Armyworms in lawns
In lawns the damage has a telltale edge: a clear line between eaten and uneaten grass that moves across the lawn as the larvae feed. It often starts near signposts or buildings, where moths lay their egg masses. New sod is especially attractive. Nematodes suit caterpillars moving through thatch, but UC IPM says to apply them to warm, moist (not soggy) soil during the coolest part of the day, and to keep it moist for two weeks.
At a glance
- Damage
- Lawns browned in a moving front; ragged corn whorls full of frass
- Type
- Chewing
- Settings
- Garden, Field
- Threshold
- 5 armyworms per yd² in a soap flush (UC IPM)
- Release
- Steinernema carpocapsae
- Rate
- 25 million S. carpocapsae per 1,000 ft² (about 270,000 /m²) for cutworms and armyworms (UC IPM)
How to confirm it
A striped caterpillar up to 1½ inches (4 cm) long with a pale upside-down Y on its dark head and four dark spots in a square on top of the eighth abdominal segment, near the rear end. In lawns, pour soapy water over the edge of the browning area and the caterpillars come to the surface within 10 minutes.
Identification, lifecycle, degree days and every control option are on the full Fall armyworm profile. Not sure it is this pest? Answer four questions about the damage.
Work it out
How many do I need?
Carries Steinernema carpocapsae and lawn & turf through so nothing is re-entered. Open the calculator →