WEST LAFAYETTE, Ind. — Soybean vein necrosis virus, a new
disease in Indiana soybeans, was confirmed recently, a Purdue Extension plant
A soybean sample exhibiting symptoms of the virus, also
known as SVNV, was sent to Purdue’s Plant and Pest Diagnostic Laboratory.
The laboratory sent the plant sample to Agdia Inc. for
further testing. Molecular test results confirmed the presence of a tospovirus,
or a disease causing cell death, in the sample.
“SVNV is one of our newer viruses that we’ve confirmed in
soybeans,” said Kiersten Wise. “This is the first year that we’ve confirmed it
in Indiana, although we’ve seen suspect symptoms in the past.”
While the disease doesn’t appear to affect yield, it does
cause foliar symptoms similar to herbicide injury, including yellowing in or
near plant veins and light green patches or mottled green and brown speckled
areas associated with veins.
Leaves will show a blotchier, scorched appearance in shades
of orange and yellow.
As the season progresses, Wise said the virus could cause
tissue death, which can leave a scorched appearance on severely affected
Since the discovery of SVNV by a University of Arkansas
professor in 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 a variety
of plant species.
“When those insects are feeding on the soybeans, they may be
transmitting this virus, as well,” Wise said.
We suspect that’s why we’re seeing more symptoms this year,
because we’ve had more thrips damage in soybeans.”
Calling the virus an “oddity,” she said farmers are seeing
more of it this year than ever before.
“It’s all across Indiana from the Kentucky border all the
way up to the Michigan border. And growers are concerned about what these
blotches are on their soybeans,” Wise said.
But even with the high incidence of SVNV, she doesn’t
recommend any treatment.
“We are still learning more about this virus, and we’re
going to continue to monitor it in the future,” Wise said.
“But at this point in time we wouldn’t recommend any changes
in production practices.”
Wise encouraged growers and crop consultants to inspect
soybean plants for symptoms of soybean vein necrosis and email images of
possible cases to firstname.lastname@example.org.