Wheat Midge Populations Rising in Central and Southeast Saskatchewan — Varietal Blend Decision Due at Seeding
Canadian Crop Conditions
Saskatchewan’s 2025 wheat midge survey confirms that producers seeding spring wheat in central and southeast Saskatchewan this spring are operating in elevated pest risk territory. The population data, collected by the Saskatchewan Ministry of Agriculture from 414 soil sample sites across the provincial wheat growing region in fall 2025, shows midge populations comparable to 2024 levels and in approximately the same geographic pattern. A hotspot near Regina continued to expand, with elevated populations across large areas of central and southeast Saskatchewan and elevated numbers also detected in the east. The 2025 survey result follows a 2024 survey that itself recorded a significant increase over 2023. Two consecutive years of elevated populations in the same core regions represents a material risk signal for the 2026 growing season.
The biology of this pest compounds the planning challenge. The Saskatchewan Ministry of Agriculture notes that wheat midge can lie dormant in the soil for years before emerging, and that favourable environmental conditions — specifically timely rains prior to the end of May — can promote larval development and the emergence of adults in late June and early July regardless of what the survey map shows for a given region. Producers in areas mapped at lower risk should not treat that as a clearance; field-to-field variation is considerable and individual fields can reach economic infestation levels in any year.
In Alberta, the 2025 picture is materially different. Alberta Agriculture’s 2025 survey, covering 298 samples from 62 counties, found low wheat midge populations distributed throughout the province. The parasitoid wasp Macroglenes penetrans — the primary natural check on midge populations — recorded an overall parasitism rate of 23% in infested Alberta fields, up from 6% in 2024, with rates of 25% to 50% in fields where parasitoids were present. Alberta Agriculture notes that parasitism rates were particularly high in central Alberta, and that adequate moisture conditions favour the parasitoid as much as or more than the midge itself. The contrast between Saskatchewan and Alberta population levels this year is significant for variety selection and risk management planning.
The economic stakes of unmanaged midge infestation are well-established. The Saskatchewan Ministry of Agriculture’s data shows that infestation levels of one adult midge per four to five wheat heads can reduce yield by approximately 15 per cent if left uncontrolled. Yield loss increases with higher midge density. Grade loss runs parallel: Canadian Grain Commission standards limit midge-damaged kernels in No. 1 CWRS to 2 per cent and in No. 2 CWRS to 8 per cent before grade is affected. For No. 1 Canadian Western Amber Durum, the tolerance is also 2 per cent, dropping to 0.1 per cent where disease is associated with the midge damage. At current CWRS price forecasts of $265 per tonne for 2025-26 and $275 per tonne for 2026-27, a grade slip from No. 1 to No. 2 or lower carries direct marketing consequences that compound the yield penalty.
The primary production-level response available at seeding is the midge tolerant wheat (WMT) varietal blend system. Developed through breeding research conducted at the Agriculture and Agri-Food Canada (AAFC) Cereals Research Centre in Winnipeg and the University of Saskatchewan Crop Development Centre, the system centres on the Sm1 gene — the only known genetic source of tolerance to the orange blossom wheat midge. It took more than 15 years of traditional plant breeding to move this single gene into commercial wheat varieties. AAFC-registered midge tolerant varieties carrying the Sm1 gene are available across all major spring wheat classes. For 2026, the Saskatchewan Ministry of Agriculture confirms that varietal blends (VBs) are registered and available in CWRS, CPSR, CWSP, CWSWS, CWHWS, and Durum wheat classes.
Seed is sold as a varietal blend — 90 per cent midge tolerant variety combined with 10 per cent midge-susceptible refuge seed of the same class. The refuge component is not optional. The blend structure is a deliberate stewardship mechanism: the 10 per cent susceptible refuge creates an interspersed population of susceptible plants that disrupts the midge’s ability to develop resistance to the Sm1 gene. Without this refuge system, the Sm1 tolerance trait is projected to break down within approximately 10 years as midge populations adapt. Because the tolerance is based on a single gene, there is no second genetic backstop. Growers purchasing WMT seed are required to sign a Stewardship Agreement confirming they will maintain the refuge and limit farm-saved seed use to one generation past certified seed. Seed saved beyond that threshold cannot be confirmed to carry the refuge at the required 10 per cent level.
Producers should check the current Saskatchewan Seed Guide for the full list of registered WMT varietal blends available for 2026 and their performance data, and consult the Saskatchewan Ministry of Agriculture wheat midge survey map to assess the risk profile for their specific region before finalizing variety selections.
Sources: Saskatchewan Ministry of Agriculture, Wheat Midge Survey Map, 2025 survey data | Saskatchewan Ministry of Agriculture, Wheat Midge — Overview and Control Methods | Alberta Agriculture and Irrigation, Wheat Midge — Survey and Maps, 2025 survey data | Agriculture and Agri-Food Canada, Outlook for Principal Field Crops, March 18, 2026
Decision Context
One external signal is directly relevant to the variety selection decision for 2026.
CWRS grade integrity and export market access. Canadian Grain Commission grading tolerances for midge damage are fixed, and midge damage that tips grain below No. 1 CWRS has immediate consequences for export premiums in Saskatchewan’s primary markets. AAFC’s March 2026 Outlook notes that 2025 CWRS quality was strong — 71 per cent of samples graded No. 1, average protein at 13.7 per cent — and that export pace is running 6 per cent above the prior year. That export momentum depends on consistent delivery of No. 1 and No. 2 CWRS to buyers in Southeast Asia, the Middle East, and North Africa. A midge-damaged crop year that degrades a meaningful share of Saskatchewan’s CWRS production into lower grades would directly compress the export premium that is currently supporting both price and movement pace. In elevated-risk zones, the WMT varietal blend is the most cost-effective tool for protecting grade position at seeding, before the growing season’s moisture and temperature conditions determine whether dormant midge populations activate. WFR Asia Intel
What to Watch
Saskatchewan Ministry of Agriculture weekly crop report — weekly from April 1 through late October. Reports beginning in late June will include in-season wheat midge adult monitoring results. Producers in elevated-risk zones should cross-reference these reports against their own field scouting during the boot-split to mid-flowering window to determine whether an insecticide application threshold is being approached in fields seeded to conventional varieties. Source: Saskatchewan Ministry of Agriculture crop report series
Alberta Agriculture wheat midge pheromone trap results — released in June and July, tracking adult midge emergence timing. Relevant for Alberta producers in the central and south regions where scattered field-level risk persists despite the low provincial survey result. Source: Alberta Agriculture, Wheat Midge — Survey and Maps
Canadian Grain Commission in-season grade monitoring — CGC commercial grain inspection data through the licensed elevator system will be the earliest signal of whether midge damage is affecting grade distribution in the 2026 crop. Monitor CGC weekly grain statistics from August onward. Source: Canadian Grain Commission weekly grain statistics
Saskatchewan Ministry of Agriculture, fall 2026 wheat midge survey — the definitive input for 2027 variety selection decisions. Results typically released in January 2027 at Crop Production Week, Saskatoon. Source: Saskatchewan Ministry of Agriculture.
Cross-Reference to Related WFR Coverage
Tags: wheat midge, midge tolerant wheat, varietal blend, CWRS, Saskatchewan, Alberta, wheat pest management, spring wheat, Sm1 gene, crop protection
This post was produced with AI assistance. All sources are attributed and linked. Western Farm Report editorial standards apply.