Winter cutworm (Noctua pronuba)
Black cutworm (Agrotis ipsilon)
Glassy cutworm (Apamea devastator)
Variegated cutworm (Peridroma saucia)
Pest description and crop damage Winter cutworm and black cutworm are more common turfgrass pests than the glassy and variegated cutworm. Cutworms are larval caterpillars 1 to 1.5 inches in length that live and feed on turfgrass above ground. Winter cutworm are green with black and tan dashes that run the length of the back, and have a tan head with a black line over the eyes. Black cutworm are gray to almost black in color with black dots that run the length of the back, and a black and brown head. The glassy cutworm is greenish-white with dots along the side of the body, and have a reddish-brown head with a brown line over the eyes. Variegated cutworm have yellow spots and black dashes that run the length of the back, and have a black and brown head.
Larval cutworm populations build as the summer progresses and damage typically occurs in the late fall or early winter when turfgrass growth slows, and larvae continue to feed. 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. 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. Larvae burrow through the thatch layer and feed on turfgrass foliage.
Scouting and thresholds Scouting for larvae should begin in the summer and continue to the onset of cold weather. 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 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
- chlorantraniliprole
- 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