Caryocolum cassella is a moth of the family Gelechiidae. It is found in the France, Germany, Austria, Switzerland, Denmark, Scandinavia, Poland, the Czech Republic, Slovakia, Romania, Estonia, Lithuania, Ukraine, Belarus and Russia.[1] It is also found in North America, where it has been recorded from Alberta, Saskatchewan, California and Nevada.[2] A record from Hokkaido, Japan might also refer to this species.
The length of the forewings is 5.5-6.5 mm for males and 5.5–6 mm for females.[3] Adults have been recorded on wing from June to late August.
The larvae feed on Stellaria nemorum. They feed between spun shoots. Larvae can be found from May to June.