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Damage (Winter moth)

Foliage and buds are devoured indiscriminately in spring by larvae, which bite holes in developing fruitlets. These either drop prematurely or develop into malformed fruits with corky …

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Recognition (Winter moth)

Adult male Flies at night in winter. Wingspan 22-28 mm, forewings rounded, greyish brown and with darker wavy cross-lines. Adult female Found on tree trunks and branches in winter. Wings reduced to stubs; body 5‑6 mm long, dark brown mottled with greyish …

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Monitoring (Winter moth)

Pre-blossom visual assessment Inspect at least 100 trusses (e.g. 4 on each of 25 trees) per orchard for signs of damage or infestation by winter moth larvae at the green cluster to pink bud growth stage of apple. Inspect trees at the edge of the orchard …

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Chemical control (Winter moth)

Chemical control is the principal means of control in UK orchards. A wide range of insecticides are approved for control of caterpillar pests on apple. The pest is sensitive to insecticides and can be controlled cheaply and effectively. It was common …

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Insecticide resistance (Winter moth)

As winter moth is abundant in woodland and wild places that are not treated with insecticides and which provide the source of infestation for the pest and because the pest has only one generation per annum, the probability of insecticide resistance …

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Cultural control (Winter moth)

Spatial isolation Winter moth is a denizen of woodland trees, especially oak. The pest is much less of a problem in orchards which are isolated from such woodland and larger hedgerows. Grease banding of trunks A band of a recommended grease may be pasted …

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Natural enemies (Winter moth)

Predators Insectivorous birds and many species of polyphagous predatory insects feed occasionally on winter moth larvae. However, their impact on populations of winter moth larvae in orchards is limited. Parasitoids Many species of parasitoid attack the …

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Biological control (Winter moth)

One or more sprays of Bacillus thuringiensis (Bt) before blossom will control winter moth larvae, providing temperatures are high enough for the caterpillars to be feeding actively. The bacteria and the crystal toxin which it produces, have to be ingested …

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