Adult Recognition
FWL: 8.0-12.5 mm (male); 9.5-14.0 mm (female)
Adults are brown with fasciate markings and white hindwings. Pandemis pyrusana is similar to Pandemis limitata and Pandemis canadana, and the three species are not easily separated. A combination of geographic distribution and wing color can assist in identification (see below). In the Pacific Northwest and central Rocky Mountains all three species are present and a reliable species-level identification is difficult or impossible.
Six species of Pandemis occur in the Nearctic. Four, P. canadana, P. lamprosana, P. limitata, and P. pyrusana, are native, while two, P. cerasana and P. heparana, have been introduced from the Palearctic. All species treated here have a straw (yellow) to brown forewing with brown to dark-brown markings consisting of a patch on the costa below the apex, a median band that extends from costa to dorsum, and a basal band. The two bands (or fasciae) may be lined with light or dark scales in some individuals, creating the appearance of three lines running vertically across the wing. Males have a distinctive notch at the base of the antennae and modified dark scales on the ventral surface of abdominal segments 2-3 (this character is absent in P. lamprosana and P. heparana). Males lack a forewing costal fold.
Species identification within the group is difficult. Pandemis lamprosana, P. cerasana, and P. heparana, can be identified by wing color and male genitalia. The other three species, P. canadana, P. limitata, and P. pyrusana, exhibit variable wing patterns, share identical genitalia, and cannot be reliably separated where their distributions overlap. The following table lists a combination of wing color and geographic distribution that can be used to identify many Pandemis individuals collected in the U.S.
| Pandemis species | Forewing color | Hindwing color | Sex scales on male 2nd abd. segment | Distribution |
| canadana | medium to dark brown | all gray | present | Maine, Colorado, Wyoming, Southern Canada |
| cerasana | straw to light brown | grayish brown | present | Pacific Northwest, British Columbia; Europe and Asia |
| heparana | medium brown | light to medium grayish brown | absent | Pacific Northwest, British Columbia; Europe and Asia |
| lamprosana | tan to light brown | white to light gray | absent | Northeastern U.S., southern Quebec and Ontario |
| limitata | straw to medium brown | gray and white | present | Eastern U.S. and southern Canada; generally absent in the U.S. west of the Rocky Mtns. |
| pyrusana | straw to medium brown | all white | present | Rocky Mtns. west to California, southern Alberta and British Columbia |
Larval Morphology
Late instar larvae are approximately 20 mm in length and are entirely green and unmarked with moderately large pinacula and long setae. Earlier instars may have a dark lateral mark on each side of the prothoracic shield. A well developed anal comb is present with 6-8 teeth.
MacKay (1962) examined several species of Nearctic Pandemis and could find no species-specific larval characters. Diagnostic characters for the genus include: SD2 on A1-8 on same pinaculum as SD1; L1 and L2 anterior to spiracle on A2-8; SV group on A1,2,7,8,9 usually 3:3:3:2:2; D2s on A8 as far apart as D1s; D1 on A9 on its own pinaculum; anal setae very long; anal comb with 6-8 teeth.
Biology
Pandemis pyrusana completes one or two generations per year. Adults are present in the costal areas of California from May to July and again in September to November.
Females deposit eggs in masses on the upper surfaces of leaves and on fruit. Early instar larvae of the first (summer) generation feed under a shelter constructed along the mid-rib of a leaf. Later instars feed on foliage in various locations on the host and may cause economic damage by feeding between clusters of fruit. Larvae of the second generation overwinter in shelters at the base of trees or under bark. In the spring they begin feeding on terminal leaves and pupate in April or May inside a folded leaf.
Host plants
Larvae of Pandemis pyrusana have been recorded feeding on the following host plants:
| Family | Genus/species | Common name |
| Betulaceae | Alnus Mill. | alder |
| Betulaceae | Betula occidentalis Hook. | water birch |
| Caprifoliaceae | Lonicera L. | honeysuckle |
| Cornaceae | Cornus sericea L. | redosier dogwood |
| Grossulariaceae | Ribes L. | currant |
| Rhamnaceae | Ceanothus cuneatus (Hook.) Nutt. | buckbrush |
| Rosaceae | Malus Mill. | apple |
| Rosaceae | Malus pumila Mill. | paradise apple |
| Rosaceae | Prunus avium (L.) L. | sweet cherry |
| Rosaceae | Prunus L. | |
| Rosaceae | Prunus virginiana L. | chokecherry |
| Rosaceae | Pyrus L. | pear |
| Rosaceae | Rosa L. | rose |
| Salicaceae | Populus tremuloides Michx. | quaking aspen |
| Salicaceae | Salix L. | willow |
| Salicaceae | Salix lasiolepis Benth. | arroyo willow |
| Salicaceae | Salix sessilifolia Nutt. | northwest sandbar willow |
Distribution
Pandemis pyrusana is distributed from Alberta west to British Columbia, south to Idaho, Utah, Colorado, and California.
References
Dombroskie, J. J. 2011. Aspects of archipine evolution (Lepidoptera: Tortricidae). University of Alberta, Department of Biological Sciences. Ph.D. dissertation. 488 pp.
Freeman, T. N. 1958. The Archipinae of North America (Lepidoptera: Tortricidae). The Canadian Entomologist. 90 (suppl. 7). 89 pp.
MacKay, M. R. 1962. Larvae of the North American Tortricinae (Lepidoptera: Tortricidae). The Canadian Entomologist Supplement 28: 1-182.
Newcomer, E. J., and F. W. Carlson. 1952. The leaf roller moth Pandemis pyrusana. Journal of Economic Entomology. 45: 1079-1081.
Powell, J. A. 1964. Biological and taxonomic studies on tortricine moths, with reference to the species in California. University of California Publications in Entomology. Vol. 32. 317 pp.
Photo Credits
Figs. 6-7: University of California Statewide IPM Program (UC IPM Web Site)
