Decodes fragariana

Status

NATIVE

DOMESTIC SURVEY

Taxonomy

Decodes fragariana (Busck) (Tortricidae: Tortricinae: Cnephasiini)

Synonyms: elapsa (Peronea)

Adult Recognition

FWL: 6.0–8.5 mm

Forewings are gray with a strongly arched costa. Forewing pattern varies, with some specimens marked with well-defined dark-gray fasciae and others unmarked. Males lack a forewing costal fold.

Male genitalia are characterized by a long, narrow, minutely spined uncus; setose socii; and elongate valvae. Female genitalia are characterized by unusual, modified papillae anales; and corpus bursae without a signum.

Larval Morphology

Larvae have not been described.

Similar Species

Decodes basiplagana is similar, but males have an aedeagus that is curved less than 90 degrees and females have a signum in the corpus bursae. Decodes montanus is similar to both species, but the male aedeagus is more strongly curved than in D. fragariana and females of D. montanus have a band of dark scales on the seventh sternite that is lacking in the other two species. Wing pattern is not diagnostic and cannot be used to reliably separate the Decodes species included on this site.

Cnephasia stephensiana and other species of Cnephasia can appear superficially similar. The valvae of D. fragariana are much more slender than in C. stephensiana and do not have such a well-sclerotized sacculus. Females of D. fragariana have a significantly smaller signum than in C. stephensiana.

Distribution

Decodes fragariana ranges from British Columbia south to southern California and east to Utah, Colorado, and New Mexico.

Biology

The following account is summarized from Powell (1964b)Powell (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..

Decodes fragariana completes one generation per year in California. Adults are present in late August through October. Females deposit eggs on rough twigs or bark and cover them with debris. The eggs enter diapause and overwinter until the following spring. Larvae hatch in the spring, construct a silken feeding tube on the bottom of a leaf or between two leaves, and feed on new growth until mature. Mature larvae drop to the ground and pupate in silk cocoons covered in soil or other particles. Adults eclose in the fall.

This species was originally described as feeding on strawberry (Fragaria spp.); however, D. fragariana has subsequently been recorded feeding only on oak (Quercus spp.). Powell and Opler (2009)Powell and Opler (2009):
Powell, J. A., Opler, P. A. 2009. Moths of western North America. University of California Press, Berkeley. 369 pp. suggest that the individuals found in association with strawberry were simply pupating after having completed larval development on nearby oak trees. Thus, the specific epithet may be a misnomer.

Plant Associations

View full screen host table here

Links

Additional photos and a distribution map of this species in North America are available at Moth Photographers Group.