Cutworm are caterpillars measuring around 4cm long and very soft-bodied and hairless. They curl up when they are disturbed.
Cutworm (left)-Clemson State University, Cutworms (right)-Marlin E. Price
They are moth larva and are usually black in colour (also can be grayish brown) and have a yellow line down their backs. The eggs of the moth are small and white and laid in clumps. There are different types, surface type that feed on leaves, climbing type that climb your plants at night and eat fruits veggies and flowers and soil types that stay in the ground and cut off the plant at the root.
Adult Cutworm Moth-(left)-Oregon State University, Diagram (right)-University of California
Habitat and Lifecycle
They are found all over Canada and the United States. The adult moths lay their eggs in grass or weeds. They attack beans, tomatoes, cole crops, peppers, peas and many flowers. (I had a big problem with my dahlias) There can be as many as 4 hatchings of these guys depending where you live. They are usually more numerous in areas where the grass has recently been removed.
Damage on Soybeans-Iowa State University
You will know if you have a cutworm problem if you wake up one morning and see your young seedlings ‘cut off’, wilted or dead on the ground. A single cutworm can kill many seedlings in a few days.
1) Hand Pick
In the evening cutworms crawl up the plant and feed so with a flashlight in hand you should be able to pick them off. For soil ones, if you see evidence of cutworms then you can lightly dig around a plant with a fork and pick them out. The pupae is a brownish to greyish colour.
2) Remove Weeds and Debris
Cutworms over winter in these areas so this is a preventative measure
3) Sticky Traps
These will catch the moth that lays eggs for over wintering
4) Plant Collars
Use a stiff piece of plastic collar (ie….a sour cream container with the bottom cut out) around the
stems; with at least an inch buried in the ground and twice that protruding upwards. Place the seedling in the center. When the seedlings are bigger chances of cutworms lessons.
BT is safe as it makes the worms sick the first or second day and then they die rapidly.