By Adriana Murillo-Williams and Paul D. Esker et.al
Spring is here, and farming operations are ramping up. If you are a soybean grower, this is also an appropriate time to take soil samples and have them tested for soybean cyst nematode (SCN, Heterodera glycines). The good news is that the Penn State Extension-Agronomy Team offers free plant parasitic nematode testing for soybean growers across the Commonwealth, thanks to the support from the Pennsylvania Soybean Board.
Quick facts about SCN:
- Considered the most damaging soybean pathogen in the United States and Canada.
- Potential yield losses associated with SCN infestation can reach 50%.
- The nematode can go unnoticed for many years; therefore, a proactive approach to SCN management requires soil testing for nematodes, even when the crop looks healthy.
- The nematode survives in soil for many years, even without a host.
- Long-distance dispersal of SCN occurs through the movement of soil and infected roots carrying cysts and eggs.
In Pennsylvania, SCN has been confirmed in 9 counties (Figure 1). The current distribution indicates that SCN is inching its way into the Commonwealth.
How do you know if SCN is present in your fields? Scouting and soil testing are the two ways to determine if SCN is 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 2).
Soil testing is another way to detect SCN and provides quantitative information about the population levels. Soil samples for SCN can be taken anytime 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 20 acres or smaller areas. Samples can also target areas of high risk of introduction, like field entryways, areas prone to flooding, low-yielding areas near buildings where equipment is stored, and high pH areas. For each field, break, combine, and thoroughly mix the soil cores together in a bucket. Place at least two pints of soil in a sealable bag. Keep the samples away from heat and direct sunlight and put them in a refrigerator (not the freezer) until they are submitted to the lab. 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.
If you want to take advantage of the free nematode testing, send the samples to:
Penn State
Dr. Dilooshi Weerasooriya
361 Science Dr., Room 211
University Park, PA 16802
Source : psu.edu