Horacio Lopez-Nicora
Appearances
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yeah, that's a great question. And so the nematode will penetrate the root. So sometimes we think, you know, that resistance will avoid the nematode penetrating the roots, and that's not the case. So you put a tomato root and the soybean seed nematode will go inside that root. It will penetrate.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
It will use the stylet, which is like a needle that it has on the head, to break those cells and migrate to the vascular cylinder. When the nematode penetrates a susceptible soybean, and does this migration to the vascular cylinder to establish this feeding site, it will probe cells with that stylet. It will release effectors, right, to engage in that interaction of host pathogen.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
When that happens, the nematode becomes sedentary and cannot move anymore. And that's how it's going to complete its life cycle. The susceptible soybean will feed the nematode for its entire life. Now, at one point, the males will regain this warm light condition, will get out of the root and will fertilize females. The males won't feed anymore. At least we don't have evidence that they feed.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
They will fertilize a female. This is a sexual obligate parasite, just like we are. We have to have sex to reproduce. Soybeans is nematode, have to have sex to reproduce. Now, this is very important because every sexual recombination means that there is a possibility to shift virulence, to adapt to new traits, to become more resilient.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So this is great from the perspective of the pathogen that can adapt very well. Now, what happens when we have a resistant soybean? the nematode will penetrate the root of a resistant soybean, will migrate to the vascular cylinder, will start probing those cells and engage in this interaction with this plant.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
As a matter of fact, the nematode will become sedentary because the nematode thought that it actually established that feeding site. Now, this resistant plant, once that happened and the nematode cannot move anymore, kills all the cells around the head of the nematode. which are supposed to feed the nematode, starving the nematode to death. I mean, this is very cruel, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
I don't know if these are time to talk about this event, right? I don't know who's listening to this show, but it's a very cruel situation, starving the nematode to death. We don't care, right? But that's how resistance works. That's how resistance works. Now, the nematode can adapt, like we mentioned, and overcome that.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And it happens just exactly how Dylan was mentioning, the overuse of the same source of resistance. I mean, PI88788, which has amongst the many genes, one log user is the ARCHAG1B, that confers a lot of resistance to the nematode, has been used for over 30 years. I mean, just think about telling someone, go and spray these same active ingredient to manage your weed for 30 years.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
We are going to exert a selection pressure and that's what we did. The population of the nematode that we could, that we were able to very effectively manage with PI-88-10-88 is not there anymore. The virulence profile shift to a different type. And that's the type that now prevails across the soybean producing region of North America. That's wild. So we're losing efficiency with PI88-1088.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
We identify other sources of resistance. So when we talk about PI88-1088, PI stands for plant introductions. These are horrible soybean plants that have traits that we like. We don't like to grow them. They grow horribly. very viney. As a matter of fact, you can have it in the house for like, like an ornament. I actually have it at home as a decorative plant, you know, but horrible.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
We can not grow it, but it has a trait that is resistant to soybeans. We can use it to introgress it in high yielding soybeans that we like to, to grow. Peking is another one. And there are seven that we know of that have resistant to soybeans. Right. Right.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Now, pekin is an alternative like we just mentioned, but we have evidence that if we overuse that, like we did with PI88-1088, we will lose that effectiveness very, very soon, even more so than PI88-1088.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
You know what? That's a great question, right? And these sevens are the ones identified as we screen for these germoplasms. We just go and we have access to these germoplasms of weird soybeans. And we test them against soybeans nematode. And then we can identify. Now, important thing is that they have to have different genes.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
mode of action, if you want to put it in a very simplistic way, that, you know, the genes associated with a resistance have to be different. And that's the case for all of this. And they appear in, you know, in chronological order. Beijing was the first one to be identified, PI88, 1088, the second one all the way to cloud.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Now, the question is, I'm only seeing to what's happening with the other one. In most cases, they're not easily introgress in high-yielding, high-producing soybean. In other cases, some of the populations of soybeans that we have have already developed the ability to reproduce on these sources.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And therefore, the search for new sources of resistance, for understanding better mechanisms of resistance, and maybe combining it with other
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
The most precise term that I would recommend, you know, to encompass all these products would be seed protectant. Because some are not strictly nematicides, right? By definition, nematicides is a product that will target that animal and kill it. In many cases, some of these active ingredients are fungicides in their origin, right? So fluopyram is an
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
excellent fungicide that, you know, in vitro has activity on egg hatching or the nematode itself, right? But then when we think about this integrated management and we think about our field having SCN, which is a big problem, that doesn't get rid of all the other pathogens that we also have in that field. And just enhancing that root health comes very handy when we use a seed protectant, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So we may be, like you mentioned Alevo, for example, it's great for SDS, sudden death syndrome. And we know that there's an interaction that may be going on between the nematode and that fungus. So that could give some extra protection there for the plant.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So the life cycle in general, it's one month. I mean, this is rough, right? You know, depending on the conditions you give it, it's going to be 27 days. It's going to be a little bit over a month. But in one month, you will have the female completing that life cycle, being fertilized and laying eggs. On average, 250 eggs. That's a field average.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yes, it's a plant parasitic nematode. That's how we're going to call it. And not only that, we can add obligate parasite. It requires a living root to survive and to reproduce. You take the nematode out of that root that it's feeding on, and it will not survive. You try to grow it on something that is not alive, you will not be able to grow it.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And that can happen three to four, maybe five times in one season, which is, you know, huge in the sense that we start with very low soybean cyst nematode. And that's a comment that I always get from my growers when we have conversations about this. I don't have to worry about soybean cyst nematode. I have very little soybean cyst nematode. And when you have low numbers of soybean cyst nematode,
