conference not to be lulled into a false sense of security about the threat they could present this coming season.
James Tansey, an insect pest management specialist with the Saskatchewan Ministry of Agriculture, urged growers to be vigilant, even though grasshopper numbers were relatively low in many parts of the province in 2024. The one exception was the province’s southwest.
There were two main reasons for those lower numbers overall. Cool, wet conditions in the spring slowed the embryonic development of several insect pests including grasshoppers. Those damp conditions also led to a rise in naturally occurring fungal diseases such as Entomophaga grylli, which can be lethal to grasshoppers and help keep their numbers in check.
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The concern now is that hot, dry conditions in many parts of the province in mid to late summer and well into the fall of 2024 provided ideal conditions for female grasshoppers to lay their eggs, says Tansey. That could lead to a large increase in the province’s grasshopper population if conditions are warm and dry this coming spring.
“If we get another warm spring like we saw in 2023, then we could certainly see a significant increase in grasshoppers again,” Tansey says.
“Are we going to see the numbers like we saw in 2023? Unlikely, but it could still be a major regional issue. I think growers need to keep their eyes open, so they’re not surprised if we do have a long, dry spring.”
Tansey says it could have been a much different story about grasshopper pressure in 2024 had last the spring been warm and dry. In the few parts of the province where conditions were warm and dry, very high numbers of eggs were placed in the ground and grasshopper populations in those locations “took hold with enthusiasm and they really sped through… development relatively quickly.”
There are more than 80 different species of grasshoppers present in the Prairies but only a handful pose a risk to crops, Tansey told the audience at the Agronomy Update.
The migratory grasshopper has historically been one of Saskatchewan’s major pests but has been supplanted recently by the two-striped grasshopper.
One of the main differences between the two species is that migratory grasshoppers are ambivorous and will eat “anything green that’s not nailed down” while their two-striped counterparts are folivorous and prefer broad-leafed crops such as canola and pulses.
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Another insect pest Tansey says growers should be on guard against this coming spring is Hessian flies: small, mosquito-like insects that pose a serious threat to cereal crops such as wheat, barley and rye. They can cause serious damage to a crop and are considered one of the worst cereal pests in the world.
Tansey says Hessian flies had not been reported as a significant pest in Saskatchewan since around 2013 or 2014, but the province recorded a significant uptick in their numbers in 2023, which continues to be a cause for concern. Significant populations were noted in North Battleford, Demaine, Leroy, Carstairs and Shaunavon in 2023.
One of the most common signs that Hessian flies are present in a crop is lodging. Tansey says if the stem of a plant is broken off at its second or third node the damage was likely cause by the tiny flies. However, if a cereal plant’s stem is broken near its first node, the damage was likely caused by wheat stem sawflies.
There are no pesticides registered to control Hessian flies. The primary means of controlling them is regular crop rotation.
Tansey adds that tillage can be effective in helping to control Hessian fly populations but “tillage comes with its own challenges, so you need to weigh that as well.”
ALSO: Gophers go further
A vertebrate pest plaguing Saskatchewan growers for some time now is Richardson’s ground squirrels — more commonly known as gophers.
They were particularly a problem for the province’s canola growers in 2024. Last spring’s cool, wet conditions meant canola crops were slow to develop in many regions. Gophers normally tend to congregate near the edge of a canola field because they don’t like tall plants that can block their sightlines.
However, because last year’s crop was late to develop, they were able to move further into fields and establish more of a presence.
“They were munching on those seedlings and pretty severely in some cases,” says Tansey.
Tansey says it’s too soon to say how much of threat Richardson’s ground squirrels will pose in 2025 and it will depend in part on what kind of weather the province experiences this spring. He points out the province is continuing to track their presence through an online survey available to farmers. He is currently working on a model that will use AI to incorporate that data and provide some predictive power about where they could pose a threat to crops.
In 2023, the federal Pest Management Regulatory Authority deregistered the use of strychnine to control gophers. The Saskatchewan Ministry of Agriculture has since been studying the effectiveness of some alternative products that farmers can use in place of strychnine.
Tansey says several zinc phosphide products such as Burrow Oat Bait and ZC Rodent Oat Bait appear to be statistically similar to strychnine in terms of their efficiency. An added bonus of their use is that zinc phosphide breaks down into gas which later escapes the cadaver and leaves little in the way of residue in a field. Some anticoagulants, including Rozol RTU Field Rodent Bait and Ramik Green, have also been shown to be effective.
The key to using any kind of poison bait products, Tansey says, is to install them early before crops start to emerge and gophers develop “bait shyness.”
