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Soybean Cyst Nematode

Source: Craig Grau, University of Wisconsin
Source: University of Missouri
Source: University of Missouri
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Heterodera glycines
The soybean cyst nematode (SCN) is considered the single largest cause of soybean yield losses nationwide.  After four years of intensely surveying field soils in 17 counties from western through northern NY counties, the nematode was identified for the first time in Cayuga County in 2016.  Identifying and diagnosing SCN damage can be challenging, because aboveground symptoms may be vague or similar to other abiotic stresses, including stunting and chlorosis.  Belowground symptoms include discoloration or necrosis of roots and reduced nodulation.  The females may be visible on roots as very small white or yellow lemon-shaped cysts, and are easily distinguishable from nodules.  This pest was expected to be found at some point in New York soils, as it has been documented in areas of Canada adjacent to Niagara, St. Lawrence, Franklin, and Clinton Counties.  However, low levels of the pest can be difficult to identify in soil samples, and may require multiple years of sampling before the pest population reaches a detectable level.
 
We should continue to be vigilant in our continued search for the likely more widespread distribution of this potentially devastating pest throughout NY.  Systematic research survey efforts will continue to identify the full distribution of SCN in NY.  Soil sampling for SCN analysis is recommended for growers who suspect infestation, and this service is available through the Plant Disease Diagnostic Clinic at Cornell University and other state and commercial laboratories.  Because the nematodes are very persistent in the soil, and have a complicated race structure, an integrated management approach is recommended.  Management practices include crop rotation, planting race-specific resistant varieties, nematicidal seed treatments and cultural practices that reduce plant stress and optimize plant health and yield.


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