Staying on top of all the latest ag technology, field data and research can be overwhelming. That’s why the Soybean Research & Information Initiative, formerly the Plant Health Initiative, continually provides you with access to expert information and news about soybean pests, diseases, and agronomics. The aim of this check off-funded website is to communicate the on-going progress and current understanding coming from your active and wide-ranging U.S. soybean research programs. Please visit often!

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Major Findings on Soybean Vein Necrosis Virus: Seed Transmission and Impact on Seed Quality
Mon, Feb 1, 2016
Major Findings on Soybean Vein Necrosis Virus:  Seed Transmission and Impact on Seed Quality
by Damon Smith, Soybean Plant Pathologist, University of Wisconsin

Soybean vein necrosis (SVN) has become the most noticeable virus disease of soybean in the Midwest, and has caused significant damage in soybean fields in the south. The soybean vein necrosis virus (SVNV) has likely been in soybeans for some time, but was probably overlooked or misdiagnosed before recent detections. Symptoms of SVNV infection are a distinct yellowing and browning of soybean leaves that can lead to leaf death.

With funding provided by the Wisconsin Soybean Marketing Board, Iowa Soybean Association, Indiana Soybean Alliance, North Central Soybean Research Program, and the USDA, Extension plant pathologists and soybean entomologists in six states have collaborated over the past three years to determine the importance of this virus for Midwestern growers. We've  made some significant progress in our understanding of this soybean virus disease:
  • In a landmark study, we have shown that SVNV can be transmitted in seed and systemically transmitted to the emerging seedlings at a rate of approximately 6%. It is the first virus of its type to be implicated in seed transmission.
  • Soybean thrips (Neohydatothrips variabilis) are the only known insect vector at this time, arriving in multiple flights during the growing season. It is not likely that controlling thrips populations will be an effective management strategy for SVN, although this is still under study.
  • SVNV infection of soybean plants can result in a higher protein content and lower oil content of seed. The virus does not appear to have a strong impact on yield. Plants infected with SVNV may have slightly larger and heavier seed.
These findings have particular relevance for soybean seed producers. We encourage soybean seed producers to be diligent about scouting their crop and testing plants for SVNV.  Farmers growing for the high-oleic market should be aware that SVNV can reduce oil content in soybeans and source their soybean seeds from suppliers who use SVNV screening measures. We are continuing studies on the agronomic impact of SVNV in seed and in soybean plants.

View the SVN scouting video
Read Soybean Vein Necrosis Virus -  a full-color bulletin  with close-up photos of SVN symptoms and seven look-alike diseases.
Read Seed Transmission of Soybean vein necrosis virus: The First Tospovirus Implicated in Seed Transmission, Web PLOS | ONE, 19 January 2016