SWEET POTATO FEATHERY MOTTLE VIRUS (SPFMV) belongs to potyviruses, the largest group of plant positive sense single stranded RNA viruses. It has long been recognized to infect sweet potatoes worldwide. The virus is transmitted mechanically and by several genera of aphids including the cotton aphid (Aphis gossypii) and the green peach aphid (Myzus persicae) in a nonpersistent manner. SPFMV is a major component of sweet potato virus disease that is drastically affecting the yield of sweet potatoes worldwide.

Before the advances of data obtained by sequencing of potyviruses, species and strains of viruses were distinguished on the bases of host range, symptoms on indicator plants and serological relationships. Currently, availability of coat protein and the full genome sequences established the criteria that can be used in particular to distinguish sequences representing closely-related virus species from those strains of the same species. Additionally, comparisons showed that nucleotide sequences of the 3′ untranslated region of the potyviral genome can serve as an aid to identify and classify potyviruses. Increased knowledge of conserved viral sequences allowed the design of oligonucleotide primers for their use in reverse transcriptional polymerase chain reaction (RT-PCR) amplification and rapid identification of uncharacterized potyviruses.