Incidence of soybean vein necrosis virus in Alabama soybean fields

Abstract

Soybean vein necrosis virus (SVNV) was first reported in the United States during 2008 and has since rapidly spread to all major soybean-producing regions of North America. In 2013, a 4-year study was initiated to determine the distribution and incidence of the virus in Alabama soybean fields and potential weed hosts in the state. The weed host survey focused on populations of morning glory growing adjacent to maturing soybeans fields, along with additional commonly occurring weed species found in Alabama. SVNV was detected throughout Alabama (27 of 28 counties tested) and was most common in the northern region of the state. The average incidence of SVNV in fields in northern Alabama increased from31.8%in 2013 to 82.6%in 2016. Average incidence of the virus in central Alabama soybean fields ranged from 5.1 to 14.8%, and southern Alabama fields ranged from 0 to 8.8% over the 3-year period. Only one population of morning glory tested positive for SVNV during the 3-year survey of this potential weed host. None of the 15 additional weed species screened tested positive for SVNV. This study has demonstrated that SVNV is found in Alabama soybean fields throughout the state and that soybeans grown in northern Alabama are at greater risk for infection.