A new virus to notice in soybeans

decrease font size  Resize text   increase font size       Printer-friendly version of this article Printer-friendly version of this article

Change is always the name of the game when it comes to diseases that affect our field crops. Efforts to observe, detect, diagnose, and manage pests need to be as flexible as the pathogens are -- which is a long way of saying, "There is a new disease you may have noticed in your soybean fields." If you've been monitoring soybean fields for late-season pests, you may have noticed very odd symptoms on some leaves.

Have you seen large, brown, blotchy lesions that run in the direction of the leaf veins and look a bit like the leaf was scratched with something abrasive and then tried to scab over the scratch? That symptom is characteristic of a new disease of soybean called soybean vein necrosis virus, or SVNV.

We have seen this symptomology in soybean leaf samples at the plant clinic for the past several years, and now we know its cause. A 2010 survey of soybean fields conducted by USDA-ARS virologist Les Domier of the University of Illinois Department of Crop Sciences showed that the disease is found throughout Illinois and is the second-most prevalent virus found in Illinois soybean fields, right after bean pod mottle virus. That is an amazing feat for a pathogen that not only causes a new disease but is itself a newly described virus.

click image to zoomPhoto courtesy of the University of Illinois Plant ClinicLeaf symptoms of several virus diseases in Illinois. The leaflets at upper left and lower right show typical symptoms of soybean vein necrosis virus (SVNV)—brownish (necrotic) lesions running along the veins. The virus is transmitted to soybean by the insect thrips. Domier notes that SVNV is in the tospo family of viruses, unusual in that they replicate not only in an infected plant but also in their thrips vectors. So thrips that are carrying SVNV can transmit it for a long time.

Symptoms of SVNV in Illinois typically start showing up in August, which is certainly the case this year. Infected leaves may just have a single necrotic scabby lesion or may have many large lesions. Symptoms may be restricted to a scabby necrosis along the veins or may spread widely from the veins. Initial studies and observations in Arkansas note that symptoms do vary with the cultivar, as we seem to be seeing here. Let's hope that this variation in symptomology points to a source of genetic resistance, as has been the case for other pathogens. Changing disease and pest populations keep us all on our toes and remind us to remain flexible and vigilant in our scouting expeditions.


Buyers Guide

Doyle Equipment Manufacturing Co.
Doyle Equipment Manufacturing prides themselves as being “The King of the Rotary’s” with their Direct Drive Rotary Blend Systems. With numerous setup possibilities and sizes, ranging from a  more...
A.J. Sackett Sons & Company
Sackett Blend Towers feature the H.I.M, High Intensity Mixer, the next generation of blending and coating technology which supports Precision Fertilizer Blending®. Its unique design allows  more...
R&R Manufacturing Inc.
The R&R Minuteman Blend System is the original proven performer. Fast, precise blending with a compact foot print. Significantly lower horsepower requirement. Low inload height with large  more...
Junge Control Inc.
Junge Control Inc. creates state-of-the-art product blending and measuring solutions that allow you to totally maximize operating efficiency with amazing accuracy and repeatability, superior  more...
Yargus Manufacturing
The flagship blending system for the Layco product line is the fully automated Layco DW System™. The advanced technology of the Layco DW (Declining Weight) system results in a blending  more...
Yargus Manufacturing
The LAYCOTE™ Automated Coating System provides a new level of coating accuracy for a stand-alone coating system or for coating (impregnating) in an automated blending system. The unique  more...
John Deere
The DN345 Drawn Dry Spreader can carry more than 12 tons of fertilizer and 17.5 tons of lime. Designed to operate at field speeds up to 20 MPH with full loads and the G4 spreader uniformly  more...
Force Unlimited
The Pro-Force is a multi-purpose spreader with a wider apron and steeper sides. Our Pro-Force has the most aggressive 30” spinner on the market, and is capable of spreading higher rates of  more...
BBI Spreaders
MagnaSpread 2 & MagnaSpread 3 — With BBI’s patented multi-bin technology, these spreaders operate multiple hoppers guided by independent, variable-rate technology. These models are built on  more...


Comments (0) Leave a comment 

Name
e-Mail (required)
Location

Comment:

characters left


Pacesetter Grain Hopper

The Pacesetter Gain Hopper features original and innovative ideas like the patented RollerTrap™, the industry’s easiest to open and maintain trap ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form