Light Brown Apple Moth - Diet and Damage

Diet and Damage

The insect is regarded as an herbivorous generalist, and the larvae feed on numerous horticultural crops in Australia and New Zealand, where they have limited natural predators. It is known to feed on 123 dicotyledonous plant species, including 22 Australian natives, belonging to 55 different families. In New Zealand, over 250 host species have been recorded. It feeds on nearly all types of fruit crops, ornamentals, vegetables, glasshouse crops, and occasionally young pine seedlings.

The larvae cause significant damage to foliage and fruit. Early instars feed on tissue beneath the upper epidermis (surface layer) of leaves, while protected under self-constructed silken webs on the undersurface of leaves. Larger larvae migrate from these positions to construct feeding niches between adjacent leaves, between a leaf and a fruit, in the developing bud, or on a single leaf, where the leaf roll develops. The late stage larvae feed on all leaf tissue except main veins, and can often be found tunneling into berry fruits such as strawberries and caneberries.

Superficial fruit damage is common in apple varieties which form compact fruit clusters, though more significant damage may also occur such that crops are no longer commercially viable. Leaves are webbed to the fruit and feeding injury takes place under the protection of the leaf; or larvae spin up between fruits of a cluster. Internal damage to apple, pear, and citrus fruits is less common, but a young larva may enter the interior of an apple or pear fruit through the calyx or beneath the stem of a citrus fruit. Excreta are usually ejected on to the outside of the fruit.

In sharp contrast to most affected regions, the Hawaii Department of Agriculture says the moth "has not been a significant pest in Hawaii" and finds it beneficial in a few cases, because it kills some invasive plants, including gorse and blackberry.

In April 2008, an attorney for the California Department of Agriculture acknowledged in court papers that there were "no documented crop losses in California at this time".