How to Manage Pests

UC Pest Management Guidelines

Peppers

Omnivorous Leafroller

Scientific name: Platynota stultana

(Reviewed 12/09, updated 5/10)

In this Guideline:


DESCRIPTION OF THE PEST

Omnivorous leafroller adults are small brown moths, about 0.4 inch (10 mm) long, with a snoutlike projection (palpae) that protrudes forward from the head. The portion of the wings nearest the body is a dark rusty brown color; the outer half is light tan. A small rusty brown spot occurs on the front edge of the wing. When at rest, the wings form a bell-shaped pattern. Females lay the small, elliptical eggs in clusters on the smooth surfaces of leaves and stems, overlapping them like fish scales. At hatching, larvae are about 0.06 inch (1.5 mm) long and white with light tan head capsules and thoracic shields. Middle instars are cream-colored and possess dark heads. Mature larvae are about 0.5 inch (12 mm) long and vary in color from cream to a dark brownish green depending on their diet. They have few setae (bristlelike hairs) scattered over the body and possess whitish oval spots along either side of a dark line running down the middle of the dorsum. The head capsule and thoracic shield of mature larvae is brown. When disturbed, larvae retreat into their nests or wiggle vigorously and drop to the ground on a silk thread.

DAMAGE

This insect feeds on a wide variety of weeds and crops. The larvae build a nest by tying leaves together with silk webbing and remain inside this nest while feeding on the surface of the leaves. When leaves lie over a fruit, or if two fruit are touching, the larva will nest between the surfaces and feed on the fruit, causing substantial scarring. Larvae do not burrow into the fruit.

MANAGEMENT

Regular field monitoring will help to detect potential problems with this pest. Weed control and site location play an important role in preventing infestations of omnivorous leafroller. Treatments may occasionally be necessary.

Cultural Control

Early weed control in the area can help to reduce the population; however, the moths can fly for several miles. Avoid planting peppers near alfalfa or sugarbeet as these are good hosts.

Organically Acceptable Methods

Cultural controls and sprays of Bacillus thuringiensis or the Entrust formulation of spinosad are acceptable for used on organically certified produce.

Monitoring and Treatment Decisions

Inspect plants periodically during the growing season in several areas of the field for signs of leaves webbed together. Pay particular attention to weedy areas or locations near other susceptible crops. If nearby alfalfa or sugarbeet fields have been harvested, increase the intensity of the inspection. However, no treatment thresholds have been established.

Good coverage with the spray is critical for control because the larvae are difficult to reach within the folded leaves.

Common name Amount per acre** R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
The following materials are listed in order of usefulness in an IPM program. When choosing a pesticide, consider information relating to impact on natural enemies and pollinators and environmental impact. Not all registered pesticides are listed. Always read the label of the product being used.
 
A. METHOXYFENOZIDE
  (Intrepid 2F) Label rates 4 1
  MODE-OF-ACTION GROUP NUMBER1: 18
  COMMENTS: An insect growth regulator. Apply at the beginning of egg hatch. Pheromone traps can be used to detect moth flight. When traps indicate a flight is occurring, monitor plants for eggs and treat when they appear. Do not apply more than 16 fl oz/acre per application or 64 fl oz/acre per season.
 
B. SPINETORAM
  (Radiant SC) 5–10 fl oz 4 1
  MODE-OF-ACTION GROUP NUMBER1: 5
  COMMENTS: Is more efficacious and has longer residual activity than spinosad.
 
C. SPINOSAD
  (Entrust)# 1.25–2.5 oz 4 1
  (Success) 4–8 oz 4 1
  MODE-OF-ACTION GROUP NUMBER1: 5
  COMMENTS: Use higher rate for larger worms and heavy infestations. Best control is achieved when aimed at newly hatched larvae and coverage is thorough. Can remain toxic to larval stages (especially syrphid fly) for 5-7 days after treatment. Do not exceed 29 fl oz of Success or 9 oz of Entrust/acre per crop.
 
D. BACILLUS THURINGIENSIS ssp. AIZAWAI#
  (various products) Label rates 4 0
  MODE-OF-ACTION GROUP NUMBER1: 11
  COMMENTS: Must be consumed by the larva to be effective. Coverage is critical for controlling this pest, especially between and under leaves and where leaves touch the fruit. Control is most effective against newly hatched worms.
 
E. METHOMYL*
  (Lannate SP) 0.25–0.5 lb 48 3
  (Lannate LV) 0.75–1.5 pt 48 3
  MODE-OF-ACTION GROUP NUMBER1: 1A
  COMMENTS: Do not use if psyllids are present.
 
F. ESFENVALERATE*
  (Asana XL) 5.8–9.6 fl oz. 12 7
  MODE-OF-ACTION GROUP NUMBER1: 3
  COMMENTS: If leafminers are present in the pepper crop, use of this product should be limited to late in the season to minimize negative impacts on biological control.
 
G. CRYOLITE
  (Kryocide) 8–12 lb 12 14
  MODE-OF-ACTION GROUP NUMBER1: un
 
** See label for dilution rates.
+ 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 www.irac-online.org.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Peppers
UC ANR Publication 3460

Insects and Mites

E. T. Natwick, UC Cooperative Extension, Imperial County
J. T. Trumble, Entomology, UC Riverside
Jose Aguiar, UC Cooperative Extension, Riverside County
Acknowledgment for contributions to Insects and Mites:
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
R. L. Coviello, UC Cooperative Extension, Fresno County
C. G. Summers, Kearney Agricultural Center, Parlier
W. E. Chaney, UC Cooperative Extension, Monterey County
C. F. Fouche, UC Cooperative Extension, San Joaquin County

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