Common Corn Nematode Characteristics

August 3, 2009
ICM News

By Greg Tylka, Department of Plant Pathology

Awareness of and interest in corn nematodes seems to be growing along with the crops this season. Growers and agronomists are asking lots of good questions about how nematodes feed on corn, what soils they prefer, how much corn yield loss they cause, etc.  Answers to those questions can be confusing and frustrating because there are more than a dozen different types of corn nematodes and the different species vary in their biology and behavior. The table below lists the basic characteristics of different types of corn nematodes.

* The damage thresholds listed in the table above are expressed as numbers of nematodes per g of root for lance and lesion nematodes; all others are numbers of nematodes per 100 cc soil.

These damage thresholds were established in the 1970s and 1980s and have not been verified with modern corn hybrids. The thresholds should not be considered absolute values for modern corn production systems. Also, threshold values will vary among states and universities; the values presented are those used by Iowa State University.


Greg Tylka is a professor of plant pathology with extension and research responsibilities in management of plant-parasitic nematodes. Tylka can be contacted at or by calling (515) 294-3021.  

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 3, 2009. 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...