Soybean Cyst Nematode Map

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is an important, yield-limiting pest of soybean. This map shows the distribution across soybean fields in the U.S. and Canada.  First detected in North Carolina in 1954, SCN is now detected in all soybean-producing states and most Canadian provinces. A highlighted county indicates at least one confirmed SCN-infested field; management decisions should be made field by field. 

Among field crops, SCN reproduces only on soybean. Monitoring nematode distribution helps identify areas needing scouting and management. This is especially important as yield losses can occur without visible aboveground symptoms. Soil sampling is the best way to confirm SCN presence and determine population density.

Yield loss depends on cultivar susceptibility, nematode population density, and soil texture. Management focuses on reducing nematode populations or protecting soybean roots. Rotating with non-host crops, such as corn, grain sorghum, cotton, or peanut, can reduce nematode densities, but not eliminate SCN, which can survive for several years without soybean. Host plant resistance can reduce nematode populations and improve yield. However, many SCN populations now reproduce on PI 88788-resistant varieties, which dominates the U. S. and Canada soybean genetics. Other sources like Peking are effective but less available. Knowing SCN densities and its ability to reproduce on specific resistance sources is important. Nematicides can protect seedlings from infection and should be paired with resistant varieties for season-long protection.