June 5, 2012

Soybean Vein Necrosis Virus​

Last August I walked through a Channel® soybean demonstration plot at the Galena Research Farm and asked Jennifer Yates, a soybean breeder at the Galena location, if she could identify for me the disease with symptoms that resembled scald or even Cercospera leaf blight. She identified the disease as Soybean Vein Necrosis Virus (SVNV), an unfamiliar disease at that time. However, it quickly became common in soybeans throughout much of the territory I am associated with — Virginia through New York.

SVNV was first identified in 2008 by Loannis Tzanetakis, Assistant Professor of Plant Pathology at the University of Arkansas, Division of Agriculture. The plant samples she observed were collected in Tennessee by John Rupe, a University of Arkansas plant pathologist. In addition to Tennessee, SVNV was discovered in Illinois and Kentucky in 2009 and caused widespread significant damage in soybean fields in Arkansas in 2010. In 2011, SVNV infection was confirmed in Virginia, Maryland, Delaware, Pennsylvania and New York.

Soybeans with Vein Necrosis Virus

This virus belongs to a group of thrips-transmitted viruses known as tospo viruses. Other commonly found tospo viruses are Tomato Spot Wilt Virus and Impatiens Necrotic Spot Virus. Thrips acquire the viruses by feeding on infected plants and subsequently transmit them to non-infected plants as they feed. Therefore, by controlling the vector of transmission – thrips – the viruses may be managed. Another SVNV management avenue includes the identification of varietal resistance as infection levels appear to vary by variety. This virus is not known to be seed transmitted.

At this time, the economic impact on soybean production from SVNV (as the only plant infection) has not been determined. There is greater concern for a potential yield loss when plants are infected with multiple viruses.

While evaluating soybean fields this summer, please observe the crop for SVNV symptoms and note any correlation to thrips pressure. In addition, scout for other common pests. If SVNV is found, please communicate your finding to your local Channel CSTA and/or District Sales Manager.​​

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Sources: http://www.planthealth.info/viruses_basics.htm http://agdev.anr.udel.eduweeklycropupdate/?p=3727