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
for some reason, that relationship with the ability to reproduce very fast is inverse. So it's inversely related to the reproduction factor, which means the lower nematodes you have, the faster they will reproduce. In one season, that number can explode very easily. And it makes sense, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
You have more root for fewer nematodes, and each one can complete a life cycle in one month and lay on average 250 eggs.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
That's a great question. You know what? There's a gap in research in terms of survival of the eggs, but not only survival of the eggs, also the hatching mechanism, which is fascinating. The nematode, you know, those eggs within that dead female, when the female dies, it will enclose eggs within that female. And the dead female is what we call the cyst.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
It melanizes, it oxidizes, it becomes very protective of those eggs. And those can last for a long period of time. We're talking about 10 years or more. Wow. Now, the hatching process is one that we... I think still have more to learn. We know that there is a batch, a cohort of those eggs in the soil that will hatch when the temperature, you know, hits a little bit warmer, you know, point.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So, you know, you're getting to spring, coming out of winter, it's getting warmer, those eggs will hatch. There's another cohort that will only hatch if it smells soybean, if there is exudates of the host. And there's a third cohort, which is an enigma, which will hatch whenever they want. It's time dependent. You provide warm temperature, they don't hatch.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
In Ohio, we provide up to two samples free of charge for growers. They can submit a There are samples, and we'll process those for soybean cyst nematode, and then we'll report numbers of eggs per 100 cc of soil, cubic centimeters of soil.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yeah, and that's a great comment, Corey, because we have been trained as growers to pull samples for our soil test, soil lab nutrients, right? We do it routinely, right? That same soil sample, we can pull a soup sample and send it to a nematology lab. We collect it in the same way. that task that really going out and getting the soil sample is the most time-consuming part of doing it.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Once we have that, we can split that and send it to a soil lab for nutrient analysis and to a nematology lab to test for soybean cyst nematode.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So from a commercial soybean field, 27,000. So we usually get a couple of those every year. Yeah. And it's really hard to bring those levels down. And that's one of the, you know, best management strategies to actively sample and identify if you have soybean cyst nematode that you do, and then try to keep those levels low, which is easier than trying to bring higher levels down.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And you say 350, correct, Corey? Yeah, that's my highest. And that's great because I consider those low numbers maybe not even causing much damage yet. But then how cautious we need to be about that low level and how in one season it can explode if we feed that nematode a very susceptible soybean in a very conducive environmental condition.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And we have growers that engaged in, in these, uh, experiment that, that I proposed, uh, them, you know, they sample in spring before planting and they come with very low numbers. And then my request is let's go to the same site and sample again in fall and levels of 400 or 200, very low, um, by the end of that season were above that thousand levels that Dylan was talking about.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
That would be, that would be excellent. And maybe you guys can have us back, you know, we can do a part two after harvest.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yes, correct. For some reason, alkaline soil, higher pH soil, for some reason in those sites, the reproduction rate is higher. What would you say?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
That's a nice way to target where you're going to start sampling sometimes. It's like, where do I start? Should I just take our random cross-section sample? That's fine. But maybe you want to be strategic and have comparisons. What we normally recommend is entryways, areas where soil will move, either because of water flowing, high pH content,
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And then you can have multiple sites where you are evaluating. Using yield maps from previous year, it's another one. Most of my growers have come to realize that they had soybeans is nematode because we went to those low yielding spot that they have, you know, did everything and still continue yield low, right? So we took a soil sample, soybeans is nematode.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yep. Compared to 30 with higher numbers, yes, in that sense, right? And actually, this calculator is becoming very handy to move away from tables that talk about low, high, moderate, right? because it takes more into account certain aspects of Cory's field.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
I can take this question. It's a good one, because we get a lot of these questions, you know, and one of the comments that we receive is, I farm heavy soil, so I don't have to worry about soybeans as nematode. And we have a project with a master's students where we're purposely going and taking soil texture.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So we have a range of different texture, sandy to very heavy soils and everything in between. The sandy soil allows the the animal to move faster. And it does move in very, very short distance, right? It also creates more of additional abiotic interaction. So those soils will get dry faster, plants will stress faster, and you put that pathogen there and it cause more significant yield reduction.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Once the nematode hit the root, It doesn't matter if it's in a sandy soil or in a heavy soil. It will reproduce. So we may be delaying, you know, that dramatic yield reduction that we see in sandy soils when we plant in heavier soils with nematode. But when that population builds up and it's pretty much across, then we're in pretty much the same fate. Okay.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
