Soybean Cyst Nematode (SCN) should be top of mind as farmers make 2025 input decisions. SCN is in the top 5 when it comes to consistent soybean yield robbers. Those bushels are often silently lost and can rob up to 30% of our yield without even showing visual symptoms. Lighter soils often show visual symptoms faster than beautiful black prairie soils, but in droughty years – we can see symptoms everywhere.
As a soybean farmer, your top priority for combating SCN in your fields should be selecting varieties that have resistant traits bred into them. This is a no-brainer, right? But often SCN traits is not the lead conversation topic when picking out those next field winners.
Two Trait Options Available
There are 2 traits to choose from when arming yourself against SCN. PI 88788 trait represents over 90% of soybean varieties on the market. Peking was introduced in the late 1950’s, long before PI 88788. Peking varieties have had a hard time keeping up with yield until now. With new gene insertion techniques used today – Peking varieties are starting to show favorable yields, in comparison to the PI88788.
In fields with SCN resistance to PI 88788, current Peking varieties are outyielding PI 88788 varieties because Peking covers different Races of SCN. In other words, the Peking trait has not built-up resistance yet, and because of that, we are seeing a yield advantage. Both of these traits cover 8 races of SCN but they are not all the same. They are both resistant to Race 3 which is the most common in Iowa but only Peking is resistant to Race 5 which is becoming more widespread in our region. To see which variety has each trait, click here: SCN – Resistant Soybean Varieties and Trait Package.
It’s important to know, due to the breeding process of soybeans, not all PI88788 gene resistance is the same in every soybean variety/product. In other words, a variety with PI 88788 may not provide the same SCN resistance as another variety with PI 88788, so rotating varieties even with the same resistance trait will likely be beneficial to reducing yield loss from SCN. Similar in humans – we might all get a cold, but we might not tolerate it the same.
More Protection is Better!
IleVo seed treatment has been a big help in the fight against SCN. IleVo is not a silver bullet, but it is an affordable insurance policy that helps protect your soybeans from infection from Sudden Death Syndrome as well as SCN. SCN and SDS typically are found together, they both infect through soybean roots and cause damage in some cases without even showing foliar symptoms.
A meta-analysis from 200+ field trials shows a 4.4 bu/a increase and a 35% reduction in visual leaf symptoms. If your field has had with a history of SDS and you are battling SCN too, then talk to a Liqui-Grow Agronomy Field Advisor to get Ilevo on those soybeans for 2025!
Figure 2: Liqui-Grow Treated Soybeans
New Ways to Control SCN Coming!
A new resistance trait from BASF called Nemasphere is expected to be available to farmers in 2028/29. This will be the first transgenic trait available for SCN and this trait shows an 8% yield advantage over current varieties from the last 8 years in testing.
Natural vs. Transgenic
Both PI 88788 and Peking are native traits meaning it was natural resistance that was discovered within a soybean line and then breed into other soybean lines, which is why you don’t always see consistent results in resistance. A transgenic trait, as is the case with Nemasphere, can easily be inserted into more varieties faster with more consistent results (think Bt in corn). This novel trait will be available in their E3 platform.
Do you have a SCN population?
Liqui-Grow can soil sample for SCN and determine a range level of SCN population in each area. As a disclaimer, sampling for SCN is highly variable within a field but without sampling it’s just a shot in the dark as to how big of a problem SCN may or may not be in your fields. The best time is after the combine rolls before it freezes up, so if you are interested in SCN Sampling, don’t delay – call your Liqui-Grow Agronomy Field Advisor today!
Your sampling results will be in egg counts. Iowa State recommendations are if you are at 16,000 eggs/100cm3 or higher than you need to be rotating resistance traits and rotating crops. SCN can survive for many years in the soil so 1 year of corn rotation can help but likely won’t reduce populations. As with any pest, breaking up the rotation is a great way to mitigate and decrease populations. An ideal scenario would be to rotate to alfalfa for a few years or corn for 5+ years. Which can also create pest challenges too.
Questions? Give us a shout!
Text us at 564-220-2508 or email questions@liqui-grow.com.