Light brown apple moth
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 Epiphyas postvittana
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| Epiphyas postvittana Walker, 1863 |
The light brown apple moth (Epiphyas postvittana) is a leafroller moth belonging to the lepidopteran family Tortricidae.
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[edit] Identification
[edit] Adult moths
Light brown apple moth adults are variable in colour and may be confused with other leafroller moths. Typical males have a forewing length of 6–10 mm with a light brown area at the base distinguishable from a much darker, red-brown area at the tip. The latter may be absent, the moth appearing uniformly light brown, as in the females, with only slightly darker oblique markings distinguishing the area at the tip of the wing. Females have a forewing length of 7–13 mm.
[edit] Larvae
Larvae are not easily distinguished from the larvae of other tortricid leafrollers. The first larval instar has a dark brown head; all other instars have a light fawn head and prothoracic plate. Overwintering larvae are darker. First instar larvae are approximately 1.6 mm long, and final instar larvae range from 10–18 mm in length. The body of a mature larva is medium green with a darker green central stripe and two side stripes.
[edit] Distribution
The light brown apple moth is a native insect of Australia. It has been introduced and now occurs in New Caledonia, the British Isles, Hawaii, Western Australia and New Zealand.
[edit] Life cycle
Light brown apple moth passes through three generations annually with a partial fourth generation in some years, and has no winter resting stage. There is considerable overlap in the generations. In warmer areas four generations are completed annually, with major flight periods occurring during September-October, December-January, February–March, and April–May. In cooler climates the number of complete generations may be reduced to two.
Eggs are laid in clusters of 3–150 on leaves or fruit. Adults produced by the overwintering larval generation emerge during October and November. These give rise to the first summer generation, in which final instar larvae mature between January and mid February. Second generation larvae reach maturity during March and April, and the adults from this generation provide third generation eggs. Normally, the rate of larval development is slowed considerably during the winter; thus the majority of larvae over-winter in the prolonged early juvenile phases of the second third, and fourth instars. During this period they normally feed on herbaceous plants. Re-invasion of apple trees takes place during October-December, when moths of the third generation start laying eggs again on the apple leaves
[edit] Sex pheromone
Females release a specific blend of sex pheromone to attract males. The blend is a mixture of two compounds (E)-11-tetradedecen-1-yl acetate, comprising 95% of the mixture and (E,E)-9,11-tetradecadien-1-yl acetate comprising the remaining 5% (Bellas et al., 1983).
[edit] Diet and damage
The insect is highly polyphagous and the larvae attack numerous horticultural crops in Australia and New Zealand. 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 attacks nearly all types of fruit crops, ornamentals, vegetables, glasshouse crops, and occasionally young pine seedlings.
The larvae cause 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.
Superficial fruit damage is common in apple varieties which form compact fruit clusters. 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
[edit] Control
The species has been classified as a noxious insect in the United States and Canada, leading to restrictions on produce from counties with substantial populations. Typical orchard control of the insect commonly involves IPM regimes using a variety of methods such as insecticide applications, biological control and occasionally mating disruption. Pheromone lures are often used to assess and monitor populations of moths in specific areas.
[edit] References
- Bellas, T.E., Bartell, R.J. and Hill, A. (1983) Identification of two components of the sex pheromone of the moth, Epiphyas postvittana (Lepidoptera, Tortricidae) Journal of Chemical Ecology 9, 503-511.
- Thomas, W. P. (1989) Epiphyas postvittana (Walker), light brown apple moth (Lepidoptera: Tortricidae). In: A review of biological control of invertebrate pests & weeds in New Zealand (Cameron, P. J., Hill, R. L., Bain, J. and Thomas, W. P., eds), pp. 187-195. CAB International, London.
- Wearing, C. H., Thomas, W. P., Dugdale, J. S. and Danthanarayana, W. (1991) Tortricid pests of pome and stone fruits, Australian and New Zealand species. In: Tortricid pests, their biology, natural enemies and control (Van der Geest, L. P. S. and Evenhuis, H. H., eds), pp. 453-472. Elsevier, Amsterdam.
