How to Manage Pests

UC Pest Management Guidelines



Scientific names:
Cabbage looper: Trichoplusia ni
Alfalfa looper: Autographa californica

(Reviewed 1/07, updated 6/09, pesticides updated 5/15)

In this Guideline:


Loopers arch their backs as they crawl. Cabbage loopers usually have a narrow, white stripe along each side and several narrow lines down the back. Eggs are dome-shaped, and laid on the undersurfaces of older leaves. Adult moths have brown, mottled forewings marked in the center with a small silver figure 8.


Young larvae feed primarily on the undersides of lower leaves, skeletonizing them. High populations can damage seedlings severely enough to kill them or slow growth enough to inhibit uniform maturing of the crop. Older larvae may burrow into the head from the top.


Loopers are primarily an early season pest in inland desert growing areas.

Biological Control
Loopers have many natural enemies that often keep populations below economic thresholds. Maximize the use of these natural enemies by limiting treatments, especially between thinning and heading.

Organically Acceptable Methods
Biological control and sprays of Bacillus thuringiensis are acceptable for use on organically certified crops.

Monitoring and Management Decisions
Look for signs of looper feeding: plants with holes in outer leaves, feces, caterpillars feeding on edge of hole. Check fields twice a week once seedlings emerge.

Treat seedlings or small plants if populations of medium-sized to large loopers are large enough to stunt growth. Treat well-established plants only if you find an average of more than one-half larvae per plant. For cabbage looper control, the best time to apply insecticide is in the afternoon.

Common name Amount per acre R.E.I.‡ P.H.I.‡
(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—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.
  (Coragen) 3.5–5.0 fl oz 4 3
  COMMENTS: Do not make more than 4 applications/acre per crop and do not apply more than 15.4 fl oz Coragen (0.2 lbs a.i.)/acre per crop.
  (Radiant SC) 6–8 fl oz 4 See label
  COMMENTS: For resistance management, do not make more than two consecutive applications of group 5 insecticides.
  (various products) Label rates 4 0
  COMMENTS: Apply when armyworms are small. Not harmful to natural enemies.
  (Dimilin 2L) 8-16 oz 12 1
  COMMENTS: Use allowed under 24(c) regulation.
Restricted entry interval (R.E.I.)is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) 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 the 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). For additional information, see their Web site at
# Acceptable for use on organically grown produce.
* Permit required from county agricultural commissioner for purchase or use.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Artichoke
UC ANR Publication 3434

Insects and Mites

M. A. Bari, Artichoke Research Foundation, Salinas
E. T. Natwick, UC Cooperative Extension, Imperial County

Acknowledgment for contributions to Insects and Mites:
W. E. Chaney, UC Cooperative Extension, Monterey County
W. L. Schrader, UC Cooperative Extension, San Diego County
L. Handel and T. K. Shannon, Kleen Globe, Inc., Castroville, CA

Top of page

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2017 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   Contact webmaster.