In the Pod: Soybean Updates

Bruce Sundeen: 00:00

You're listening to In The Pod, soybean updates, a weekly trek into the latest soybean information from NDSU Extension. SCN or soybean cyst nematode can really take a bite out of soybean yields, But why talk about it at this time of the year? Wade Webster, NDSU Extension plant pathologist, has the details. Wade, what exactly is SCN?

Wade Webster: 00:23

SCN is a small microscopic roundworm that lives in the soil. They target specifically soybeans, and then they can also target dry beans as well. We don't have other crops that are susceptible to SCN, but when these things are present, they can be quite damaging. Wade,

Bruce Sundeen: 00:41

what kind of damage are we talking about?

Wade Webster: 00:43

Yeah. So these SCN, they are parasitic obligate pathogens or what we call them. So what that means is that these worms are not gonna kill the plant off, but they are going to suck the energy, suck the resources out of those soybean roots. Now it does this by forming a specialized structure called the syncytium that puts all the energy from that plant and sources it, pushes it into those worms. So by doing that, these soybeans are gonna have reduced energy and resources for their own growth, and we could see up to 30% yield losses in these particular areas with high SCN. Now, again, because of this, we're not gonna see those plants dying off, but we may see stunting or in severe cases, some slight yellowing on those soybean plants. And so these are areas that we would be wanting to pay attention to when sampling for SCN.

Bruce Sundeen: 01:35

So mostly, it takes a hit on yield. Right?

Wade Webster: 01:38

Yeah, so we see a hit on yield. We don't see any reduction or large reduction in quality due to SCN, but those seeds are going to be smaller. Potentially, those plants are gonna have less potential or yield potential on them because of these SCN worms. There's, again, zapping that energy out of the plant.

Bruce Sundeen: 01:56

Wade, what's the sampling program?

Wade Webster: 01:58

Since 2013, NDSU, in partnership with North Dakota Soybean Council, has had an SCN sampling program that's available to farmers in the state of North Dakota that allow them to sample their fields to identify if SCN is present and at what levels. Now this program is performed through AgVise, but, again, these samples are completely free for yourself to submit, and then you get those numbers back to you so you understand what those levels look like in particular fields of interest.

Bruce Sundeen: 02:28

Wade, why is it important at this time of the year?

Wade Webster: 02:31

Yeah. So we're talking about SCN at this point in the season because SCN is capable of causing impacts the entire growing season, and these worms are reproducing throughout the entire growing season. So if we're thinking at the end of this year, this is when SCN are gonna be at their peak population. So when we think about sampling, we wanna understand when those populations are at its highest so that we can track year to year. Now we can also sample in the middle of the summer or in the spring, but those numbers are going to be skewed slightly because of slight reduction in those populations due to natural causes. If we go out and sample over a couple of different years, we just wanna remain consistent. But, again, it is recommended that we sample at the end of the growing season either right at or right after soybeans are harvested.

Bruce Sundeen: 03:20

Wade, what about management? Is there anything producers can do right now?

Wade Webster: 03:24

At this point in the season we are not able to do anything from management perspective, but what a lot of individuals or farmers are gonna be doing right now are making seed selections for the next season. So when we think about SCN, the seed source of what we call either eight eight seven eight eight or peaking sources of resistance are gonna be very important. And so using these resistant sources, those farmers should be rotating between those different sources so that we are increasing the diversity of selection pressure that's put on those SCN populations. What we don't want is to use the same source of resistance year over year. Otherwise, those SCN will adapt and overcome those sources of resistance. So, again, rotating between the different sources of resistance is incredibly important going into this next season.

Bruce Sundeen: 04:13

Thanks, Wade. Our guest has been Wade Webster, NDSU Extension plant pathologist. You're listening to In the Pod, soybean updates, a weekly trek into the latest soybean information from NDSU Extension supported by the North Dakota Soybean Council.