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Ministry of Agriculture, Food and Rural Affairs

Cabbage Looper

Cabbage looper larva Cabbage looper feeding damage
Click to enlarge.

Beginner

Scientific Name
Trichoplusia ni

Identification
Adult cabbage looper are mottled greyish-brown moths have a distinctive silvery figure eight pattern on their forewings and a slight tuft of hair behind the head with a wingspan of about 3.8 cm. Eggs are small, rounded and greenish-white, usually in small groups on the underside margins of leaves. Cabbage looper larvae are light green with a white strip along each side of the body and two faint lines down the middle of the back.  Since their legs are confined to the front and rear of the body, they move in a very distinctive “looping” manner, which can be used to distinguish them from the imported cabbage worm and the diamondback moth. At maturity, cabbage looper larvae are about 4 cm long. The pupa is initially light green in a loose cocoon, darkening in color as it matures.

Often Confused With
N/A

Period of Activity
Depending upon temperatures and wind patterns, cabbage looper adults arrive in Ontario in midsummer to early fall. After eggs are laid, larvae hatch in 3– 4 days and begin feeding. The larvae mature in about 2 weeks and pupate. The pupal stage lasts about 2– 3 weeks and adult moths emerge. There may be 1–2 generations in southern Ontario depending upon the time of arrival and temperatures during August and September.

Scouting Notes
Similar to scouting guidelines recommended for common insect pests.

Thresholds
This pest rarely causes economic damage. No thresholds are established.

Advanced

Scientific Name
Trichoplusia ni

Identification
Adult cabbage looper are mottled greyish-brown moths have a distinctive silvery figure eight pattern on their forewings and a slight tuft of hair behind the head with a wingspan of about 3.8 cm. Eggs are small, rounded and greenish-white, usually in small groups on the underside margins of leaves. Cabbage looper larvae are light green with a white strip along each side of the body and two faint lines down the middle of the back.  Since their legs are confined to the front and rear of the body, they move in a very distinctive “looping” manner, which can be used to distinguish them from the imported cabbage worm and the diamondback moth. At maturity, cabbage looper larvae are about 4 cm long. The pupa is initially light green in a loose cocoon, darkening in color as it matures.

Often Confused With
N/A

Biology
Life stages: eggs, larvae, pupae, adult moths.

The adult cabbage looper moth is generally nocturnal, but can sometimes be found resting on the underside of cabbage leaves during the day. Adult female cabbage looper lay several hundred small, rounded, white eggs, usually in small groups on the underside margins of leaves.  Larvae hatch after 3- 4 days and begin feeding. During this feeding time, the larvae develop through 5 instars in 2- 3 weeks. After such time, cabbage looper larvae pupate in webbed cocoons often on the underside of the host plants. This stage lasts about 2 weeks.
The cabbage looper is a sporadic pest of potatoes. Unlike cutworms, loopers feed on potato plants during the day. They arch into a loop as they crawl.

Period of Activity
Depending upon temperatures and wind patterns, cabbage looper adults arrive in Ontario in midsummer to early fall. After eggs are laid, larvae hatch in 3– 4 days and begin feeding. The larvae mature in about 2 weeks and pupate. The pupal stage lasts about 2– 3 weeks and adult moths emerge. There may be 1–2 generations in southern Ontario depending upon the time of arrival and temperatures during August and September.

Scouting Notes
Similar to scouting guidelines recommended for common insect pests.

Thresholds
This pest rarely causes economic damage. No thresholds are established.

Management Notes
The cabbage looper is an occasional pest of extremely low incidence.  Insecticide applications are not required.