How to Manage Pests

UC Pest Management Guidelines


Cabbage Looper

Scientific Name: Trichoplusia ni

(Reviewed 4/10, updated 4/10, pesticides updated 5/16, corrected 10/16)

In this Guideline:

Description of the Pest

Looper caterpillars can be distinguished from many other common caterpillars by their distinctive looping movement in which they arch the middle portion of their body to bring the prolegs or hind legs forward to meet the front legs. Loopers are green, usually with a narrow white stripe along each side and several narrow lines down the back. Loopers are smooth-skinned with only a few long bristles down the back; they may grow up to 1.5 inches long. Mature larvae spin silken cocoons and pupate, usually attached to leaves.

Adults are brownish moths with a distinctive silvery figure-8 on the front wings. Eggs are ridged and dome-shaped and usually laid singly on the undersurface of leaves. Loopers may have numerous generations and continue to develop all year long in California with the highest populations usually occurring in fall.


Cabbage loopers are foliage feeders but do not cause economic damage in eggplants.


Cabbage loopers have many natural enemies, and for that reason their presence at low population levels is considered beneficial in an eggplant field. These caterpillars are not usually treated for in eggplants.

Biological Control

Important parasites include the egg parasite Trichogramma pretiosum, the larval parasites Hyposoter exiguae, Copidosoma truncatellum, and Microplitis brassicae, and the parasitic tachinid fly Voria ruralis. A nuclear polyhedrosis virus disease is also important under certain circumstances; the bodies of diseased caterpillars turn into shapeless sacks of dark liquid and can often be spotted hanging from leaves.

Common name Amount per acre** REI‡ PHI‡
(Example trade name)   (hours) (days)

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
  (Intrepid 2F) See label 4 1
  (Confirm) See label 4 7
  (Rimon) 9–12 fl oz 12 1
** See label for dilution rates.
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
1 Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee).



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Eggplant
UC ANR Publication 3475

Insects and Mites

J. L. Aguiar, UC Cooperative Extension, Riverside County
M. J. Jimenez, UC Cooperative Extension, Tulare County
P. B. Goodell, UC IPM, Kearney Agricultural Research and Extension Center, Parlier

Acknowledgments for contributions to Insects and Mites:
R. H. Molinar, UC Cooperative Extension, Fresno County

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