Methodology
The 2025 survey covered the canola growing areas of southern and central Alberta. 257 fields in 51 municipalities were sampled in late June to early July when canola was at 20 to 25% flower. Surveyors sample by taking 25, 180 degree sweeps through the crop starting at the field edge and walking toward the centre of the field.
2026 spring update
As of March 2026, we are anticipating variable, but generally low overwintering mortality of cabbage seedpod weevil. Winter conditions have been generally mild. Overwintering mortality in southern Alberta is likely quite low. Areas in central and East-central Alberta that had low snow cover may have received enough cold temperatures to reduce weevil populations by close to 50 percent.
This map does not take the fall population into account. However, scouting for cabbage seedpod weevil will be very important in 2026.
Cabbage seedpod weevil was found in high numbers in the 2025 survey. The survey found the weevil above economic levels in southern Alberta as well as into central Alberta. Numbers of weevils were particularly high in the Highway 3 corridor but were not confined to distinct hotspots.
In 2026, it will be important to scout for cabbage seedpod weevil across the south and central regions. Scout canola when in early flower, especially those first to flower fields, to make control decisions. If control is warranted, make sure to follow economic thresholds and best management practices to protect pollinators.
In 2025, we found weevils above economic levels as far north as Red Deer County, which is unusual. Individual weevils were found as far north as Yellowhead County. These counts were well below threshold, but this is farther north than we usually see the weevil.
Agriculture and Agri-Food Canada at Beaverlodge conducts the canola survey in the Peace River region where no cabbage seedpod weevils have yet been found.
Cabbage seedpod weevil overwinters as an adult, so the risk of infestation is further indicated by the adult population of the preceding fall. High numbers of weevil adults in fall will likely mean significant infestation levels in the following spring. This map does not adjust for the emergence of the new generation in the fall or overwintering conditions. Favourable weather conditions for the new generation of weevils may lead to higher numbers in the following year. These conditions include cooler temperatures and rainfall in August and mild winters with a heavy snowpack.
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