Agriculture: Prune Pest Management Guidelines

Codling Moth

  • Cydia pomonella
  • Description of the Pest

    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

    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.

    Calculate degree-days for codling moth in prune for your location using the codling moth in prune pest model or degree-day table. To learn more about using degree-days to time insecticide applications, watch the degree-days video. Use the online tool to find your sunset temperature.

    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** REI‡ PHI‡
    (Example trade name) (conc.) (dilute) (hours) (days)
    Not all registered pesticides are listed. 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. Always read the label of the 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.
    * Permit required from county agricultural commissioner for purchase or use.
    ** 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 (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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.
    1 Rotate pesticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B. Mode-of-action group numbers for insecticides and miticides (un=unknown or uncertain mode of action) are assigned by IRAC (Insecticide Resistance Action Committee).

    Important Links

    Text Updated: 04/09
    Treatment Table Updated: 04/09