PSV is transmitted from plant to plant by several species of aphids ("Aphis craccivora", "A. spiraecola" and "Myzus persicae") in a stylet-borne manner. It can also be transmitted by mechanical inoculation. It has been shown to be transmitted by seeds in peanuts at a very low level  but this is not considered to be very important to the spread of this virus. The virus can be introduced into a susceptible field crop by aphids from a nearby reservoir (infected perennial hosts like clover, alfalfa or perennial peanuts) and then is spread further into the field by aphids. It can be spread in perennial crops by harvesting (mechanical transmission) and possibly by root grafts. Correct diagnosis of any plant disease requires some expertise. Plants suspected of a viral infection should be sent to a plant diagnostic laboratory where the presence or absence of the virus can be confirmed by serological ( ELISA ), genetic (PCR), or host range tests. Antiserum and sequence data are available for this virus.