Author: (Doubleday, 1849)
Grey tortrix
Japanese subspecies Cnephasia stephensiana stolidana : Tobacco leaf worm
Species Overview:
Adult: 18-22 mm wingspan; forewings whitish-grey suffused with grey, brownish-grey irregularly edged markings speckled with black; hindwings brownish-grey.
Egg: cream-buff, deposited singly or in small batches on the food plant.
Larva: 15-18 mm long; head variable, light brown marked with dark brown, or entirely brownish black or black; prothoracic plate black, edged anteriorly with grey, a whitish narrow medial sulcus; abdomen shining grey or bluish grey, variable and sometimes darker or lighter, or with a slight greenish tinge; anal plate blackish brown; anal comb absent; thoracic legs black.
Pupa: blackish brown; cremaster spines prominent, curved; caudal bristles filamentous; no distinct transverse ridge ventrad of the cremaster spines [cremaster pupa C. stephensiana ].
Taxonomic Description:
Male:
Cnephasia stephensiana adult
Cnephasia stephensiana male
Cnephasia stephensiana males
External characters: Antenna very shortly ciliate. Costal margin of forewing slightly arced, apex rounded, termen oblique. Ground colour greyish white diffusely irrorate with grey; markings brownish grey irregularly edged and speckled with black; sub-basal fascia terminating well above dorsum; median fascia with inner margin irregularly dentate, strongly edged with black, outer margin diffuse, deeply excavated above and below middle; costal and terminal markings diffuse and ill-defined. Hindwing brownish grey (Bradley et al., 1973).
male genitalia C. stephensiana
Genitalia: Sacculus attached to valva to about half of its length. The separate tip of sacculus curved, lying on the valva. Valva elongate, about equally wide on the whole of its length. Uncus long; socii broad; terminal plate of gnathos broad. Aedeagus fairly broad, acuminate terminally
Female:
Cnephasia stephensiana female
Cnephasia stephensiana females
External characters: Similar to male; forewing comparatively broader, hindwing darker.
female gen. C. stephensiana
Genitalia: Lamella antevaginalis broad, concave in the middle of its distal edge; antrum more sclerotized than ductus, slightly shorter than ductus.
Variation:
The typical form of this species shows considerable minor variation in the ground colour and markings of the forewing. Melanistic forms occur in which the ground colour of the forewing is dark fuscous and the markings are inconspicuous; light, almost unicolorous white specimens also occur. The form octomaculana Curtis has the forewing ground colour almost clear white, the markings contrasting and well defined. In this form the median fascia is often weak or interrupted a little above the dorsum (Bradley et al., 1973).
Taxonomic notes:
Four subspecies are recognized:
Cnephasia stephensiana stephensiana (Doubleday) (Europe to Asia Minor and mountains of Turkmenistan)
Cnephasia stephensiana atlantis Filipjev (Morocco)
Cnephasia stephensiana anatolica Obraztsov (Anatolia)
Cnephasia stephensiana stolidana (Walker) (Japan, China and Eastern Russia)
The latter also appeared in literature as Cnephasia cinereipalpana Razowski.
(Razowski, 1991b).
Biology:
stephensiana larval habitation
Eggs are deposited in July and August and hatch in 18-21 days. On hatching, the young larvae spin a silken hibernaculum and overwinter without feeding until the following April. They then feed from April to June, at first mining the leaves but later living in spun or folded leaves, the type of spinning varying with the food plant. Pupation occurs in June and July, in larval habitation or spun up in a nearby leaf or flower. Moths fly July and August.
Host plants:
The species is very polyphagous: over 120 food plants are recorded.
Records from Europe include:
Larvae of this widely distributed species are polyphagous on herbaceous plants including Carlina, Centaurea, Chenopodium, Chrysanthemum, Cirsium, Heracleum, Inula, Plantago, Primula, Sonchus, Ranunculus, Rumex, Serratula, Taraxacum, Tussilago, Vicia; occasionally on cultivated peas and beans.
Records from Japan:
Malus pumila, Rubus sp., Fragaria ananassa, Vaccinium vitis-idaea, Artemisia montana, Artemisia princeps, Erigeron annus, Cirsium spp., Solidago virga-aurea, Phaseolus sp., Trifolium repens, Medicago sativa, Mentha arvensis, Nicotiana tabacum, Populus sieboldi, Chenopodium album, Rumex obtusifolius, Heracleum moellendorfii, Diospyros kaki.
Records from Canada:
Fragaria; cultivated legumes.
Damage:
Larvae of this species are often pests of cultivated plants in gardens and glasshouses. On Plantago and Chrysanthemum leucanthemum the leaf is spun into a tube, the frass collecting at the bottom; on the other plants an edge of leaf may be folded over, or the leaf puckered on the underside, the larva living beneath in a web. Larvae also feed on flowers.
In Japan, tobacco plants are among the host plants. The larvae feed on the leaves (Alford, 1995; Bradley et al., 1973; Yasuda, 1975b).
Distribution:
Generally distributed in the Palaearctic Region. Recorded from North America (Canada) by Mutuura, 1982.
Pheromone:
Pheromone unknown.
Attractantia:
E 8-12Ac : 1
Z 8-12Ac : 1 (Witzgall et al., 1996b)
Parasitoids:
(Record from France: Chambon, 1972)
Hypomicrogaster tiro (Reinh.)