How to Manage Pests

UC Pest Management Guidelines


Codling Moth

Scientific Name: Cydia pomonella

(Reviewed 6/06, updated 4/09)

In this Guideline:


Larvae are white to pinkish caterpillars with brown to black heads. Adult moths have gray wings with a copper spot on each wing tip. Mature larvae overwinter in silken cells under loose bark on the tree, and moths emerge from March to May. Adults mate and lay eggs; larvae feed on small fruit. A second generation appears in June and often a third one in August, depending on temperatures.


Fruit feeding by codling moth is generally not a problem but can damage fruit in some orchards. Codling moth larvae usually tunnel all the way to the pits of fruit; extrusions of frass or excrement are often found at the entrance of the larval tunnels.


Occasionally codling moth is a pest in prunes in a few locations in the Sacramento Valley. A single treatment timed using pheromone traps and degree-days should be all that is needed at these sites.

Biological Control

An important egg and larval parasite is the braconid wasp Ascogaster quadridentata.

Cultural Control

Remove abandoned or unsprayed apple, pear, plum, apricot, and walnut trees near the prune orchard.

Monitoring and Treatment Decisions   Sunset temperatures

Pheromone traps, degree-days (DD), and twilight temperatures are used to monitor codling moth activity. Place traps in the orchard soon after bud break and monitor twice a week to determine first moth emergence. For more information see PHEROMONE TRAPS and record results on a monitoring form (PDF). The biofix is the first date that moths are consistently found in traps and sunset temperatures have reached 62°F. To predict egg hatch, begin accumulating degree-days from the biofix, using a lower threshold of 50°F and an upper threshold of 88°F. Generation time for the first generation of codling moth is 1060 DD, whereas generation time for summer flights averages about 160 DD more.

First generation egg hatch

If a treatment is necessary, time the first spray to the beginning of egg hatch to kill emerging larvae 300 DD after the first biofix for moderate to heavy populations, and 400 to 500 DD for light populations.

Second generation egg hatch

Use pheromone trap catches to detect an increase in flight activity around 1060 DD from the first biofix, which signals the start of the next moth flight. If a second application is necessary, apply it when 250 DD have accumulated from the second biofix.

Fruit damage sample

In mid-July, take a fruit damage sample to assess the overall effectiveness of the current year's IPM program and to determine next year's needs. For more information, see FRUIT EVALUATION AT HARVEST. Record on a monitoring form (PDF) the number of fruit infested by larvae, type of larvae present, whether the damage is surface feeding only or if the larvae penetrated the fruit.

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

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
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. Not all registered pesticides are listed. Always read label of product being used.
  (Imidan) 70WP 4.25 lb 1 lb 3 days 7
  (Sevin) 80S 3 lb 1 lb 12 1
  COMMENTS: May cause increased spider mite problems; not recommended for routine use, especially early in the season.
  (Intrepid) 2F 10–16 fl oz 4 7
  COMMENTS: An insect growth regulator that provides 10 to 18 days of residual protection, depending on the rate of application and nut expansion. Kills young larvae but does not kill adult moths. It is a reduced risk insecticide that has little or no effect on beneficial insects and mites. Only use in orchards with low-to-moderate codling moth populations. Spray coverage is extremely important. Do not apply to large trees unless adequate spray coverage can be verified. Use no less than 100 gal water/acre for ground applications. Sprayer speed should not exceed 1.5 mph. The use of Latron B-1956, CS-7, or similar sticker/spreader is highly recommended. Apply at the beginning of egg hatch, which is earlier than organophosphate or carbamate insecticide timings. It is recommended that methoxyfenozide be applied at 200 DD after the first biofix. Do not apply more than 24 fl oz/acre/application or more than 64 fl oz/acre/season.
  (Asana) 10 oz 2.5 oz 12 14
  COMMENTS: Use promotes mite outbreaks. Low label rates will help reduce the potential for these outbreaks.
  (Warrior) 2.56–5.12 fl oz 24 14
  COMMENTS: Use promotes mite outbreaks. Low label rates will help reduce the potential for these outbreaks.
** 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.
+ 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.
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




[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Prune
UC ANR Publication 3464

Insects and Mites

  • C. Pickel, UC IPM Program, Sutter/Yuba counties
  • F. J. A. Niederholzer, UC Cooperative Extension, Sutter/Yuba counties
  • W. H. Olson, UC Cooperative Extension, Butte County
  • F. G. Zalom, Entomology, UC Davis
  • R. P. Buchner, UC Cooperative Extension, Tehama County
  • W. H. Krueger, UC Cooperative Extension, Glenn County
Acknowledgment for contributions to Insects and Mites:
  • W. O. Reil, UC Cooperative Extension Solano/Yolo counties

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