Growers all across the Prairies are spraying for cutworm. The 3 key species — redbacked, pale western and dingy — feed until they’re an inch to inch-and-a-half long, the molting stage. Redbacked tend to feed longer in the season than the other two. Scott Meers, entomologist with Alberta Agriculture, says many cutworms are still under an inch long, for the most part, and “the worst might not be over” for some regions.
Assessing the risk: Cutworms tend to be more numerous on fields that had a lot of green and growing plants (including weeds) the previous fall, and that had been in pulses the year before. Cutworms can reach economic levels regardless of the previous crop. Scout all your canola fields.
Crop damage: Look for cut, wilted or missing canola plants. Cutworms are often in patches, so spot spraying affected acres may be enough. Evening spraying is optimal as cutworms come closer to the surface at night. Morning sprays are less effective as cutworms move deeper at first light of day. For more scouting and spraying tips, click here for a MAFRI factsheet.
Check insecticide labels to make sure a product works on cutworms.