More than 20 cutworm species may damage Prairie crops, with five economically significant cutworm species described below. Spot spraying the affected patches and a pass or two in the surrounding crop can often be effective in limiting outbreaks.Ĭutworm curled up next to a canola plant (potentially after feeding on it)Ĭutworms can be a significant pest in canola. High populations are often localized, leading to expanding bare patches in fields as they consume all the canola plants in an area and move outward in search of more food. Determine if the population is patchy or evenly distributed throughout the field.More may be reached at 25 to 30 per cent stand reduction. due to feeding/insect pest damage) exceeds the cost of the chemical and its application. pest insect density) at which lost yield (ex. A nominal economic threshold An economic threshold is the level of infestation (ex.

After the second or third year of infestation, beneficial organism populations such as parasitic insects, viral diseases and bacterial infections usually build enough to begin bringing cutworm numbers down.Knowing the species of cutworm can be important because some species complete the larval stages earlier in the year than others, and some species are more likely to feed on and clip stems than others.

Small larvae 12 to 18 millimetres (0.5 to 0.7 of an inch) pose the greatest potential for damage as they will still feed and grow.

Warmer, south facing slopes may show damage first. Scout the fields and inspect seedlings every three to four days during the first few weeks of crop development, looking for bare areas, holes or notches in foliage, and plants that are wilting, toppling over or completely cut off.

The key to minimizing damage is early detection.

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