Soybean cyst nematode
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 (2014-2016), the nematode was identified for the first time in Cayuga County in 2016. A Cooperative Agricultural Pest Survey (CAPS) in 2019, funded by NYS Dept. of Ag. and Markets, identified seven more positive fields in six additional counties. In 2020, additional testing for 100 fields was funded by NYS Dept. of Ag. and Markets and NY Soybean Checkoff dollars. The map above outlines survey efforts and results. We hope to receive continued funding for these surveys to provide free testing to growers who suspect SCN on their farms. Please work with your local Cornell Cooperative Extension specialist for more information on how to participate in funded SCN testing, or how to scout and test for this pest on your own.
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 adjacent states and provinces. 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 be vigilant in our continued search for the likely more widespread distribution of this potentially devastating pest throughout NY. Systematic survey efforts will continue to identify the full distribution of SCN in NY, and reveal the population levels of this pest we are dealing with. Soil sampling for SCN analysis is recommended for growers who suspect infestation, and this service is available through a number of state and commercial laboratories. We recommend a lab that specializes in this testing and can provide egg counts, such as SCN Diagnostics. 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 and rotating race-specific resistant varieties, nematode-protectant seed treatments and cultural practices that reduce plant stress and optimize plant health and yield.
In addition to Cornell's efforts in NY, the Soybean Cyst Nematode Coalition is a diverse group of University researchers, Extension specialists and agricultural company representatives who are concerned about the evolving threat from soybean cyst nematode. Just like the first SCN Coalition from 1997, they’re encouraging growers to Take the Test. Beat the Pest. What’s different this time? Because SCN is becoming resistant to the PI 88788 source of resistance (used in more than 90% of resistant varieties), they’re encouraging growers to “Know Your Number” and actively manage SCN. Their goal is to decrease SCN populations and increase yield potential. We highly recommend that you visit their website for additional information, resources and recommendations.