Decodes basiplagana is a moth of the family Tortricidae. It is widespread in North America, including Illinois, Massachusetts, Minnesota, New Jersey, Oklahoma, Ontario, Tennessee and Wisconsin The length of the forewings is 8.1-9 mm. Adults have gray forewings with a strongly arched costa. The forewing pattern varies greatly. While some specimens have well defined dark gray and black fasciate markings, others are unmarked. The larvae feed on Quercus lobata.