Adult Recognition
FWL: 8.0-9.0 mm
Forewings are gray with a strongly arched costa. Forewing pattern varies greatly, with some individuals expressing well-defined dark-gray and black fasciate markings, and others being unmarked. Males lack a forewing costal fold.
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 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 listed here.
Biology
The life history of D. basiplagana is unknown, although it is assumed to be similar to that of D. fragariana.
Host plants
Larvae have been recorded feeding on oak.
| Family | Genus/species | Common name |
| Fagaceae | Quercus L. | oak |
| Fagaceae | Quercus lobata Nee | valley oak |
Distribution
Decodes basiplagana is recorded from the eastern U.S. and ranges west into central Texas, Colorado, Utah, Arizona, and central California.
References
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.
Powell, J. A. and P. A. Opler. 2009. Moths of western North America. University of California Press, Berkeley. 369 pp.
