Navel orangeworm

Have you seen navel orangeworm symptoms?

In Queensland, the navel orangeworm (Amyelois transitella) is listed as prohibited matter under the Biosecurity Act 2014.

Be on the lookout for symptoms and report them to Biosecurity Queensland.

Early detection and reporting are the key elements in controlling the pest.

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General information

Navel orangeworm (Amyelois transitella) is an exotic pest that feeds on a variety of fruit and nuts, including citrus. While the insect is a serious pest of some nut crops like almonds and pistachios, it also grazes on citrus fruit, causing surface scarring that allows decay-causing organisms to enter the fruit. This reduces fruit quality and causes fruit drop, reducing economic return.

Overview

Symptoms

Check for caterpillar frass near wounds in the fruit. Navel orangeworm larvae scavenge in splits and wounds of citrus fruit (such as naval oranges) and feed in or near the core. The larvae can overwinter in rotting or mummified fruit left on trees.

Appearance

Adults

  • Adult moths are about 9-11 mm long and greyish-brown.
  • Their wings have silver-grey markings.
  • The moths have short, dark projections from the front of the head.

Larvae

The larvae are white to pink with a dark reddish-brown head.
  • They have a distinctive pair of crescent-shaped markings on the second segment behind the head.
  • Larvae are tiny when they first hatch, but as they develop they can grow up to 13-19 mm long.
  • Pupae

    • Pupae are about 7-12 mm long and dark brown.

    Eggs

    • Navel orangeworm eggs are tiny, oval and flattened, with ridge-like marks.
    • Initially, eggs are white, but turn pink, then reddish-brown before hatching.
    • They are laid in the navel end of injured oranges.
    Hosts

    Navel orangeworm feeds on a variety of fruit and nuts.

    It is a serious pest of nut crops such as English walnuts, pistachios and almonds, but also feeds on citrus, dates, figs, apples, pears and stone fruit.

    Distribution

    Navel orangeworms occur in the United States, Canada and Central America (Caribbean and Cost Rica). It not known to occur in Australia.

    Spread of pest

    Long-distance spread occurs by movement of plant material infested with the larvae and pupae. The Australian Quarantine and Inspection Service closely regulates approved imports of host plants (whole or parts) and monitors for illegal plant movement.

    Management and quarantine

    Navel orangeworm is restricted matter under the Biosecurity Act 2014. If found it must be reported. There are simple steps you can take to protect your farm:

    • Be aware of navel orangeworms.
    • Do not illegally import fruit.
    • Keep your farm clean. Use good hygiene practices to manage discarded fruit under trees. Remove damaged or mummified fruit from trees.
    • Check your crop. Make sure you and your farm workers are familiar with the signs of navel orangeworm infested fruit.
    • Regularly check your orchard and report any unusual or unfamiliar pests.
    Reference and acknowledgement

    Navel orangeworm fact sheet (PDF, 365.5KB)

    Andrew Beattie (University of Western Sydney) and Ceri Pearce (Biosecurity Queensland, Department of Agriculture and Fisheries).

    Last updated 11 May 2017