Recognition
Diagnostic features
Adults
FWL: 8.1-9.0mm
Adults have gray forewings with a strongly arched costa. Forewing pattern varies greatly; some specimens have well defined dark gray and black fasciate markings while others are unmarked. Males lack a costal fold.
Males have an aedeagus that is curved less than 90 degrees. The female corpus bursae contains a signum. Both of these characters serve to separate this species from D. fragariana.
Related or similar species
Decodes fragariana is similar, but males have an aedeagus that is curved more than 90 degrees and females lack a signum in the corpus burase. Decodes montanus (not treated here) is similar to both species, but the male aedeagus is more strongly curved than in fragariana and females of 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 listed here.
Biology
Life history
The life history of basiplagana is unknown; it is probably similar to that of fragariana.
Host plants
Larvae have been recorded from valley oak (Quercus lobata).
Area of origin
North America
Distribution
Widespread throughout North America
Taxonomy
Current valid name
Decodes basiplagana (Walsingham)
Common names
- [Tortrix moth]
Synonyms
- Sciaphila basiplagana
Placement
Tortricinae: Cnephasiini
Selected References
Brown, J. W., G. Robinson and J. A. Powell. 2008. Food plant database of the leafrollers of the world (Lepidoptera: Tortricidae) (Version 1.0.0). http://www.tortricidae.com/foodplants.asp.
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.
