Soybean Cyst Nematode: Part 1 - Behind the Headlines

Soybean cyst nematode (SCN) is a major disease that is limiting yields across nearly all soybean-producing acres. SCN has been spreading across the U.S. since it was introduced in the 1950s but has only recently reached the headlines with “PI 88788” and “Peking” becoming common coffee shop chatter. In this article, I’d like to propose a few reasons for the recent hype around this disease and my insights into the future of SCN management.  

📸: BASF employee/Featuring a close-up shot of soybean root system infected with soybean cyst nematode (SCN).

Why Soybeans Now? Rising Importance & The SCN Spotlight

1. Soybeans rise in relevance. Although we plant over 80 million acres in the United States, soybeans have been considered a rotational crop and haven’t received the same management attention as our beloved corn crop. Soybeans are benefiting from a strong demand for plant-based oils to supply sustainable aviation fuel. Also, soybeans are benefiting from decades of genetic and trait research that has only recently come online. Growers have been increasing soybean yields by adopting elite genetics, doing a better job of controlling weeds, and planting earlier. The next frontier for higher-yielding soybeans will be reducing yield loss from pests like SCN.
2. Something new to talk about. “Tell me something old,” said no one ever. We want to hear what is new, and Peking fits the bill. To be clear, there is nothing new about Peking; it was first collected by the USDA in 1906. For reference, PI88788 was collected in 1930. As SCN gained relevance in the 1980s, PI88788 was deployed as a source of resistance and has remained the predominant source ever since. Peking has lagged in soybean breeding programs as a smaller percentage of crosses will carry the resistance forward, resulting in slower genetic yield gain. Improvements in genetic markers and years of dedicated breeding efforts have made more Peking varieties commercially available. As a “new” tool against SCN, the industry is beating the drum and stirring up the hype.
3. Recent drought increases SCN impact on yield. The previous decade went down as the wettest on record, while the last three seasons have been drought years. Damage from soybean cyst nematode is favored by hot and dry conditions. The last three seasons have allowed for greater SCN reproduction, and the damage to roots has resulted in yield loss. This has been a contributing factor in the headlines of variety trials showing the yield advantage of the Peking source of resistance.  

Beyond the Hype: Long-Term SCN Management Strategies

There are a lot of reasons behind the recent hype surrounding Peking in soybean. As a soybean agronomist, I’m grateful for the attention given to a significant pest and hope the increased awareness will influence lasting change. A major concern with a rapid adoption of Peking is developing resistance. Due to the mechanism of protection, Peking is less durable than PI88788. There is a real concern that the level of resistance to PI88788, which has taken decades to develop, could occur in a few short years if we are over-reliant on Peking alone. So, if Peking isn’t a silver bullet, how should we manage SCN? 

Dive Deeper into Managing SCN in Part 2! Managing Soybean Cyst Nematode.

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