Strategic Farming: What's Bugging Your Corn?
Welcome everyone. This is Anthony Hansen with the University of Minnesota's IPM podcast series for field crops. Today, we have a special episode for everyone, bit of a bonus episode, so to say. Throughout this winter, we had a special series called the strategic farming, let's talk crops webinars. And these were a series of webinars put together every week sponsored by the Minnesota Corn and Soybean Growers Associations, where different researchers and educators would discuss different topics for about ten minutes of research they've had ongoing.
Anthony Hanson:And then they would field questions from growers and other egg professionals for the remainder of the time for at least about twenty minutes. So it was a good opportunity for growers to actually come and ask questions from across the state. On March 3, we had an episode especially related to IPM talking about corn insects or what's bugging your corn in 2021. In about the first fifteen minutes, both doctor Ken Ostlie and Bruce Potter discussed some of the current research that's been ongoing in about the last year. After that, so people were pretty interested in what was going on in the corn world when it comes to insects lately.
Anthony Hanson:This is the time of year when you're often sitting in the tractor wondering how the crop is going to do this year. Sometimes you don't want to worry about that as much you're thinking about it, but that's going to cross your mind at one point or another. So this will help you think about a little bit what might be happening or what you might want to expect. So let's tune in to hear what both Doctor. Ken Ostlie and Bruce Potter had to say about that.
Ken Ostlie:Good morning, everyone. I'm glad to be here. The focus today is on what's bugging us in terms of corn insects. It seems pleasantly distant ago that we were seeing scenes like this with more cold, brutal weather, and it probably has you thinking of excitement of seeing spring come, wondering what the cold did with insects. And so Bruce and I are going to share some different dimensions of that as we go through the next few minutes here.
Ken Ostlie:When we're thinking about prospective insect problems, it's important to keep in mind that we have five categories of insects out there that are pests. We have locals, these are primarily pests that are residing here. They overwinter here. And in general, they're fairly well adapted to the situation that we have in Minnesota. And in general, brief periods of cold weather like we had this year are not a big challenge to them.
Ken Ostlie:What we're going to see next summer potentially is just carryover from 2020, and what that ramifications that has as modified by weather in our cropping situation. We have opportunists that are weather related. Think of insects that are more problematic during drought. We have migrants, and these can't overwinter here. They come from more Southern locales.
Ken Ostlie:And because of the way the jet stream sets up, etcetera, and the long distance transport involved with these insects, we very seldomly know exactly what we're going to be getting. And so every year is kind of a surprise that way. Then we have adapters, and these are changing to practices. For example, reduced tillage, increased use of cover crops, for example, are changing the insect community that does best under those conditions. And then finally, have invasive insects, whether we're talking brown marmorated stink bugs, or Japanese beetles, or soybean midge.
Ken Ostlie:So, you know, there's lots of change every year, and that's one of the things that is very interesting, working in Minnesota on corn insects. And I'd have to say that I haven't been bored in the thirty five years that I've been working here. As we think about where the insects attacking corn, they come with a variety of targets that the insects are focused on. In general, the last few years, we've had very little in terms of stand reducers. The neonicotinoid seed treatments are doing a fairly good job on most of these in corn.
Ken Ostlie:We also have our key pests, the ones that we historically have considered managing in most years, and that's European corn borer and corn rootworms. But of course we know for the last twenty plus years, European corn borer has not been a significant issue. The last four, five years up until 2020, corn rootworm populations had diminished. Thinking about all these insects in terms of the five categories, we've got the migrants here are things like armyworm, fall armyworm, the cutworms, corn earworm. And we have new invasives such as brown marmorated stink bug, the Japanese beagle, for example.
Ken Ostlie:We have opportunists on some of those that we have dealt with in drought years include grasshoppers and spider mites. There's a variety of things that can be affecting the crop this year. I'm going to focus a little bit on what's our remaining key insect pest, which is corn rootworms. BT resistance continues to develop, weather management have reduced populations over the last few years. However, conditions were extremely favorable in 2020, and we saw populations build.
Ken Ostlie:And if you think of the seasonal play of what's going on with corn rootworms, We're in that winter survival period right now where the eggs are out there in the soil, and we'll see what the outcome of this temperature, cold temperature regime this year will be like. Then in the spring when those eggs hatch, there's a period where they're very susceptible to conditions, and that is when they're trying to find a root and get established in a root system. At that point, things like spring rainfall, the timing of planting can have big impacts on rootworm populations. Then they go through a larval competition period, and then finally, when the adults come out, you have weather that is essentially, potentially affecting egg laying. So think of this, when you think of this cycle, think about what's happened over the last year.
Ken Ostlie:In the 2019, we had excellent conditions for egg laying. Adults were able to persist in the field a fairly long time under mild conditions, been a very mild winter. And then in the spring, in contest to previous years, we didn't have as many inundated rainfalls, so we had an early planting as well, or more timely planting. And between those two things, colonization was very successful. And as a result, we saw dramatic increase in adult populations and good egg laying conditions last fall.
