Effect of Host Plant, Aphid Species, and Virus Infection Status on Transmission of Sweetpotato feathery mottle virus.

Sweetpotato feathery mottle virus (SPFMV) is a nonpersistently transmitted virus known to infect sweetpotato (Ipomoea batatas) and wild morning glory plants. SPFMV is vectored by various aphid species, among them the green peach aphid, Myzus persicae, and the cotton aphid, Aphis gossypii. Our objective was to determine whether differences in acquisition hosts (sweetpotato and morning glory), aphid species (M. persicae and A. gossypii), and infection status (single versus mixed infection) influenced transmission of SPFMV. SPFMV transmission from I. hederacea with a natural mixed infection by A. gossypii (39%) was significantly greater than in other host-virus combinations. Successful transmissions by A. gossypii were significantly greater compared with M. persicae in all host-virus combinations. Virus titers in source leaves were significantly greater in single- and mixed-infected I. hederacea and single-infected I. cordatotriloba compared with other host-virus combinations. There was a significant positive correlation between virus titer and transmission by both aphid species. These results suggest that, under controlled conditions, SPFMV is more readily transmitted from infected morning glory plants than from sweetpotato. Additionally, mixed-infected plants are better virus sources for transmission than single-infected, and A. gossypii is a more efficient vector than M. persicae under laboratory conditions.