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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Cabbage looper larva.

Dry Beans

Loopers

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

(Reviewed 8/07, updated 8/07)

In this Guideline:

DESCRIPTION OF THE PESTS

Alfalfa looper and cabbage looper larvae are green with three pairs of true legs up front and two pairs of robust, unjointed prolegs on the abdomen (back portion of the body). A distinguishing characteristic is that the larvae arch their backs when they crawl. Adults moths have dark brown, mottled forewings with a characteristic figure-eight marking in the center.

DAMAGE

Loopers may occur at any time during the growing season. Infestations early in the season on seedling plants may result in damage to cotyledons, new leaves, and terminal buds. Looper eggs are deposited singly, usually on the underside of younger leaves, and the larvae feed on larger, more mature leaves.

MANAGEMENT

Biological Control
Loopers have many natural enemies that frequently keep them below economic levels, unless they are killed by insecticide applications applied for other pests. Important parasitic wasps include the tiny egg parasite, Trichogramma pretiosum, and four wasps that attack the caterpillars: Hyposoter exiguae, Copidosoma truncatellum, Microplitis brassicae, and Cortesia medicaginis (alfalfa looper only). The tachinid fly, Voria ruralis, also attacks the caterpillar. In some areas, the nuclear polyhedrosis virus, an important biological control agent, occurs naturally in fields and kills loopers that it infects.

Organically Acceptable Methods
Biological control and sprays of Bacillus thuringiensis and the Entrust formulation of spinosad are organically acceptable.

Monitoring and Treatment Decisions
Specific treatment thresholds have not been established for these foliage feeders. Late season infestations are insignificant. If damaging numbers are encountered mid-season when excessive foliage loss may reduce crop production, a treatment may be warranted.

Common name Amount/Acre** R.E.I.+ P.H.I.+
(trade name)   (hours) (days)
When choosing a pesticide, consider information relating to the impact on natural enemies and honey bees and environmental impact.
 
A. BACILLUS THURINGIENSIS ssp. AIZAWAI#
  (various products) Label rates 4 0
  MODE OF ACTION GROUP NUMBER1: 11.B1
  COMMENTS: This material does not destroy natural enemies of corn earworm. Control is maximized by thorough coverage and by making applications when larvae are small.
 
B. SPINOSAD
  (Entrust)# 1.25–2 oz 4 28
  (Success) 4–6 fl oz 4 28
  MODE OF ACTION GROUP NUMBER1: 5
  COMMENTS: Do not apply more than 12 oz/acre/season of Success or 3.75 oz/acre/season of Entrust. For blackeyes, be sure to apply with an oil.
 
C. CARBARYL*
  (Sevin) 80S 1.25 lb 12 see comments
  (Sevin) XLR Plus 1 qt 12 see comments
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: May result in outbreak of spider mites. Do not use on lentils in California. XLR Plus formulation is the least toxic to honey bees when direct application to bees is avoided and the spray residues have dried. Apply from late evening to early morning when bees are not foraging. Do not apply within 14 days of grazing or harvest for forage, within 3 days of harvest of fresh beans or peas, and within 21 days of harvest of dried beans, peas, seed, or hay.
 
D. ACEPHATE
  (Orthene) 75 SP 0.67 lb 24 14
  MODE OF ACTION GROUP NUMBER1: 1B
  COMMENTS: Use of product may result in mite outbreak. Highly toxic to honey bees; do not apply when bees are present.
 
E. METHOMYL*
  (Lannate SP) 0.5–1 lb 48 14
  MODE OF ACTION GROUP NUMBER1: 1A
  COMMENTS: Highly toxic to honey bees; do not apply when bees are present. Do not apply more than 4.5 lb a.i./acre/crop.
 
F. LAMBDA-CYHALOTHRIN*
  (Warrior with Zeon) 3.84 oz 24 see comments
  MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: May cause outbreaks of mites. Preharvest interval (P.H.I.) is 7 days for succulent shelled or edible podded crops and 21 days for dried shelled crops.
 
G. ZETA-CYPERMETHRIN*
  (Mustang) 4.3 oz 12 see comments
  MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: May cause outbreaks of mites. Preharvest interval (P.H.I.) is 1 day for succulent shelled or edible podded crops and 21 days for dried shelled crops.
 
 
**  Mix with sufficient water to obtain full coverage.
+ 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.
* Permit required from county agricultural commissioner for purchase or use.
# Acceptable for use on organically grown produce.
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). For additional information, see their Web site at http://www.irac-online.org/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Dry Beans
UC ANR Publication 3446
Insects and Mites
L. D. Godfrey, Entomology, UC Davis
R. F. Long, UC Cooperative Extension, Yolo Co.

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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