The large majority of members of the family Potyviridae are aphid-transmitted. However, 17 viruses whose vectors are unknown have been classified as members of the genus Potyvirus. Loss of aphid transmissibility has been observed in some strains of several potyviruses. There are currently 11 members of the Potyviridae whose vectors are not aphids. These viruses with non-aphid vectors exhibit most of the characteristics of the family. Viruses of the Potyviridae induce cytoplasmic cylindrical inclusions in their hosts whether their vectors are aphids, non-aphids, or are unknown. The virus genome produces the inclusion protein and thus the viruses have related inclusion body gene sequences. Non-aphid-transmitted viruses of the Potyviridae also are serologically related to aphid-transmitted potyviruses.