Phorodon cannabis Passerini (Hemiptera: Aphididae: Macrosiphini) is reported for the first time as a pest of Cannabis L. crops in North America. The insect has been confirmed from fields of industrial hemp in Colorado and Virginia and has been found present within greenhouses in at least several American states and one Canadian province. The generic position of the aphid species is discussed and other known members of the genus are ruled out. Phorodon cannabis is placed in genus Phorodon Passerini and subgenus (Diphorodon Börner). Phorodon persifoliae Shinji is transferred to Hyalopterus Koch as a nomen dubium