Native
Choristoneura conflictana (Walker) (Tortricidae: Tortricinae: Archipini)
Common name: large aspen tortrix
FWLFWL:
forewing length; the distance from the base of the forewing to the apex, including fringe
: 12-17 mm
Head and abdomen gray to light brown, forewing similarly colored but fasciaefascia:
a dark transverse band on the forewing
darker, often brown. In some specimens, the banding is nearly obsolete; hindwing brown. Males lack a forewing costal foldforewing costal fold:
a flap or fold at the base of the forewing that contains specialized sex scales
.
Male genitalia are characterized by short, quadrate valvaevalva:
an appendage flanking the intromittent organ that is used to clasp the female during copulation
with a well-sclerotized sacculussacculus:
the ventral margin of the male valva 
with an abruptly angular subapical projection on the ventralventral:
lower, to the bottom, on the under side
margin and a finger-like uncusuncus:
a sclerotized process which is fused to the posterodorsal margin of tergum IX
(Dang 1992Dang 1992:
Dang, P. T. 1992. Morphological study of male genitalia with phylogenetic inference of Choristoneura Lederer (Lepidoptera: Tortricidae). Canadian Entomologist. 124: 7-48.). Female genitalia are characterized by a long, distally sclerotizedsclerotized:
hardened; usually in reference to larval structures or adult genitalia 
ductus bursaeductus bursae:
a membranous tube connecting the ostium bursae to the corpus bursae
and a hook-like signumsignum:
a sclerotized projection or patch on the interior of the corpus bursae
with a large capitulumcapitulum:
in reference to the female signum; a knoblike projection 
.
The following account is summarized from Prentice (1955)Prentice (1955):
Prentice, R. M. 1955. The life history and some aspects of the ecology of the large aspen tortrix, Choristoneura conflictana (Wlkr.) (n. comb.) (Lepidoptera: Tortricidae). Canadian Entomologist. 87(11): 461-473..
First instar larvae are 1.8-2.0 mm in length, with head, prothoracic shieldprothoracic shield:
a sclerotized plate on the dorsal surface of the prothorax 
, and anal shieldanal shield:
a sclerotized plate on the dorsal surface of the last abdominal segment (in larvae) 
light brown. The body is pale yellow-green. During the third instar, the body color changes to grayish-green and the head, prothoracic shieldprothoracic shield:
a sclerotized plate on the dorsal surface of the prothorax , and anal shieldanal shield:
a sclerotized plate on the dorsal surface of the last abdominal segment (in larvae) darken. Mature (fifth instar larvae) range in length from 15-21 mm and are usually dark green in coloration, sometimes entirely black.
A more detailed account of larval chaetotaxychaetotaxy:
the arrangement of setae (in reference to Lepidoptera larvae), often depicted on a "setal map"
is available in Prentice (1955)Prentice (1955):
Prentice, R. M. 1955. The life history and some aspects of the ecology of the large aspen tortrix, Choristoneura conflictana (Wlkr.) (n. comb.) (Lepidoptera: Tortricidae). Canadian Entomologist. 87(11): 461-473..
Choristoneura conflictana is unlikely to be confused with other Nearctic species of Choristoneura due to their distinctive gray wash to the forewing. Other species are almost always shades of brown or red.
The following account is summarized from Prentice (1955)Prentice (1955):
Prentice, R. M. 1955. The life history and some aspects of the ecology of the large aspen tortrix, Choristoneura conflictana (Wlkr.) (n. comb.) (Lepidoptera: Tortricidae). Canadian Entomologist. 87(11): 461-473..
In northern Manitoba and Saskatchewan, eggs are laid in flat clusters of approximately 60 to 450 eggs in mid-June to early July. Larvae hatch in early to mid-July, disperse, and feed gregariously on the epidermal layer of leaves of the host plant until mid- to late August. Larvae molt once and overwinter as second instars in spun hibernacula under bark of the host tree. In the spring, second instar larvae emerge and re-ascend the tree to begin feeding again, usually in early to mid-May, just before the aspen buds break. These larvae will then mine the aspen buds. Larvae molt to the third instar from within the bud. Once the non-damaged buds expand, larvae move out of the damaged buds and begin feeding externally by rolling leaves and feeding from within. This behavior is done throughout the third, fourth, and fifth (final) instars. Pupation occurs within a rolled leaf. Pupation occurs from early to mid-June, with adults eclosing in mid-June to early July after a pupal period of about 7-14 days, depending on weather conditions. Females deposit an average of 200 to 400 eggs in one or more clusters.
The preferred host for C. conflictana is trembling aspen (Populus tremuloides). In outbreak years, larvae have been recorded on several other broad-leaved trees because of lack of available trembling aspen. Severe to near complete defoliation of large stands of trembling aspen can occur, occasionally for several years in row.
| Host plant | Host plant family | Reference(s) |
| Acer negundo | Aceraceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Acer sp. | Aceraceae | Powell 1964bPowell 1964b: Powell, J. A. 1964b. Biological and taxonomic studies on tortricine moths, with reference to the species in California. University of California Publications in Entomology. Vol. 32. 317 pp. |
| Alnus incana | Betulaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Betula alleghaniensis | Betulaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Betula papyrifera | Betulaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Betula populifolia | Betulaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Betula sp. | Betulaceae | Powell 1964bPowell 1964b: Powell, J. A. 1964b. Biological and taxonomic studies on tortricine moths, with reference to the species in California. University of California Publications in Entomology. Vol. 32. 317 pp. |
| Corylus sp. | Betulaceae | Prentice 1966 |
| Cornus alternifolia | Cornaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Vaccinium sp. | Ericaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Picea glauca | Pinaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Pinus banksiana | Pinaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Pinus strobus | Pinaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Amelanchier sp. | Rosaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Malus sp. | Rosaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Prunus pensylvanica | Rosaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Prunus virginiana | Rosaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Prunus sp. | Rosaceae | Powell 1964bPowell 1964b: Powell, J. A. 1964b. Biological and taxonomic studies on tortricine moths, with reference to the species in California. University of California Publications in Entomology. Vol. 32. 317 pp.; LACM IndexLACM Index: LACM Index. Records from the card file at the Los Angeles County Museum of Natural History, Los Angeles, California; transcribed by Gaeden Robinson (BMNH). |
| Rosa sp. | Rosaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Sorbus sp. | Rosaceae | Prentice 1966Prentice 1966: Prentice, R. M. 1966. Vol. 4. Microlepidoptera. In : Forest Lepidoptera of Canada recorded by the Forest Insect Survey. Dept. For. Canada Publ. 1142: 543-840. |
| Populus alba | Salicaceae |
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Choristoneura conflictana is primarily boreal in its distribution, being found almost anywhere trembling aspen naturally grows. In Canada, this corresponds to most areas except northern Quebec and the Northwest Territory. In the United States, C. conflictana reaches the southern limits of its range in New York, Indiana, California, and south through the Rocky Mountains to at least New Mexico.
