By Janet Knodel
Soil samples from North Dakota counties indicate low levels of overwintering wheat midge larvae (cocoons) for the 2026 season.
“This is the first time since the inception of the survey in 1995 that zero wheat midge cocoons were found in the fall soil survey for the overwintering cocoons of wheat midge,” says Janet Knodel, North Dakota State University Extension entomologist.
2025 was the sixth year in a row with a low number of wheat midge cocoons present in soil samples, potentially reducing farmers’ inputs for wheat midge management.
In fall 2025, NDSU Extension agents collected 1,970 soil samples (10 cores per field) from 197 fields in 21 northern North Dakota counties. Any larval cocoons would be extracted at the NDSU Extension entomology laboratory.
Historically, wheat midge has caused significant yield and quality losses in spring and durum wheat in the northern tier of North Dakota counties from the mid-1990s through 2010.
“The fact that zero wheat midge was detected in the 2025 soil survey indicates low overwintering populations and reduced risk of economic infestation for the upcoming growing season,” says Knodel.
The number of cocoons has been low, below 500 midge larvae per square meter, for the past 10 years. Low midge pressure is tied in part to dry weather and drought conditions, which hinder the successful emergence and overwintering of larvae, according to Knodel.
Source : ndsu.edu