The latest on SCN risk to soybean growers and best practices to manage the pest

Soybean cyst nematode (SCN) is not a new challenge for growers, but how to manage it effectively is an increasingly important conversation. As a serious threat to soybean production across the U.S., SCN populations can multiply rapidly and significantly reduce yields in just one season if left unmanaged.

Untreated SCN can also interact with other soilborne pathogens, causing even more yield loss by:

• Stunting roots
• Increasing susceptibility to brown stem rot and sudden death syndrome
• Reducing the effectiveness of nitrogen fixation
• Disrupting vascular function

So what does proper management look like? According to Dair McDuffee, Seed Treatment Specialist at Valent U.S.A., the fundamentals of SCN management remain the same.

“Proper management starts with varietal selection, cultural practices and seed treatments to enhance protection,” McDuffee says.

The question is how growers can take a fresh look at those steps today.

Varietal selection and genetic components

The first step in any season-long SCN management program is seed selection.

One of the most common ways to manage SCN in soybeans has been through the PI 88788 source of resistance. McDuffee says SCN populations are increasingly adapting and gaining the ability to reproduce on soybeans with that genetic source.

“It has worked well for so long, but as resistance continues, growers need to be prepared,” he says.

To address these resistance concerns, McDuffee recommends an integrated pest management (IPM) approach to SCN.

“Active management is going to be the difference in preventing and controlling SCN,” he adds.

Practices for protection

Once a field is infested with SCN, the pest cannot be eliminated. However, populations can be managed with the right strategy.

Pre- and postseason

According to McDuffee, one of the most important times to act on SCN is in the fall. He recommends testing fields planned for soybean planting the following year so growers understand their nematode pressure before the season begins.

After harvest, practices such as rotating resistant varieties, rotating to non-host crops and properly managing host weed species can help slow population buildup in infested fields. Cleaning equipment between fields can also help prevent SCN from spreading to uninfested acres.

In-season

In-season management can be more challenging.

“The damage rarely shows during the season. You can have two fields look exactly the same, but one can yield anywhere from 5 to 20 percent less if it has a large and active nematode population,” McDuffee says. “Since there are no obvious signs of infestation, growers may not be aware of the damage, which is why it is important to scout throughout the season.”

Stunting, yellowing and early crop maturation can all be symptoms of SCN, but they are often mistaken for other issues.

Seed treatments

Using multiple modes of action early in the season can help preserve SCN technologies that are under pressure from resistance.

“In almost all cases of resistance, bringing in multiple modes of action early can extend the life of those technologies under threat,” says McDuffee. “Until more progress is made, PI 88788 is our best defense against SCN, and better overall management is key to keep it working harder and longer in your field.”

Seed treatments can play an important role in that approach. Products like Aveo® EZ nematicide from Valent U.S.A. can help growers take the next step in managing SCN through IPM. Aveo EZ is a stand-alone biological seed treatment that colonizes the root and grows with the plant from the start for season-long protection.

Taking a fresh look at SCN management plans can help growers stay ahead of resistance issues and protect yield potential. For more information on building an integrated SCN management plan, visit thescncoalition.com.