Soybean Cyst Nematode Females now Apparent on Soybean Roots

July 15, 2008
ICM News

by Greg Tylka, Department of Plant Pathology

Many Iowa soybean fields may be infested with the soybean cyst nematode (SCN) but the infestations may not be known because SCN does not always cause obvious, above-ground symptoms. In fact, yield loss of up to 40 percent has been documented without above-ground symptoms occurring.

An easy, free and reliable way to check fields for the presence of SCN is to dig roots of susceptible soybean varieties. Carefully crumble away much of the soil from the roots, and look for the adult SCN females on the roots. The females appear as small, round, white objects on the roots and are about the size of a period at the end of a sentence.

We recently observed adult SCN females on soybean roots in research plots in central Iowa. The soybeans were planted in late May. SCN females will be apparent on young roots of susceptible soybean plants in Iowa through July and August, and probably early September this year.  Roots should be checked for SCN females no earlier than four or five weeks after planting.

Additional information about the biology, sampling, and management of the soybean cyst nematode Web site.

Adult SCN females (yellow arrows) on soybean root.  The two larger round objects (blue arrows) are nitrogen-fixing nodules.


Greg Tylka is a professor of plant pathology with extension and research responsibilities in management of plant-parasitic nematodes.

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 15, 2008. The information contained within may not be the most current and accurate depending on when it is accessed.


Greg Tylka Morrill Professor

Dr. Greg Tylka is a Morrill Professor in the Department of Plant Pathology and Microbiology at Iowa State University with extension and research responsibilities for management of plant-parasitic nematodes. The focus of Dr. Tylka's research program at Iowa State University is primarily the soybea...