PRSV is sap transmissible and reported to be vectored by many species of aphids, including Myzus persicae, Aphis gossypii, A. craccivora, and A. maidis in a non-persistent manner (Purcifull et al. 1984). This mode of transmission is
characterised by a short acquisition period followed by rapid loss of infectivity (Purcifull et al. 1984). An entire papaya orchard can become completely infected with PRSV in three to four months (Gonsalves 1994, 1998). Losses up
to 70% have been reported in some regions (Barbosa and Paguio 1982). Although transmission is widely shown to be by aphid vectors, one study in the Philippines reported seed transmission of PRSV (Bayot et al. 1990). Two of 1355 seedlings (0.15%) from fruit of an infected tree were reported to develop symptoms of PRSV six weeks after emergence.