More Cutworms Appearing

Reports of cutworms continued this week across western Canada. Cutworm damage often appears as bare patches showing up across the field. Plants in these areas will be wilted or dead and have been chewed off below the soil surface. Generally the pale western and red-backed cutworms are of economic importance in canola on the Prairies. Other cutworm species have been reported (e.g. Bronzed and Dingy) this year. Dingy cutworm larvae have a dull, dingy brown body with mottled pigmentation. A broad gray stripe runs along the back with light gray V shaped patterns on each segment. Fully developed larvae are one to 1 1/2 inches (25 to 32 millimeter) in length. Photos of dingy cutworm larvae and more information on cutworms in general can be found at:

http://www.gov.mb.ca/agriculture/crops/insects/fad06s00.html or
http://www.ent.iastate.edu/imagegal/lepidoptera/bcutworm/3936.105cwcompare.html

Use a garden trowel and soil sifter to collect cutworm larvae. Cutworms may be found in dry surface soil down to about two inches below the surface. The small, worm-like larvae curl up or attempt to hide in debris. Cutworm control may only be necessary in a limited area of the field. An insecticide is warranted when cutworms exceed three to four larvae per m2 and are actively feeding. Surface treatments should be applied in the evening, preferably under warm, moist conditions, because cutworms are active at night and these treatments will only control surface-feeding larvae. More information on cutworms is available at:
https://canolacouncil.merchantsecure.com/canola_resources/product22.aspx