This insect can be a serious pest of canola and other cruciferous crops, including mustard, cabbage, rutabaga, radishes, cauliflower and broccoli.
Polish canola is more susceptible than Argentine canola.
The adult stage is a fly that emerges in the spring or early summer from over- wintering cocoons in the soil. It looks like a common house fly but is smaller and ash grey in colour with a dark stripe along the back of the abdomen. A second adult emergence may occur later in the summer as the first generation completes its life cycle. Thus, maggots can be found throughout most of the growing season. Each female fly will lay 50 to 200 eggs.