In 2025, wheat midge populations were low across the province.
Numbers of the parasitoid Macroglenes penetrans increased in 2025, with an overall parasitism rate of 23%.
Even though the map may indicate that there is not a risk for midge in a specific area, that does not mean that there is no risk. Historically, field-to-field variation has been considerable for this insect and individual fields may have economic levels of midge.
For information on identification, life cycle, damage and pest management, see Wheat midge – Overview.
Methodology
In total, 298 samples were taken from 62 counties. The survey involves taking soil samples from wheat fields after harvest using a standard soil probe. Larval cocoons are washed out of the soil using a specialized series of screens. Larvae are counted and then dissected to determine parasitism levels in the midge. The midge density displayed on the forecast map is based on viable (live, non-parasitized) midge larvae.
Low numbers of wheat midge were found distributed throughout the province, except in the Peace Region, where none were found. Wheat development in the Peace region was well ahead of the long-term average at the time when adult wheat midge pheromone trap capture peaked, so the midge may have missed susceptible wheat growth stages.
Trap capture from pheromone baited traps indicated wheat midge emergence peaked during the second week of July over most of the province.
Overall parasitism rates were 23% in infested fields, increasing from 6% in 2024. In fields where parasitoids were present, rates varied from 25% to 50%. Parasitism rates were particularly high in central Alberta. Adequate moisture conditions can be even more important for the parasitoids than for the midge.
This map is not intended to take the place of monitoring populations in individual fields as populations of this insect often are highly variable.
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