Wheat Stem Sawfly

In the last couple weeks, there has been a noticeable amount of wheat stem sawfly presence in wheat and durum fields. The adults are wasp-like insects that are shiny, black, have three strips along the abdomen and have yellow legs. They also normally land on the wheat stem and face the ground when they are laying their egg in the stem. Right now, the adults are moving into wheat crops from the neighboring wheat stubble, where they overwintered after last years crop.

There are no insecticide control options for these pests yet but research is being done looking into new options. When planning for next years rotation, it is good to consider varieties that are solid stem and utilize the Saskatchewan wheat stem sawfly survey to help get a picture of where hot spots are. Having a solid stem variety inhibits the development and slows the movement of the larvae within the stem, which results in increased larvae mortality. Typical damage from feeding on the pith inside the stem can reduce yield and quality, and feeding at the base of the stem can cause lodging. Sawfly populations continue to increase in recent years since they favor dry weather cycles that have continued in the prairies for another year.