SCN Females Now Visible on Soybean Roots

June 22, 2016
ICM News

The first generation of soybean cyst nematode (SCN) females is now visible on the roots of soybeans growing in SCN-infested fields in Iowa. The SCN females, which contain 250 or more eggs each, are white and about the size of a period at the end of a printed sentence (Fig. 1). The females are much smaller and lighter in color than nitrogen-fixing nodules, which are the color of the roots.


Figure 1. Adult SCN females (small, white objects) on the roots of a resistant soybean cultivar.

Digging roots (not pulling) and closely looking for SCN females is a simple, yet effective, way to check fields for the presence of SCN.

Unfortunately, resistance-breaking populations of SCN are somewhat common in Iowa and throughout the Midwest these days. Checking the roots of SCN-resistant soybean cultivars for SCN females is a good way to gauge if the resistant cultivars are not controlling the nematode. Seeing a few SCN females on the roots of a resistant soybean plant would not be cause for great concern.

Dig and look at roots from multiple places throughout various parts of the field. If SCN hasn’t been found in a field previously, high risk areas for initial infestation of fields include near the field entryway, in low spots, and along fence lines where windblown soil accumulates (Fig. 2).


Figure 2. Areas in a field where infestations of SCN may likely be found first.


More information about the biology and management of SCN is available at and


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 June 22, 2016. 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...