Agriculture: Blueberry Pest Management Guidelines

Light Brown Apple Moth

  • Epiphyas postvittana
  • Description of the Pest

    (View field identification guide)

    Light brown apple moth (LBAM) is an exotic pest native to Australia that has been detected in coastal California from Los Angeles to Sonoma counties. It is a quarantined pest with special requirements regarding movement, inspection and treatment of regulated plant materials. Consult the CDFA website or a county agricultural commissioner's office for local compliance information. Take suspect larvae, preferably alive, or tortricid moths found in light brown apple moth pheromone traps, to the county agricultural commissioner's office for proper identification.

    In both appearance and behavior, the light brown apple moth is similar to other leafroller species in the tortricid family. The mature larvae are pale to medium green with a light yellow-tan head. The first segment behind the head (prothoracic shield) is greenish with no dark markings. Full-grown larvae are about 1/2 to 3/4 inch (10 to 18 mm) long. However, larvae cannot be reliably identified using morphological characters.

    There are many native tortricids that can be confused with this pest. Tortricid moths hold their wings over their abdomens in a bell shape when at rest, andhave protruding mouthparts that resemble a snout. Many moths have oblique markings on the wings.

    Depending on the climate, light brown apple moth may have 2 to 4 generations a year. In its native range it does not survive well at high temperatures, but it does thrive in cooler areas with mild summers, moderate rainfall, and moderate to high humidity. Overwintering larvae do not have a winter resting stage (diapause). They pass the winter as second- to fourth-stage larvae on vegetation surrounding field. Larvae may survive for up to 2 months in the winter without feeding.

    Adult moths emerge after 1 to 3 weeks of pupation and mate soon after emergence. They stay sheltered in the foliage during the day, resting on leaf undersides. Females begin to lay eggs 2 to 3 days after emerging. The eggs are laid on leaves in masses of 20 to 50 (but may contain up to 170 eggs), slightly overlapping each other like fish scales. Egg masses are covered with a greenish transparent coating when newly laid, but the eggs become darker as the embryo develops. Larvae emerge after 1 to 2 weeks and disperse widely on the plant. In spring the first stage larvae move to shoot tips and form nests by webbing together developing leaves. The larvae feed within these shelters. Later in the season, larvae may enter fruit.

    For more information on scouting and field identification, see the video: Scouting and Field Identification of Light Brown Apple Moth in California Nurseries.

    Damage

    Overwintering larvae feed on buds; injured buds may fail to develop. During bloom, larvae feed on flower and fruit clusters. Feeding can also cause direct damage to berries.

    Management

    Research on management of light brown apple moth in California has been limited, due to the quarantines imposed wherever it is found. As a result, most recommendations for California are based on work in grapes from other countries such as Australia and New Zealand, where overwintering sanitation, biological control, and selective insecticides are the primary means of control.

    Biological Control

    General insect predators and several species of spiders can reduce leafroller numbers by feeding on eggs or larvae. High mortality has been reported during the initial dispersal of the newly hatched larvae. Several parasitic wasps, Meteorus sp. in particular, have been recorded parasitizing light brown apple moth in California.

    Cultural Control

    In grapes, sanitation of mummy clusters in the dormant season can help reduce the number of overwintering leafrollers. However, the value of sanitation in blueberries is unknown.

    Organically Acceptable Methods

    Cultural control and sprays of Bacillus thuringiensis and the Entrust formulation of spinosadare acceptable for use on organically certified crops.

    Monitoring and Treatment Decisions

    The most efficient and reliable method for monitoring the presence of moths is with the use of light brown apple moth pheromone traps, using commercially available lures.

    In early spring, monitor shoots for webbing of leaves and larvae inside their nests. Look for rolled leaves that appear glued to shoots. Beginning at bloom, monitor fruit for webbing and larvae. Treatment thresholds are not yet established.

    Common name Amount per acre REI‡ PHI‡
    (Example trade name)   (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.
     
    A. METHOXYFENOZIDE
      (Intrepid 2F) 10–16 fl oz 4 7
      MODE-OF-ACTION GROUP NUMBER1: 18
     
    B. BACILLUS THURINGIENSIS ssp. KURSTAKI#
      (various products) Label rates 4 0
      MODE-OF-ACTION GROUP NUMBER1: 11A
      COMMENTS: Most effective on young larvae. Check with certifier to determine which products are organically acceptable.
     
    C. SPINOSAD
      (Entrust)# 1.25–2 oz 4 3
      MODE-OF-ACTION GROUP NUMBER1: 5
      COMMENTS: Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
     
    D. SPINETORAM
      (Delegate WG) 3–6 oz 4 3
      MODE-OF-ACTION GROUP NUMBER1: 5
      COMMENTS: Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
    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 the two intervals is the minimum time that must elapse before harvest.
    # Acceptable for use on organically grown produce.
    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).
    Text Updated: 12/18
    Treatment Table Updated: 12/18