Soybean Vein Necrosis Virus Identified in Iowa

July 18, 2013

By Daren Mueller, Department of Plant Pathology and Microbiology

Soybean vein necrosis virus (SVNV) was first confirmed in Iowa last season. Last year we did not see SVNV until August. This past week we identified SVNV in several locations in Iowa. It is not known yet if earlier symptoms may increase chances of yield loss. We will continue to monitor and provide updates.

The virus belongs to the tospovirus group, which is vectored by thrips and possibly other insects. Symptoms often begin as chlorotic (light green to yellow) patches near the main veins, which may enlarge eventually becoming necrotic (brown) areas (Figure 1). The veins may appear clear, yellow or dark brown. The browning of the veins may be especially noticeable on the lower leaf surface (Figure 2), but this may not always occur.

Currently, there are no management recommendations for this disease. Other pathosystems that include thrips and tospoviruses, including tomato spotted wilt virus, focus on resistance and management of the vector. Because of the newness of this disease, there are no known sources of resistance. Insecticide application only should be considered in fields with a known risk of yield loss.

Figure 1. Foliar symptoms of SVNV on soybean

 

Figure 2. Browning of the veins on the lower leaf surface

 

Daren Mueller is an assistant professor in the Department of Plant Pathology and Microbiology. He can be reached at 515-460-8000 or e-mail

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 18, 2013. The information contained within may not be the most current and accurate depending on when it is accessed.

ICM News
Crop: 
Author: 

Daren Mueller Assistant Professor

Dr. Daren Mueller is an assistant professor and extension plant pathologist at Iowa State University. He is also the coordinator of the Iowa State University Integrated Pest Management (IPM) program. Dr. Mueller eraned his bachelor's degree from the Unive...