The Wheat Stem Sawfly (Cephus cinctus Norton) (Saskatchewan Agriculture and Food) is thought to be native of North America. It is found in brown soil zone of Great Plains. It was first noticed in Canada in late 1800’s. The Sawfly insect attacks the stem of the plant hence stopping the flow of nutrients to feed the kernel.
Sawfly damage is an objective grading factor. Sawfly damaged kernels are shrivelled or distorted.

Shrivelled and distorted sawfly damaged kernels in a sample of Canadian Western Red Spring wheat.

Shrivelled and distorted sawfly damaged kernels
compared to a sound kernel of Canadian Western Red Spring wheat.
To assess sawfly damaged samples, the inspector performs a physical separation to assess the percentage of these damaged kernels in the sample. The number of grams utilized to perform the assessment is predetermined and defined in the Official Grain Grading Guide. The inspector will then apply the tolerances for midge and sawfly as set out in the Grade Determinant Tables found in the Official Grain Grading Guide.