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The pest is already widespread in most of Ohio and southern Michigan.

Chris Torres, Editor, American Agriculturist

February 8, 2021

4 Min Read
Soybean cyst nematode
SOYBEAN KILLER: Soybean cyst nematode is considered the No. 1 pest of soybeans globally, causing yield losses of about 100 million bushels a year in the U.S. alone.John Obermeyer, Purdue University

Soybean cyst nematode is in much higher numbers in the Northeast than previously thought, according to a recent report by the SCN Coalition.

New York state had 29 additional counties report soybean cyst nematode in the coalition’s 2020 survey, easily the highest increase of any state in the nation. Overall, the survey showed 55 additional counties in 11 states reporting new infestations.

The 2017 survey showed one county in New York — Cayuga — with reported infestations.

Lancaster County is the lone county in Pennsylvania showing infestations, according to the survey, but that number is likely being underreported. Paul Esker, a plant pathologist at Penn State, says the nematode has also been confirmed in neighboring York County and has tentatively been confirmed in three other counties pending follow-up testing.

The state runs a soil sampling and testing program that’s free to farmers and is funded by the Pennsylvania Soybean Board.

Soybean cyst nematode is already widespread in most of Ohio and southern Michigan. One additional county in Michigan was added to the survey’s count after reporting infestation.

Gary Bergstrom, a plant pathologist at Cornell University, says the increase in New York is likely the result of more testing done since the first infestations were found in 2016.

“You would just look at that from the surface and say it exploded. I think our investigation exploded,” he says.

Bergstrom says he’s not shocked at the additional number of counties reporting soybean cyst nematode, as soybeans have become a more prevalent crop. “When I started working with soybeans in the 1980s, there was only 10,000 acres. Now, it’s 300,000 acres in the state,” he says.

High stakes, few treatment options

Soybean cyst nematode is considered the No. 1 pest of soybeans globally, causing yield losses of about 100 million bushels a year in the U.S. alone. 

Testing, rotating fields away from soybeans, planting SCN-resistant soybeans and using nematicide treatments are the four recommendations from SCN Coalition for managing the pest.  

But all of these come with caveats. Testing is most beneficial in fall when the nematodes are at their highest numbers and most likely after they’ve done most of their damage.

map of counties with soybean cyst nematode

The counties shaded in blue are the newest counties that reported soybean cyst nematode in the SCN Coalition’s 2020 survey. New York state had 29 counties report soybean cyst nematode in 2020, the highest increase of any state.

SCN-resistant soybeans have been around for many years, but they’re not as effective as in the past since the source of resistance — the PI88788 trait — is in nearly all SCN-resistant soybeans. As a result, nematode resistance has been found in the Midwest.

Syngenta has two new soybean varieties sold under its NK and Golden Harvest brands that feature a new trait, PI89772, for soybean cyst nematode. But their availability is limited, as are soybeans with the Peking resistance trait, another potential control option.

Nematicide bean treatments are available, too, but again you have to do some research to decide if it justifies the extra cost to apply it.

Testing, testing, testing

Soybean cyst nematodes survive in the soil as cysts full of eggs. They move from farm to farm on equipment or farm tires, so the risk increases if you’re farming in multiple fields that aren’t contiguous, or if you hire a custom operator who farms multiple fields.

The pests usually are at low populations early in the season, Bergstrom says, but they can quickly multiply. One cyst can have more than 300 eggs. Bergstrom says that it takes three weeks to go from one generation of eggs to a second generation of eggs, and in one growing season, depending on conditions, you can get up to six generations.

They’re even more problematic in low-lying, wet areas, he says, because they can navigate through the soil in water.

The population will increase during the growing season depending on conditions, Bergstrom says, but the highest numbers will be in fall, and this is the best time to dig up samples and do some counts.

Testing for nematodes is done by counting the number of eggs per cubic centimeter of soil in a sample, usually half a cup, he says. “Moderate” population is anything greater than 2,000 eggs a sample. Anything greater than 12,000 eggs is considered a “high population.”

Yield losses from soybean cyst nematode range anywhere from 15 to 30 bushels per acre, Bergstrom says.  But even if the pest were to grow exponentially in the region, Bergstrom doesn’t think the per-acre losses will be as severe as other areas because of the crop rotations growers already use.

Like many other things, good management is key.

“Really, there's no magic wand. We really need an integrated approach to use these good agronomic practices," Bergstrom says.

“It’s pretty uncommon to find soybean after soybean [in New York], but having said that, we dare not be too smug because I do see a trend toward adopting a more Midwest-type corn-soybean rotation,” he says. “Our ace card is the rotations.”

About the Author(s)

Chris Torres

Editor, American Agriculturist

Chris Torres, editor of American Agriculturist, previously worked at Lancaster Farming, where he started in 2006 as a staff writer and later became regional editor. Torres is a seven-time winner of the Keystone Press Awards, handed out by the Pennsylvania Press Association, and he is a Pennsylvania State University graduate.

Torres says he wants American Agriculturist to be farmers' "go-to product, continuing the legacy and high standard (former American Agriculturist editor) John Vogel has set." Torres succeeds Vogel, who retired after 47 years with Farm Progress and its related publications.

"The news business is a challenging job," Torres says. "It makes you think outside your small box, and you have to formulate what the reader wants to see from the overall product. It's rewarding to see a nice product in the end."

Torres' family is based in Lebanon County, Pa. His wife grew up on a small farm in Berks County, Pa., where they raised corn, soybeans, feeder cattle and more. Torres and his wife are parents to three young boys.

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