Black cutworm (Agrotis ipsilon)
Glassy cutworm (Apamea devastator)
Variegated cutworm (Peridroma saucia)
Winter cutworm (Noctua pronuba)
Pest description and crop damage Adult cutworms are medium to large moths but all damage is due to larval feeding. Larvae are typically 1 to 1.5 inches in length. Winter cutworm have black dashes that run the length of the larvae, bordered by a creamy-yellow line. Winter cutworm also has a tan head with 2 black arcs over the eyes. The black cutworm is light gray to almost black in color, with a greasy appearing texture and coarse granules of various sizes on the skin. The glassy cutworm larvae are glossy, semi-translucent with a greenish-white or grey body lacking body markings, and a prominent reddish-brown head. The variegated cutworm has a series of 4 to 7 small, yellow dorsal spots and the terminal (most posterior) body segment has a transverse yellow line and a black 'W', which is most evident on mature larvae. Winter cutworm and black cutworm are more common turfgrass pests than the glassy and variegated cutworm. Larval cutworm populations build as the summer progresses and damage typically occurs in the late fall or early winter when turfgrass growth slows, but larvae continue to feed on the turfgrass. Birds will also disrupt the turfgrass surface while feeding on the insects in the fall. Black cutworm feed on turfgrass maintained at a low height (greens and fairways) while winter cutworm feed on turfgrass in higher cut areas (lawns, sports fields, and golf course roughs).
Biology and life history Both winter cutworm and black cutworm overwinter as larvae and adults emerge throughout the spring and summer-May to August. In areas where spring adult emergence is observed (coastal Pacific Northwest), multiple generations per year are likely. Eggs are laid on host plants, and hatch after a few days. Young larvae feed only on foliage, although mature larvae develop a subterranean habit and may cut off plants at the surface and feed on them in their burrows. If the lawn has been aerated, cutworm larvae may be found in the late summer and fall in these holes and damage is apparent around them.
Scouting and thresholds Scouting for larvae should begin in the summer (June) and continue to the onset of cold weather (October). The action threshold for well-maintained turfgrass is 4 larvae per sq ft. Scout using a tablespoon of lemon scented dish soap in a five-gallon bucket of water. Apply the mixture and wait for 5 minutes. Larvae will emerge from the soil and thatch trying to escape the dish soap application.
Management-biological control
- Bacillus thuringiensis - Some formulations are OMRI-listed for organic use.
- beneficial nematodes
Management-chemical control
Products for home use
- bifenthrin-Restricted use
- carbaryl
- chlorantranilprole
- cyfluthrin
- gamma-cyhalothrin
- imidacloprid-Some neonicotinoids have been banned from use on public properties.
- lambda-cyhalothrin
- plant essential oils-Some formulations are OMRI-listed for organic use.
- spinosad - Some formulations are OMRI-listed for organic use.
Products for commercial use
- acephate
- azadiractin-Some formulations are OMRI-listed for organic use.
- beta-cyfluthrin
- bifenthrin-Restricted use
- bifenthrin + imidacloprid-Some neonicotinoids have been banned from use on public properties.
- capsaicin + allyl isothiocyanate
- carbaryl
- chlorantraniliprole
- clothianidin-Some neonicotinoids have been banned from use on public properties.
- clothianidin + bifenthrin-Restricted use
- cyfluthrin
- deltamethrin
- dinotefuran-Some neonicotinoids have been banned from use on public properties.
- esfenvalerate + prallethrin + piperonyl butoxide
- gamma-cyhalothrin
- imidacloprid-Some neonicotinoids have been banned from use on public properties.
- indoxacarb
- mint oil, geraniol + oil of rosemary-OMRI-listed for organic use.
- spinosad-Some formulations are OMRI-listed for organic use.
- tetraniliprole
- trichlorfon