Horacio Lopez-Nicora

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66 appearances 1 recordings 1 series first heard Mar 2025 last heard Mar 2025

Horacio Lopez-Nicora’s voice in public audio — every appearance, attributed to the second.

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Farm4Profit Podcast · Soybean Cyst Nematode: The Silent Threat Stealing Your Yield · 3 Mar 2025 podcast

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?

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.

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.

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.

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.

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.

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.

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.

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.

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.

And therefore, the search for new sources of resistance, for understanding better mechanisms of resistance, and maybe combining it with other

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

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?

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.

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.

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,

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?

You have more root for fewer nematodes, and each one can complete a life cycle in one month and lay on average 250 eggs.

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.

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.

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