UC IPM Online UC ANR home page UC IPM home page

UC IPM Home

Search

SKIP navigation

Home & garden
Agriculture
Natural environments
Exotic & invasive

Weather data & products
Degree-days
Interactive tools & models

Publications & more
Workshops and events
Training programs
Pesticide information

Grants programs
Funded-project results


 

How to Manage Pests

UC Pest Management Guidelines


Orange tortrix larva.

Plum

Orange Tortrix

Scientific name: Argyrotaenia citrana

(Reviewed 5/06, updated 5/06)

In this Guideline:


DESCRIPTION OF THE PEST

The orange tortrix is only found in coastal areas. Its larvae are light green caterpillars with brown heads; they resemble obliquebanded leafroller caterpillars. When disturbed, the larvae wiggle backwards and drop to the ground on a silken thread. Adults are fawn or gray-colored moths with a darker mottling on the forewings. The orange tortrix overwinters as larvae and there are two to four generations each year in coastal areas.

DAMAGE

Larvae feed on leaves, buds, and the surface of fruit, causing severe damage as well as contamination with their excrement.

MANAGEMENT

Orange tortrix is a cyclical pest. In coastal orchards, natural enemies and treatments for other pests usually keep this pest controlled. In other areas treatment is not needed.

Biological Control
Several parasites and predators attack orange tortrix. Parasites include the wasps Cotesia (Apanteles) aristolidae, Exochus sp., and Hormius basalis and a tachinid fly (Nemorilla pyste). Predators include spiders and brown lacewing larvae (Hemerobius pacificus).

Cultural Control
Remove and dispose of mummy fruit to reduce overwintering orange tortrix. Also, remove weed hosts such as mustard. The use of grass cover crops helps reduce overwintering hosts.

Organically Acceptable Methods
Biological and cultural controls and sprays of Bacillus thuringiensis are organically acceptable controls.

Monitoring and Treatment Decisions
If you suspect orange tortrix is a problem and your orchard is located in coastal areas, sample fruit on a weekly basis for damage beginning in June to determine spray timing. Sample 20 fruit on 15 trees for a total of 300 fruit. Treat if between 1 and 2% damage occurs on fresh market fruit (check with cannery fieldman for damage acceptable for processing fruit).

Take a fruit damage sample at harvest to assess the effectiveness of the current year's IPM program and to determine the needs of next year's program. See FRUIT EVALUATION AT HARVEST. Record results on a monitoring form (100KB, PDF).

Common name Amount to Use** P.H.I.+
(trade name) (conc.) (dilute) (days)

The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, impact on natural enemies and honey bees, and impact of the timing on beneficials. When choosing a pesticide, also consider information relating to environmental impact.
 
A. BACILLUS THURINGIENSIS# ssp. KURSTAKI
  (various products) Label rates 0
  MODE OF ACTION: A microbial (Group 11.B2)1 insecticide.
  COMMENTS: Timing is important because of short residual period. Apply only during warm dry weather to control young actively feeding worms; may need to be applied more than once. Good coverage is essential.
 
B. DIAZINON* 50WP 3 lb 1 lb 21
  DIAZINON* 4EC 3 pt 1 pt 21
  MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
  COMMENTS: Avoid drift and runoff into surface waters. Where plums are grown near waterways, do not use diazinon.
 
 
**  For dilute applications, rate is per 100 gal water to be applied in 300-500 gal water/acre, according to label; for concentrate applications, use 80-100 gal water/acre, or lower if the label allows.
+ Preharvest interval. Do not apply within this many days of harvest.
* Permit required from county agricultural commissioner for purchase or use.
# Acceptable for use on organically grown produce.
—  Not recommended or not on label.
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/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Plum
UC ANR Publication 3462
Insects and Mites
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to the insects and mites section:
R. E. Rice, Kearney Agricultural Center, Parlier

Top of page


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2006 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/r611300711.html revised: May 19, 2006. Contact webmaster.