Ken Ostlie:So all that sets the stage for an increase in corn rootworm pressure this year. The big question, of course, is how are the winter conditions going to affect things? It's well known that certain temperatures are very catastrophic to corn rootworm eggs, however, they are laid in the soil and typically covered by some layer of snow, which acts as an insulating blanket. So the environment that eggs are actually experiencing is dramatically different from air temp. And this was Eric Lawson did this work and reported in his thesis in 1986 from Iowa State University.
Ken Ostlie:And basically he found that winter mortality in Western corn rootworm was linearly related to the amount of cold that those eggs experienced below freezing temperatures. And you may wonder, you know, in the past what's happened, we had a severe impact on corn rootworms in 1976, 1977, and from 2013 to 2014 winters. And you can see there that the soil temperatures are dropping into the negative teens, and even some cases, approaching negative 20. And in the next year, following this kind of winter, there was this dramatic decrease in Western corn rootworm populations. Basically though, Northern corn rootworms adapted here, as opposed to moving up from the Southwestern part of The United States.
Ken Ostlie:And so they're much more winter hardy than the Westerns are. So that sets the stage for what we're seeing this year. And I just grabbed some data from Waseca to illustrate the importance of snow cover, that air temperature got down to an average of minus 15 at one point in February. But if you look at soil temps, you see that they're relatively stable and only dipping a little bit below freezing. And you may wonder how in the world that can occur, and it's because there was a six to 12 inches layer of snow during this time period.
Ken Ostlie:And of course, we know fields don't necessarily keep the snow that's landed on them as it blows around in Western Minnesota, for example. So it all depends on what kind of snow cover is in the field or parts of the field when the temperatures get low. One of the challenges we've got in management, of course, is status of resistance. And what's changed over the last few years has been that Northern corn rootworms have now developed resistance to BT traits since they're verified in North Dakota and Minnesota. We're seeing increasing issues with SmartStack and Chrome under the heavier pressure that developed in 2020.
Ken Ostlie:We know that reports of performance issues also increased during that time period. The challenge with rootworms is always getting a handle on what's going on in the field. This is particularly difficult when you've got land, rental land changing hands, and if you haven't actually been able to get out in fields and take a look at populations. So you know, we're always encouraging stat counting. What's new with traits?
Ken Ostlie:We now have SmartStats Pro available that's now been approved in Europe. And so it's potentially available for growers as an option if they've got increasing issues with SmartStack or Chrome. We know that on the insecticide front, where we have some other options, Aztec is a higher concentration granule. You don't have SmartBlocks. Boxes looking at liquid systems, index and Ampex are two newer options.
Ken Ostlie:I think Ampex at this point doesn't have a full label, but it's one of the products that we've been looking at. The challenge, of course, is just managing the crop budget. Fortunately, it looks like prices for this fall are anticipated to increase, and that's going to take some of the burden off, but it's still wise to take a look at what your inputs are, and are you balancing risk versus the cost of essentially insurance to you. Well, that ends my portion of it. And I think that Bruce has some things he would like to share.
Speaker 3:Thank you, Ken. And Bruce, to lead you off, we have one question in registration that might play into a little bit what you'll talk about. One question is can one predict if or when conventional corn would cease to be a money saving management decision on a farm?
Bruce Potter:Alright. So, basically, the longer you've had fielding corn, the greater the potential for, increasing particular insect problems. And and one of those would be, European corn borer. Ken mentioned corn rootworms. So I guess the the only way to know for, to have a good feeling on on how things were are progressing is to do some good scouting.
Bruce Potter:In the case of European corn borer, we do a fall survey. Doctor Bill Hutchinson's lab leads this, and it's funded by the Minnesota Corn Research and Promotion Council. Before BT was adopted, you can see some pretty high populations. They're cyclical, of course. And, in '20, the last three years, 2018 teen through 2020, those populations are lower.
Bruce Potter:These are general observations. They're they're particular fields that that are economic in all these all these, years. But they're definitely, the overall populations are down. And based on the fall survey, it looks like damage is maybe a little bit down from from 2019. But the interesting thing we picked up on the survey this year, Anthony, was that, we're we're finding fields, particularly in West Central and Southwest Minnesota, where we had tunnels but didn't have any, overwintering larvae in them.
Bruce Potter:So I'm not sure if that's because of disease or not, or or another factor. So basically, you know, if if a lot of guys are starting to go because of corn rootworm is the big driver, starting to go through to a different rotation. And they're, where they can, they're throwing a year of soybeans in that corn to knock, knock corn borers back or corn rootworm back, and it's also knocking corn borers back in those fields as well. The difference between something like a corn rootworm, a European corn borer, is the corn borers will move between fields, so it's more of an area problem. And corn rootworms, Ken, I think will agree with this, are very field specific.
