Proper identification of cutworms and armyworms can be difficult. Usually, larvae are hard to find, and identifying characters may not be as prevalent on younger specimens.
I developed the following guide to help distinguish between winter cutworm (Noctua pronuba), variegated cutworm (Peridroma saucia), and true armyworm (Mythimna unipuncta). It is possible that growers and gardeners might encounter any or all of these species (as larvae) year round in the PNW.
All photos used with permission.