Grain Grading Tools

Midge damage (MDGE DMG)

The Orange Blossom Wheat Midge (Sitodiplosis mosellana) (Government of Alberta, Alberta Agriculture, Food and Rural Development) causes midge-damaged kernels. This pest is found in wheat-growing areas of Europe, Asia and North America. The orange fly deposits its eggs on the floret and then the hatching larvae feed on the developing grain.

Midge damage is an objective grading factor.

The photo galleries show kernels of Canada Western Red Spring wheat and Canada Western Amber Durum wheat affected by midge damage.

Midge-damaged kernels are distinctly shrunken or distorted. They are characterized by a depression or caved-in side marked by a scarred pericarp. The pericarp is frequently ruptured, exposing the endosperm.

To assess midge 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.

More information on the effects of midge damage on processing is available in Grain Research Laboratory papers on factors affecting processing performance of common wheat.

Do you have a grading question? To find an answer, contact

Louise Sartorio
Manager, Inspector Training and Development
Telephone: (204) 983-4500
Email: lsartorio@grainscanada.gc.ca