Insect pest update – July 2025

With the season progressing, growers and agronomists are encouraged to keep a close eye on the economically important insect pests. This short article provides updates on developmental stages, thresholds, critical stages and live maps for grasshopper, wheat midge and wheat stem sawfly.  

Grasshoppers  

The average grasshopper stage across the province is third to fourth instar. However, fifth-instar two-striped grasshoppers and adult clear-winged grasshoppers are present across Alberta. Earlier this season, higher numbers of grasshoppers have been reported in Southern Alberta and the Peace Region. Considering the risks, agronomists are recommended to keep a close eye on grasshopper populations, and act accordingly based on the threshold.

Wheat midge 

Most areas of Alberta have received enough rainfall that wheat midge should develop as usual. In the regions where wheat midge populations are present, larvae are pupating and adults have begun to emerge. Midge pheromone traps have been put into the fields. Check out this map to track midge reports and populations.

Last fall, midge populations were low except for a few hotspots in the Northern Peace, in Barrhead County, and in irrigated fields in Southeast Alberta. However, monitoring for wheat midge during head emergence is still important. Wheat fields are susceptible from boot crack until anthesis. Include wheat midge in your scouting list during this growth stage. 

Figure 7. Percent of wheat midge larval population (Sitodiplosis mosellana) predicted to be in the pupal stage across western Canada, as of June 29, 2025. Map credit: PPMN.

Wheat stem sawfly  

Sawfly adults are active in fields. We are expecting that areas that traditionally see sawfly damage will see moderate damage again this year, particularly in Eastern and South-eastern Alberta.

Alberta Agriculture and Irrigation will start the annual post-harvest wheat midge and sawfly survey in late August. Producers who are interested, can sign up for the annual survey here.

Figure 8. Wheat stem sawfly adult. Photo source: Alberta Agriculture and Irrigation.