Don't Guesstimate: Free Testing for Soybean Cyst Nematode (SCN) is Available
Quick facts about soybean cyst nematode (Heterodera glycines, SCN)
- In Pennsylvania, SCN has been confirmed in at least one field in 12 counties.
- SCN is considered the most damaging soybean pathogen in the United States and Canada.
- The nematode can go unnoticed for many years; therefore, a proactive approach to SCN management requires nematode soil testing, even when the crop looks healthy.
- Potential yield losses associated with SCN infestation can reach 50%.
- The nematode survives in soil for many years, even without a host.
- Long-distance dispersal of SCN occurs via the movement of soil and infected roots that carry cysts and eggs.
How do you know if SCN is present in your fields?
Scouting and soil testing are the two methods for determining whether SCN is present in a field.
Scouting can be done six weeks after planting by digging out roots with a shovel and looking for SCN females. These can be seen with the naked eye and appear as small (1/32 inch), white, lemon-shaped structures along the roots (Figure 1-3).
Soil testing is another way to detect SCN and provides quantitative information about the population levels. Soil samples for SCN can be collected at any time during the growing season if nematodes are suspected of affecting your crop. Samples can be obtained by collecting soil cores at a depth of 6-8 inches in a zig-zag pattern. We recommend collecting at least 20 cores for areas of 20 acres or less. Samples can also target areas at high risk of introduction, such as field entryways, areas prone to flooding, low-yielding areas near buildings where equipment is stored, and high-pH areas. For each field, break up, combine, and thoroughly mix the soil cores in a bucket. Place at least two pints of soil in a sealable bag. Keep the samples away from heat and direct sunlight, and refrigerate them (do not freeze them) until they are submitted to a nematology lab.
Penn State Extension’s Agronomy Team offers free plant parasitic nematode testing for soybean growers across the Commonwealth, thanks to the support from the Pennsylvania Soybean Board. To take advantage of this offer, before submission, ensure the samples are labeled with your name, phone number, email, address, field address or GPS coordinates, current crop, previous crop, and acreage. Write "for SCN testing" on or in the shipping box.
Send the samples to:
Dr. Dilooshi Weerasooriya
361 Science Drive, Room 206A
University Park, PA 16802
If you have questions about the free testing program, feel free to contact Adriana Murillo-Williams (axm1119@psu.edu, phone 814-359-7483), Paul Esker (pde6@psu.edu), or Alyssa Collins (aac18@psu.edu). You can also contact your local Penn State Agronomy Extension Educator for more information about the sampling program. For more information about SCN, visit The SCN Coalition website.
