Author: (Herrich-Schäffer, 1851)
Adult: 12-14 mm wingspan; basal third of forewing greyish fuscous and distal two-thirds dark purplish fuscous except for four pairs of well-defined interspaces between blackish costal strigulae; dorsal blotch well-defined; fasciae indeterminate; hindwing blackish fuscous.
Egg: deposited on young cones.
Larva: 10-12 mm long when fully grown; head dark brown, without lateral pigmentation or markings; prothoracic plate dark brown, small, with median sulcus distinct; abdomen translucent, yellowish grey to brownish white; anal plate small, weakly sclerotized and dark-flecked.
Pupa: inside a web on the soil, or in rotten wood.
Cydia illutana adult 1
Cydia illutana adult 2
External characters: 12-14 mm wingspan. Labial palpus and frons of head light greyish fuscous; crown, thorax, patagium and tegula deep greyish fuscous with weak purplish sheen. Forewing ground colour white overlaid in basal third with greyish fuscous, slightly olivaceous, and in distal two-thirds with dark purplish fuscous except for four pairs of well-defined interspaces between blackish costal strigulae, some of the interspaces emitting outward-oblique, weakly metallic, plumbeous or bluish striae reaching to about one-third across wing, and a slender, nearly erect, slightly falcate mediodorsal blotch reaching nearly to middle and cleft or indented on dorsum; also an indication of a small white dot on termen a little below apex; fasciae indeterminate; ocellus moderately well defined, edged laterally with weakly metallic plumbeous or bluish striae, the inner one nearly extending to the end of the stria arising from the post median pair of costal strigulae; ocellus marked with four or five more or less evenly spaced black dashes traversing it from outer (distal) to inner margin but sometimes fractured; a thinly distributed irroration of yellow-tipped scales in and around ocellus; cilia concolorous with wing basally, with a black sub-basal line, and cream-brown apically. Hindwing blackish fuscous; cilia light grey, paler or whitish apically, with a fuscous sub-basal line.
male genitalia Cydia illutana
Genitalia: Aedeagus with a series of 11 (possibly variable in number) short cornuti, forming a straight chain with the tip of the hind one overlapping the base of the one in front. Sacculus of valva shallowly convex ventrally.
The species is likely to be confused with Cydia pactolana, but the genitalia of the male have a characteristic imbricate chain-like arrangement of the cornuti in the aedeagus, compared with the slightly larger and loosely compacted cornuti of Cydia pactolana, and the sacculus of the valva is shallowly curved (convex) and not angulate and prominent distally as in Cydia pactolana.
External characters: Similar to male
female genitalia Cydia illutana
Genitalia: Ostium small, with lower lip of sterigma (lamella antevaginalis) slightly wrinkled. Ductus bursae with internal sclerites. Median field of 7th sternite demarcated from lateral regions by grooves, these grooves converging anteriorly.
Cydia illutana is an univoltine species. Moths fly in May and June. The females deposit their eggs on young cones in the second half of June. The larvae feed in the cones and bore into the seeds. The excrements are ejected and remain, mixed with resin, attached to the cones. Excrements can also be deposited in the feeding tunnels. The larvae continue to feed in spring after hibernation. Pupation takes place inside a web on the soil, or in rotten wood, in May. Sacchiphantes or Chermes galls may also be attacked in years in which only a few cones are formed (Bogenschütz, 1991).
Abies alba, Picea abies, Picea obovata, Larix decidua Miller, Larix gmelinii, Larix sibirica and Pseudotsuga menziesii.
The feeding inhibits the maturing of the cones and the ejection of the seeds. Seed production is diminished by infestations of this species. Damage may be considerable in Finland and the northern part of Russia, where this species is frequently observed together with Cydia strobilella. Its economic importance, in comparison to that of Cydia strobilella, is in reality small, despite its frequent occurrence (Bogenschütz, 1991).
The species occurs from Western and Central Europe (UK, Netherlands, Austria, Germany, France) northwards into Scandinavia (Denmark, Norway, Sweden and Finland) and ranges eastwards into Russia (Siberia).
E 8E 10-12Ac (Witzgall et al., 1996b)