Campus Units

Plant Pathology and Microbiology

Document Type


Publication Version

Published Version

Publication Date


Journal or Book Title

Plant Health Progress




In the United States and Canada, the most damaging pathogen of soybean, Glycine max, is the soybean cyst nematode (SCN), Heterodera glycines. Plant health professionals working for universities and state and provincial departments of agriculture in the United States and Canada are queried periodically about counties and rural municipalities that are newly known to be infested with SCN in their states and provinces. Such a census was conducted in 2020, and the results were compared with results of the most recent survey, published in 2017. Between 2017 and 2020, 55 new SCN-infested counties were reported from 11 U.S. states. Also, 24 new SCN-infested counties and rural municipalities were identified in the Canadian provinces of Manitoba, Ontario, and Quebec. A map of the known distribution of SCN in these two countries was updated. The results reveal steady expansion of the distribution of SCN throughout the United States and Canada, and the pest almost certainly will continue to spread among and within soybean-producing areas of these countries in the future. Therefore, continued scouting and soil sampling for detection of new SCN infestations are warranted as the first step toward successfully managing the pathogen.


This article is published as Tylka, Gregory L., and Christopher C. Marett. "Known Distribution of the Soybean Cyst Nematode, Heterodera glycines, in the United States and Canada in 2020." Plant Health Progress (2021). doi:10.1094/PHP-10-20-0094-BR. Posted with permission.


The authors retain the copyright for the map (Figure 1) and the animated series of maps (e-Xtra gif). All other content is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2021.

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The Authors



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