Soybean cyst nematode (SCN) and sudden death syndrome (SDS) are two of the biggest emerging problems on the soybean battlefield right now, and there’s a lot of bad news to be reported.
SCN is a worm that lives in roots that was first found in the southern United States in the early 20th century. It likely came over from Asia on some ornamental rootstalk, but no one can be sure. Its first occurrence in Canada was in Ontario in 1988. As soybeans become even more prominent, so does SCN.
SCN is one of the only nematodes that have a life stage visible to the naked eye. It’s the female nematode that sticks out of a root when she is full of eggs, forming a cyst. On average, you get a 10 to 15 per cent loss in yield and you can never even see symptomology. When symptoms do show, they come in the form of chlorosis, leading to stressed plants and nematode pressure.
Although not directly related, SDS and SCN can be a lethal combination if you have both. SDS is caused by a specific strain of fusarium that causes a toxin to form in the roots early in the season. It moves up the plant and into the foliage when the plant translocates water late in the season. Once it’s in a field, it’s there permanently and robs you of yield each year, regardless of whether you see symptoms. SDS can be totally devastating to a crop.
Thankfully, I can report that there’s positive news to be shared. We’re learning more about these two problems, and we have effective tools to fight these soybean enemies.
An important one is a new Group 7 active in soybeans called fluopyram (the key active in ILeVOTM seed treatment), the first seed treatment in Canada registered to protect against SCN and SDS. Having this new tool is making all the difference in the battle against these two new emerging threats.
Other weapons include the common sense basics: choose varieties with built-in SCN and SDS resistance. Crop rotations are also crucial for fighting SCN. Currently, there’s no way to rotate out of an SDS problem.
While both of these problems will only become worse as time goes on, we can manage and try to keep ahead of them with new tools currently available.