E. N. Wosula, Department of Plant Pathology and Crop Physiology,
J. A. Davis, Department of Entomology, and
C. A. Clark, Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge 70803;
T. P. Smith, Sweet Potato Research Station, Louisiana State University Agricultural Center, Chase 71324;
R. A. Arancibia, Pontotoc Ridge-Flatwoods Branch Experiment Station, North Mississippi Research and Extension Center, Mississippi State University, Pontotoc 38863; and
F. R. Musser and
J. T. Reed, Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State 39762
Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), and Sweet potato virus 2 (SPV2) are sweetpotato (Ipomoea batatas) potyviruses nonpersistently transmitted by aphids. Our objective was to determine how aphid abundance, aphid species diversity, and virus titers relate to the spread of SPFMV, SPVG, and SPV2 in Louisiana and Mississippi sweetpotato fields. The most abundant aphid species were Aphis gossypii, Myzus persicae, Rhopalosiphum padi, and Therioaphis trifolii. Aphids were captured during the entire crop cycle but virus infection of sentinel plants occurred mainly during the months of June to August. SPFMV was more commonly detected than SPVG or SPV2 in sentinel plants. Virus titers for SPFMV were higher in samples beginning in late June. Because significant aphid populations were present during April to June when virus titers were low in sweetpotato and there was very little virus infection of sentinel plants, low virus titers may have limited aphid acquisition and transmission opportunities. This is the first study to comprehensively examine aphid transmission of potyviruses in sweetpotato crops in the United States and includes the first report of R. maidis and R. padi as vectors of SPFMV, though they were less efficient than A. gossypii or M. persicae.