Infection of Sweet Potato by Cucumber Mosaic Virus Depends on the Presence of Sweet Potato Feathery Mottle Virus. J. Cohen, Department of Virology, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. G. Loebenstein, and Sara Spiegel. Department of Virology, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. Plant Dis. 72:583-585. Accepted for publication 26 January 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0583.

Cucumber mosaic virus (CMV) severely infects sweet potato fields in Israel causing stunting, chlorosis, and yellowing of plants. Identification of CMV was based on host range, serology, and electron microscopy. All CMV-infected field plants also carried sweet potato feathery mottle virus (SPFMV). Transmission of CMV by mechanical, grafting, and aphid inoculations to healthy sweet potato plants failed, but it was achieved easily if the acceptor plants carried SPFMV. Apparently, for replication of CMV in sweet potato, a factor is required that is provided by the presence of SPFMV. This seems to be the first report that CMV has a helper virus requirement.