Soybean vein necrosis virus, a newdisease in Indiana soybeans, was confirmed earlier this month, a PurdueExtension plant pathologist says. A soybean sample exhibiting symptoms of the virus, alsoknown as SVNV, was sent to Purdue’s Plant and Pest Diagnostic Laboratory. Thelaboratory sent the plant sample to Agdia Inc. for further testing. Moleculartest results confirmed the presence of a tospovirus, or a disease causing celldeath, in the sample. “SVNV is one of our newer viruses that we’veconfirmed in soybeans,” said Kiersten Wise. “This is the first yearthat we’ve confirmed it in Indiana, although we’ve seen suspect symptoms in thepast.”
While the disease doesn’t appear to affect yield, it doescause foliar symptoms similar to herbicide injury, including yellowing in ornear plant veins and light green patches or mottled green and brown speckledareas associated with veins. Leaves will show a blotchier, scorched appearancein shades of orange and yellow. As the season progresses, Wise said the viruscould cause tissue death, which can leave a scorched appearance on severelyaffected plants.
Since the discovery of SVNV by a University of Arkansas professorin 2008, the virus had been reported in 12 states: Arkansas, Delaware,Kentucky, Kansas, Illinois, Maryland, Missouri, Mississippi, New York,Pennsylvania, Tennessee and Virginia.
The virus is spread by thrips, insects that infest avariety of plant species.”When those insects are feeding on the soybeans, theymay be transmitting this virus as well,” Wise said. “We suspectthat’s why we’re seeing more symptoms this year, because we’ve had more thripsdamage in soybeans.” Calling the virus an “oddity,” she said farmersare seeing more of it this year than ever before. “It’s all across Indiana from the Kentucky border allthe way up to the Michigan border. And growers are concerned about what theseblotches are on their soybeans,” Wise said.
But even with the high incidence of SVNV, she doesn’trecommend any treatment. “We are still learning more about this virus, andwe’re going to continue to monitor it in the future,” Wise said. “Butat this point in time we wouldn’t recommend any changes in productionpractices.” Wise encouraged growers and crop consultants to inspectany still-green soybean plants for symptoms of soybean vein necrosis and emailimages of possible cases to firstname.lastname@example.org