Soybean Diseases Starting to Wake Up

August 21, 2013
ICM News

By Daren Mueller, Department of Plant Pathology and Microbiology

After taking much of the growing season off, soybean diseases are finally starting to wake up and make a bit of noise.

Soybean rust

Yes, you read correctly, a soybean rust update. It has been a few years. Dr. Carl Bradley has a nice article on the status and risk of soybean rust in Illinois. The article includes the most common look-alike diseases.

In general, soybean rust is building up in the southern states a bit sooner than previous years, and there are quite a bit of late-planted soybeans that could be affected in these southern states. As of now, most of the soybean rust finds are too far east for them to provide spores that could infect Iowa fields. But it is certainly worth keeping an eye on over the next several weeks because we do have late-planted soybeans that could be affected. For the latest distribution of soybean rust, visit the IPM PIPE webpage. If you suspect you have soybean rust, please send soybean leaves to the ISU Plant and Insect Diagnostic Clinic.

Sudden death syndrome

Sudden death syndrome (SDS) has been reported in several counties in southeastern Iowa. As a reminder, SDS typically shows up in patches, often at the edges of fields or in low-lying areas. See images for early and more advanced symptoms. Remember to split the stem to differentiate from brown stem rot, which will have the characteristically brown discolored pith.

With support from USDA and checkoff dollars, Dr. Leonor Leandro is collecting isolates of the fungus that causes SDS from across Iowa. If you have SDS in your field, we are very interested in collecting a few infected plants for research purposes. If you can mail a few infected plants, including the roots, to the address below or send an email to Dr. Leandro or myself to arrange for us to get the plants, it would be very much appreciated.

Dr. Leonor Leandro
351 Bessey Hall
Ames, IA 50011


Soybean vein necrosis virus

We continue to see soybean vein necrosis virus (SVNV) in Iowa, especially the southern half of the state. However, most fields that have the virus have fairly low levels. See the previous ICM article for information on how to identify this disease.


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 August 21, 2013. The information contained within may not be the most current and accurate depending on when it is accessed.


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...