About Tamalia coweni (Cockerell, 1905)
Tamalia coweni, commonly called the manzanita leaf gall aphid and the fold-gall aphid, is an aphid species belonging to the family Aphididae. This species induces galls on most species of glabrous manzanita trees. It produces two distinct types of galls: midrib or margin leaf galls, and a less common type of inflorescence gall. Tamalia coweni is common along the Pacific coast of North America, and ranges eastward to Nevada and Colorado. Tamalia inquilina, an inquiline that lives alongside this species, occurs in the Californias. The recently described species Tamalia glaucensis specifically induces leaf galls on big-berry manzanita.