No, from our conversation, I will caution planting as susceptible, right, in any instance, just because of how fast the nematode can reproduce. And the SCN Coalition, we have a very nice infographic of how explosive these populations can be when we provide a very susceptible cultivar. Now, like Dylan mentioned, most of our PI88-NAA, by definition, is already susceptible at
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
some degree to the populations of nematodes we have. But I think for the audience, there's a really easy way to remember a nice integrated management strategy, the triple R management to SCN. Rotate, rotate, and rotate. Rotate to a non-host. Rotate different soybean varieties. Don't feed this animal the same generic material because it will adapt And rotate sources of resistance.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And on top of that, sample your field so you know if you have it so you can monitor those numbers and consider acid protecting. Because you're going to have other stuff other than soybean disease nematode also threatening your soybean health.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yeah. Thank you for having me. My name is Horacio Lopez-Nicora. I'm the soybean pathologist and nematologist here at The Ohio State.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yeah. Yeah. No, that's a way to think about science and next research, Corey. I totally agree with you. And one thing that we were talking about, how excited we are of new products coming, one is nemasphere from BASF, for example. It's a transgenic soybean.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And what it does, it expresses this cryprosing, you know, like the BT, the BT that we know from exactly the same, but it's one that targets these nematodes. So... You just mentioned it. How can we do the same thing? And it's already out there. It's going to be hopefully available in 2028 pending registration and everything, right? But can we do something else?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Can we modify it in a way that those feeding sites now are producing only males or completely shutting down? And just create a lazy male.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Oh, this is a, this is yerba mate. This is like a tea is a South American tea. Very traditional in Argentina, Paraguay, Uruguay, parts of Brazil. Um, You put hot water, there's a filter straw here, and you just drink the tea, and it's highly caffeinated. The cup looks like it's got feet. It's a gourd.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
It's like a little pumpkin that you cut, and then you put little things so it doesn't trip over the table. That's a filter.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yeah. No, this is actually the tea. This is the tea here that you put. And then the straw has a filter.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Hierba mate. I mean, Madonna drinks it. Come on.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So, yeah, like Dylan mentioned, there's several hypotheses of how it's moving so fast because The fact that it's moving, it makes sense. We move soil around, it's going to move around. So equipment that we don't clean very well, it's going to move the nematode around. You know, it sticks to the soil and anything that can move that will move the nematode. But how did it? move so quickly, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
How did it expand throughout North America so quickly? And a different hypothesis is that it can also travel through that digestive system of these migratory birds. These may be picking, you know, roots and particles of soil that may contain those cysts, which are the dead females that contain the eggs. And these will survive through that digestive tract, and they will be dispersed.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
That's another hypothesis, right? But one thing that, you know, we were talking at the beginning is that, I mean, this is an animal, like us. It's an animal, and it penetrates the root system and overtakes the plant machinery, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
If we go and make thin cuts from those roots where the nematode is feeding, because it feeds from particular cells that it modifies, so it turns those cells into feeding sites. And if we make very thin sections and look it under the microscopes, those cells are completely modified, resembling transfer cells. I mean, these are not cells that we are supposed to find in the root system of any plant.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
They're cells that we're supposed to find in the embryo, in the seed. So the nematode is really taking control of the plant machinery and making it believe that in my root system, that's where you need to feed your progeny. I mean, of course, I'm making these extremely more simple than what it is, but we don't see symptoms.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Like Dylan say, we have beautiful soybean plant losing 30% yield, and we just thought we had the best season of our life. And we left, you know, on average, what, $300 an acre below ground?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
That's a great question. We have a physical damage, which is a penetration of the nematode. It has a stylet that we'll use to break into the cells and the root system, migrate to the vascular cylinder of the plant, where you have the phloem, where you have the xylem. So movement of water and nutrients are going up and photosynthates are coming down.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
And the nematode sets these feeding sites very close to that region. So double punch there, right? But more of the damage is caused by these modified feeding sites. And it's way more intricate than just saying, you know, it modifies a cell, right? There's evidence of research of, you know, taking control of hormonal system, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
So some of the major hormones like auxins will be up and down regulated. So it's fascinating, right?
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Yes, it's a plant parasitic nematode. That's how we're going to call it normally. And not only that, we can add obligate parasite. It requires a living root to survive and to reproduce. You take the nematode out of that root that it's feeding on and it will not survive. You try to grow it on something that is not alive, you will not be able to grow it.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Very differently than with other pathogens of soybeans that we deal with, right? You mentioned SDS, for example. It's caused by a fungus. That fungus can be easily grown in a media that is not alive. It's still a parasite. It can parasite the plant. but still you can grow it on a media that is not alive. Soybean is an obligate parasite.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
That's a great question. The mechanism of interaction is something that we are still trying to better understand. So the reports that we have and the evidence of interaction are... from very indirect observation. What does that mean? Well, when we have them both together, we see more SDS symptoms showing up.
Farm4Profit Podcast
Soybean Cyst Nematode: The Silent Threat Stealing Your Yield
Or SDS symptoms, which are those intervenial chloroses yellowing in between the veins of the leaf, show up earlier when we have a lot of nematodes. Understanding how that really happens, which is a mechanism, is still something that we're trying to figure out.