The Growing Point | June 2019

What are my options for wheat stem sawfly?

The forecast for wheat stem sawfly in Alberta has increased from last year with areas of concern in the Forty Mile area, Foremost area, Taber over into Warner, Willow Creek, Vulcan and parts of Lethbridge. Unfortunately, our main line of defense for CWRS wheat, solid stem genetics, was lost when Lillian was moved to the CNHR class. CDC Adamant is currently registered as a semi-solid stem with resistance to wheat stem sawfly but I’ve heard limited feedback on its control performance. This leaves growers in those areas of concern at risk. Unfortunately, at this point there is no dependable control method for wheat stem sawfly. If this pest continues to grow as an issue, breeding programs will need to adjust priorities to account for that.

For now, your best defense is observation and proper rotation. Wheat on wheat fields typically see greater damage due to the sawfly’s lifecycle. During the milk stage, check random stems for wheat stem sawfly infestation and damage. An infected stem will contain the larvae and sawdust like material from the burrowing larvae. If you have significant infestation, you may want to consider swathing the crop at 40% moisture to reduce losses from lodging.

Short of these options, switching back to Lillian may be necessary if pest pressure is high enough. Be sure to check with your local elevator to see what movement and pricing is available. If enough yield is lost to pest damage, it may be more economical to grow Lillian instead.