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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Saltmarsh caterpillar adult.

Carrot

Saltmarsh Caterpillar

Scientific Name: Estigmene acrea

(Reviewed 10/05, updated 10/05)

In this Guideline:

DESCRIPTION OF THE PEST

Saltmarsh caterpillar larvae are hairy and gray when first hatched, then darken to yellow, brownish, or almost black with yellow lines. They are covered with reddish or black hairs, and can be up to 2 inches long when fully grown. Eggs are spherical, whitish, somewhat flattened, about 0.03 inch in diameter, and found in clusters on the undersurface of leaves.

DAMAGE

In the southern San Joaquin Valley saltmarsh caterpillars are occasional pests that feed on foliage. They are primarily a problem in fall when neighboring cotton fields are defoliated.

MANAGEMENT

Cultural Control
Ditch or trench around the edges of fields that border cotton.

Organically Acceptable Methods
Cultural control and sprays of the Entrust formulation of spinosad are acceptable for use on organically grown produce.

Monitoring and Treatment Decisions
In fall, if saltmarsh caterpillars are migrating into carrots, a treatment may be necessary.

Common name Amount/Acre** P.H.I.+
(trade name)   (days)
When choosing a pesticide, consider information relating to water quality and impact on natural enemies and bees.
       
A. SPINOSAD    
  (Entrust)#
1–2 fl oz
3
  MODE OF ACTION: A microbial (Group 5)1 insecticide.
  COMMENTS: Do not apply more than 7 oz of Entrust/acre/crop or more than 4 applications/calendar year. Additional applications must be at least 5 days apart. Use allowed under a supplemental label.
       
B. CARBARYL*    
  (Sevin) 80S
1.25–2.5 lb
7
  MODE OF ACTION: A carbamate (Group 1A)1 insecticide.
  COMMENTS: Ground or air application.
   
** See label for dilution rates.  
+ Preharvest interval. Do not apply within this many days of harvest.  
1 Modes of action are important in preventing the development of resistance to pesticides. 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. 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 is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
# Acceptable for use on organically grown produce.  
* Permit required from county agricultural commissioner for purchase or use.  

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Carrot
UC ANR Publication 3438
Insects
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
W. E. Chaney, UC Cooperative Extension, Monterey Co.
E. T. Natwick, UC Cooperative Extension, Imperial Co.
D. R. Haviland, UC IPM Program, Kern Co.

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Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2005 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 How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/r102300911.html revised: October 28, 2005. Contact webmaster.