Some pests were more prevalent in Saskatchewan compared to others this season, according to the Saskatchewan Ministry of Agriculture's Provincial Insect and Vertebrate Pest Management Specialist.
Dr. James Tansey talked to SaskAgToday about the prevalence of cabbage seedpod weevil, pea leaf weevil, grasshoppers, bertha army worms, and aphids in Saskatchewan fields. His comments were made in advance of the 2026 surveys, which are usually released in November.
Starting with the bertha army worm, Tansey noted there were outbreaks around Saskatoon, Outlook and an area extending west towards the Alberta boundary.
There were also reports of bertha army worms in parts of the south, including the southeast, and northeast of Saskatchewan.
Tansey said outbreaks typically last two to three years and with this year being the second outbreak, he expects a third outbreak for 2027.
"We will, of course, continue to monitor their populations, but we expect that outbreak to terminate within the next year."
What usually controls the population of bertha army worm is a disease called baculovirus, he said.
"So for those who've been in a canola field and you've seen those hanging bags of yuck, that is what happens to a birth armyworm after it's been infected with this baculovirus. It causes what's called puddling…so it actually liquefies the inside of the birth armyworm caterpillar, and when that bag bursts, of course, it's going to rain down virus particles onto the leaves where these can be consumed by other birth armyworm…and this is what finally brings outbreaks to an end."
He believes the bertha army worms have reached peak emergence.
As for what can be done in the future, he recommended monitoring fields to determine what the field-wide population is, but admitted it is labour intensive.
"So what needs to occur is you actually go into the field, mark out a meter by a meter, knock all the insects off the plants, because they do tend to fall off the plants, and are primarily night active. So they're going to be down in the leaf litter and count them up. And you need to pick through the leaf litter to determine how many are there, and then you determine the number per square meter based on that. Don't ever just look at one site and make an evaluation. Look at multiple samples at each individual site. And look at at least five sites in a field to determine what your field-wide population is."
Canola and lentils were the main targets for bertha army worms.
Aphids
Pea aphids have been growing over the last two to three years, Tansey said, and prefer pulse crops such as field peas and lentils, especially the latter during the flowering and early pod stage of development.
He notes pea aphids are now showing resistance to Group 3 insecticides. While there are other insecticide groups registered to control aphids, "they are a little bit more expensive, and there can be some trade considerations associated with that," using green lentil exports to Europe as an example.
"There's an active ingredient called flonicamid, and the Europeans have expressed some concerns about that on lentils, and that could have a trade impact," Tansey said.
According to the 2026 Keep it Clean Product Advisory – an initiative between the Canola Council of Canada, Cereals Canada, Pulse Canada, and the Prairie Oat Growers Association – it listed flonicamid under the "Be informed" category for use on green lentils as "treated green lentils may not be accepted by some grain buyers."
Another reason is maximum residue limit uncertainties in the European Union.
The Keep it Clean initiative advises producers to consult with their grain buyer before using flonicamid on green lentils and so does Tansey, who goes a step further to recommend checking what is permitted and what trade restrictions are associated with where a crop is going worldwide.
While pea aphids can't do more damage to lentils since the crop is being harvested, Tansey said the winged adult aphids will move to fababeans.
He adds there have been issues with cereal aphids, but cereal crops are past the point of being influenced by aphids.
Grasshoppers
Regarding grasshoppers, Tansey said they weren't much of a nuisance to crops this year compared to previous years.
"Last year was a pretty cool year for grasshoppers, this year is another pretty cool year for grasshoppers, and this is one that's going to really respond to environmental conditions. So we had a very cool wet spring this year, and that is going to slow down their development and can result in the outbreak of fungal diseases and bacterial diseases in grasshopper populations.”
“So we are seeing a few minor areas that are requiring some control, or we've heard some reports of damage, but these are highly limited this year."
However, the two-stripped grasshopper made a comeback this year and a survey on 1,400 sites across the province is ongoing for prevalence.
“It's a very important survey, so we're anxiously awaiting all that data to be compiled so we get a real feel of what's going on provincially with the grasshopper population. We will publish that map, probably in November, on the Ministry website, and we'll forward that off to the Prairie Pest Monitoring Network website as well.” he said.
Last year's survey map showed areas with moderate to severe grasshopper populations included the R.M.s of Coteau, King George, Monet, Eyebrow, and Hillsborough.
Cabbage Seedpod Weevil
Cabbage Seedpod Weevil made its presence known this season in Saskatchewan.
Tansey recalled a significant population last year in areas where "in previous years they haven't been either accounted for or detected or were not detected at very large numbers", including eastern areas and into Manitoba.
"They've continued to move in those areas. It is an invasive species, so it does continue to move north and it does continue to move east. It was a pretty significant problem in a number of areas in the province this year." he said.
They are attracted to canola flowers "which indicate a suitable food source and egg laying location", according to the Canola Council of Canada's overview of the insect.
Tansey notes a female can lay up to 300 eggs, so "there is the potential for a single cabbage seed pod weevil female to influence 300 pods."
"We had a lot of spray going down for cabbage seed pod weevil this year over quite a broad area," added Tansey. "We're seeing emergence of what's called the overwintering generation, or the adults that will be seen next spring. They're looking like they're going to be pretty numerous next year as well."
But the caveat, he said, is how much snow pack there will be this winter. If there is a lot, the cabbage seedpod weevil population will definitely increase next year, but if there is very little, then it could be reduced since it isn't tolerant to the cold.
Last year's survey map indicates a high presence of cabbage seedpod weevil across southern and central Saskatchewan.
It was first reported in Canada in the Lethbridge area in 1995, then in Saskatchewan five years later.
Pea Leaf Weevil
Similar to cabbage seedpod weevil, the pea leaf weevil continues to be an issue for the eastern Saskatchewan with elevated populations last year and this year, "although it was slightly more muted this year", said Tansey.
And like the cabbage seedpod weevil, how large the population of pea leaf weevil will be next year depends on snow cover.
"So if we get heavy snow cover in eastern regions, then growers should probably consider buying a seed treatment for control of pea leaf weevil." he said. "There are products available to control larval feeding on the rhizobium nodules, and that's where they're really going to be causing the economic hit on these ones."
According to the 2025 survey, pea leaf weevil was reported in the northwest and throughout the east with the highest populations around the Preeceville and Canora areas.
