How to Manage Pests

UC Pest Management Guidelines

Adult navel orangeworm.

Pomegranate

Navel Orangeworm and Carob Moth

Scientific names:
Navel orangeworm: Amyelois transitella
Carob moth: Ectomyelois ceratoniae

(Reviewed 10/13, updated 10/13)

In this Guideline:


Description of the pests

Navel orangeworm and carob moth have similar behavior and look almost identical. Adult moths have a snoutlike projection at the front of the head. Moths can have silver and black forewings and legs or wings can be cinnamon brown and black.

About two nights after emergence, females begin laying eggs next to wounds or rotten spots in the fruit. Newly hatched larvae are reddish orange and later vary from milky white to pink with a reddish brown head capsule. Distinguish both navel orangeworm and carob moth larvae from similar looking caterpillars such as oriental fruit moth by looking for a pair of crescent-shaped markings on the second segment behind their head. Pupae are light to dark brown, encased in a woven cocoon in the fruit. There are three to four adult flight periods per year. The larvae overwinter in old fruit, either in trees or on the ground.

The pupal stage is the best time to differentiate the carob moth from the navel orangeworm. Carob moth pupae have a raised dark ridge near the head and two short spines on each abdominal segment, which are lacking in the navel orangeworm.

Damage

Navel orangeworm and carob moth rarely attack healthy pomegranate fruit, but if numbers are high, such as for orchards near almonds or pistachios, damage can be serious. So far damage has only been reported in early varieties such as Early Foothill. In adjacent Wonderful orchards only occasional damage has been noted.

Moths prefer to lay eggs on damaged fruit and as larvae typically enter through cracks, rotten spots, or wounds caused by other pests such as omnivorous leafroller. However, larvae hatching from eggs laid on the seam where two calyx petals touch have been observed entering the calyx. Feeding inside the calyx sometimes leads to rot.

Navel orangeworm and carob moth produce more silk and frass than leafrollers and may be found with more than one worm in the same feeding tunnel. Neither navel orangeworm nor carob moth is common in pomegranates.

Management

Remove unharvested fruit from the trees and disc into the soil to reduce overwintering moth numbers and prevent populations from establishing.

Monitor flights with pheromone lures. Egg traps can also be used placed out in the orchard the first week of April.

  1. Use black egg traps baited with almond presscake filled half- to three-quarters-full. Change bait every 4 weeks. Keep presscake dry; if it gets wet, lumpy, or moldy replace it.
  2. Place 1 trap per every 10 acres, for at least 4 traps per orchard. Choose trees that are at least 5 trees in from the edge of the orchard. Hang traps at head height on the north side of trees.
  3. Monitor traps, counting and recording egg numbers. Remove eggs as you monitor.

In orchards with high moth numbers or a history of damage, apply an insecticide during egg hatch before fruit ripening. Use an insecticide with a long residual during hatching, activity against adult moths, or both.

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

  Calculate impact of pesticide on air quality
 
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to 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.
 
A. CHLORANTRANILIPROLE
  (Altacor) 3–4.5 oz 4 1
  MODE-OF-ACTION GROUP NUMBER1: 28
 
B. SPINETORAM
  (Delegate WG) 4–7 oz 4 1
  MODE-OF-ACTION GROUP NUMBER1: 5
  COMMENTS: Highly toxic to bees. Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
 
C. METHOXYFENOZIDE
  (Intrepid 2F) 8–16 fl oz 4 7
  MODE-OF-ACTION GROUP NUMBER1: 18
 
D. SPINOSAD
  (Entrust#) 1.25–2.5 oz
(0.45–0.83 oz/100 gal)
4 7
  MODE-OF-ACTION GROUP NUMBER1: 5
  COMMENTS: Highly toxic to bees. Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
 
E. BACILLUS THURINGIENSIS ssp. KURSTAKI#
  (various products) Label rates 4 0
  MODE-OF-ACTION GROUP NUMBER1: 11.B2
  COMMENTS: Least harmful to natural enemies. Bacillus thuringiensis is a stomach poison and must be consumed. Must be applied when larvae are small. A second or third treatment may be required. Most effective if applied when weather forecasts predict 3 to 4 days of warm, dry weather. Larvae are more active and feed more in warm weather than in cooler or rainy weather.
 
F. METHOMYL*
  (Lannate SP) 1 lb 48 14
  MODE-OF-ACTION GROUP NUMBER1: 1A
  COMMENTS: Disruptive to natural enemies of mealybugs, caterpillars, soft scales, aphids, and other pests. Use of this material may result in outbreaks of these pests.
 
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 R.E.I. exceeds the P.H.I. The longer of two intervals is the minimum time that must elapse before harvest.
# 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/.
* Permit required from county agricultural commissioner for purchase or use.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Pomegranate
UC ANR Publication 3474

Insects and mites

  • E. E. Grafton-Cardwell, Entomology, UC Riverside and Kearney Agricultural Center, Parlier
  • D. Carroll, Bio Ag Services, Inc., Fresno
  • W. J. Bentley, UC IPM Program (emeritus), Kearney Agricultural Center, Parlier
  • D. R. Haviland, UC Cooperative Extension, Kern County
  • V. Walton, Horticulture, Oregon State University (filbertworm)

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