Analysis of competence of thrips species to transmit soybean vein necrosis virus and impact of the virus on thrips vector biology and behavior

Soybean vein necrosis virus (SVNV) is an emerging viral disease affecting soybean, first discovered in Tennessee in 2008. SVNV has been identified as being a new virus in the genus Tospovirus, which are typically vectored by thrips. So far, only soybean thrips have been confirmed to transmit SVNV. However, other thrips species are found in soybean fields, including eastern flower thrips and tobacco thrips. The objectives of this study were to: 1) Determine vector competence in three thrips species including soybean, eastern flower and tobacco thrips, and 2) Determine the effect of SVNV on host plant preference and life history of the thrips vector. Vector competence assays showed that eastern flower thrips and tobacco thrips were able to acquire the virus after being exposed to SVNV-infected leaf tissues for 48 hours. Both species were also able to successfully transmit SVNV to healthy plants, but at a lower efficiency (less than 20% of the plants were infected) than soybean thrips (nearly 100% infection). SVNV infection did not influence host preference of soybean thrips that is both SVNV-infected and SVNV-uninfected soybean thrips aggregated on healthy plants compared to SVNV-infected plants. There was no correlation between SVNV levels in individual thrips any of the life history traits measured. However, SVNV-infected soybean thrips had significantly lower fecundity compared to uninfected thrips. Taken together, these results contribute to a better understanding of virus-vector interaction, which is crucial for control of SVNV, as well as control of soybean thrips.