Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
We have seen samples from DE and MD with unusual leaf spot symptoms that are often limited to the veins. There is a yellowing and reddening of the tissue and veins associated with the virus infection. The symptoms can progress to a necrosis of the tissue around the veins as well. This virus disease, soybean vein necrosis virus, once it has been confirmed, would be new and a first report for our area. It has been seen in parts of the Midwest and confirmed by researchers at the University of Arkansas. They have seen pictures of the samples we have received and are sure it is SVNV. If you have seen these symptoms on soybeans we would like to know about it, and receive some leaf samples. There are differences in susceptibility to this new virus among varieties so we would need to know what variety you are growing if you see these symptoms. There may be some confusion about these symptoms because they can resemble Cercospora leaf blight caused by Cercospora kikuchii, which also causes purple seed stain.
Symptoms associated with soybean vein necrosis virus.