|scientific name Argyresthia conjugella |
common name Apple Fruit Moth
This species is found mainly in montane regions with mountain ash or apple.
There is a single brood per year, and adults appear in July or earlier (Forbes, 1923: 347).
"Wingspan 10-14 mm. Palpi, face, and head yellowish-white; frons pale brassy; antennae annulated with dark brown and pale ochreous, scrape ochreous; labial palpus ochreous, sometimes brownish. Thorax yellowish-white, sometimes deep purplish-brown anteriorly; tegula deep purplish brown. Forewings dark purplish-brown with dorsal part to tornus white; on the middle of the dorsal edge is an outwardly oblique blackish-brown streak, which lose itself in the dark costal part. Costal edge is strigulated with yellowish white, and shortly before apex is a larger white costal dash. Apical cilia blackish brown; dorsal cilia ochreous fuscous. Hindwing grayish fuscous. Legs brownish ochreous, foreleg deep brown above. Abdomen grayish fuscous" (Busck 1907: 17-18; Emmet et al 1996: 84-85).
Forbes (1923: 347) mentions, "A. belangerella, a closely related taxon, might be only a variety of this species".
This species can be distinguished by the complete absence of golden color on wings, and its special status as a pest of apple and mountain ash, a feature not shared by other Argyresthia in Alberta.
Eggs are oval and slightly flattened, with a deeply pitted surface, and a yellowish or greenish white color. These are laid on unripe fruit of mountain ash (Sorbus aucuparia) or apple (Malus spp.) in June or July. They hatch in two weeks (6-7 days in Japan). In continental Europe they are also laid on cultivated fruit trees (Emmet et al 1996: 84-85). The fully fed larva is 7 mm long, and has a pale brown head, prothoracic and anal plates. Its whitish yellow body turns pink when the larva is full-grown. After hatching, the larva bores into the fruit, eating it out and, on mountain ash, moving to another berry if necessary. Tenanted berries redden prematurely and are often spun together. The larva can be found from June to August. It takes about six weeks for the larva to become full-grown; it then descends to the ground on a silken thread (Emmet et al 1996: 84-85). In Japan, the time spent in the fruit is about 50 days. After leaving the fruit, the larva spins the cocoon, which is normally found in the earth (Moriuti, 1977). The pupa is brown, and is formed in a dense silken cocoon within a second open-network cocoon just beneath the surface of the ground, or under bark. The species overwinters in this stage, from September to May (Emmet et al 1996: 84-85). For further detailed description of larva/pupa/adult characters, see Moriuti (1977: 267-270).
Not of concern.
The principal hosts of the larva are mountain ash (also called rowan, Sorbus aucuparia) and apple (Malus spp.
In Canada it is recorded from British Columbia, Alberta (Edmonton, Lac La Biche) and Saskatchewan (vic. Big River), and probably exists in Manitoba (Pohl et al., in prep.). In US it is recorded form New York (Mt. Marcy, Trenton Falls) and California (Fieldbrook) (Busck, 1907: 18). Widespread in Europe, Asia and North America. The species was first introduced from Europe to North America in 1897 (British Columbia) (Covell 1984, cf. Pohl et al., in prep.).
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