Speaker 3:I'm gonna go with a couple questions we're getting in chat right now. They're wondering about the geographic range of corn rootworm. What is that in the state, and are they capable of causing injury in Northwest Minnesota?
Ken Ostlie:Well, historically, you know, you had populations getting up as far as the Fargo Moorhead area, but in general, that was fairly low and infrequent percentage of fields that would have a problem up that high. However, the amount of corn on corn has increased significantly, and with kind of like warmer seasonal temperatures in general, there's certainly the potential for Western corn rootworm to increase at higher levels as we go farther north. And I think Northern corn rootworms, you can regard as kind of local, They're here, they can handle the temperature, soil temperatures. So are we going to see more problems? I think from a weather perspective, that could certainly increase.
Ken Ostlie:We know we're getting a little more variability in terms of winter temperatures, but in general, with the milder trends increasing, this could be a more prevalent issue as we go north.
Speaker 3:Thanks, Ken. Another question from the chat is Western corn rootworm specifically, has been capable of overcoming broadcast insecticides, BT rotation fairly quickly, and how likely and quickly will they be able to overcome RNAi?
Ken Ostlie:So RNAi is kind of unique in the sense that corn rootworms have never seen anything like that. And the particular pathway that they're trying to disrupt in RNAi is fairly specific to corn rootworms, and in fact, mainly the economic weed threatening corn rootworms. So think of it this way, there are other wild species of diabrata out there. They have found that they have gotten some colony development of resistance, and that's one of the reasons you see the RNAi added to our most effective blend of individual traits right now, which would be Smart Stacks. And so they're trying to buffer things and give it as long a product life as it can, But depending on the amount of selection pressure that is exerted, we're going to see potential for resistance to develop, but the odds are not high immediately.
Anthony Hanson:All right, we have two related questions. One is asking about the increasing popularity of no till, and the other is asking about the increasing prevalence of cover crops. And both are wondering how that affects both pests and changes in their control.
Ken Ostlie:Bruce, you wanna take a first stab at that one? Well, no till, what
Bruce Potter:no till does is it leaves more residue on the surface. It's probably keeping those temperatures a little more moderate. It's allowing probably a few more opportunities for insects to overwinter in the field. Cover crops are kind of a something that insects in Minnesota aren't very used to. And when we look at, particular issues, winter rye covers in corn, we know are attractive to to migrating true armyworms.
Bruce Potter:So that's something people really need to be be looking for if they if they're in that situation. Probably, a little more attractive to black cutworms coming in as well because there's additional weed growth early in the spring that's not taken out with tillage. The other thing that we can see happening with cover crops is and I'm a little concerned about it in in dry years is that we've got a perennial, species out there in these cornfields, and it's giving spider mites an opportunity to up winter right in the cornfield on that rye. If, they're if they're able to move to corn before that cover crop is is removed or if the cover crop is left in there too long before it's terminated, they've got an opportunity to move right to corn within the field instead of having to, move off the field edges. So I think those are some of the bigger, bigger issues with cover crops.
Bruce Potter:In a lot of cases, we just don't know. They're a little bit little bit unpredictable right now, but definitely, there's a potential for some some additional insect problems we're not used to seeing in corn related to cover crops.
Speaker 3:All right, we have another question from David Reynolds. Are SmartStack hybrids keeping up with pests? Says it seems a fair amount of producers are planting conventional hybrids.
Ken Ostlie:Well certainly the amount of conventional corn has increased over the last four or five years in response to the budget situations growers are facing, but that's kind of a separate issue from our smart stacks keeping up with pest issues. And I think on the BT above ground dimension, there's now been established resistance of a number of the caterpillar species to the proteins found in smart stacks. Fortunately for us, those are all migratory and tend to arrive later in the season, so they're not a big threat for corn producers in Minnesota, other than if we have late planted corn, for example. A little closer to home, western bean cutworm has developed resistance to one of the pry proteins found up here. And in the maritime provinces, European corn borer out there has developed resistance to some of the BT traits as well.
Ken Ostlie:So, you know, it's a changing environment out there. And whether we're talking rootworms or we're talking VT traits against caterpillars, we're seeing continued use and continued selection pressures leading to more cases of resistance.
Anthony Hanson:Blake Carlson asks, is it possible that chopping corn heads on combines have helped reduce European corn bore populations compared to what we saw back in the 1990s?
Bruce Potter:Well, certainly not helping them any. Even even, in the older literature, there's some documentation that that tillage can kinda help, reduce corn borer by getting those overwintering larvae in a in a bad, spot. But the thing to remember about European corn borer is that they're able to move between fields and there's certain stages of corn that they prefer. And what you do in one field maybe helps that field to a certain extent, but it's the surrounding fields that are an issue. If we're looking at overwintering populations, and where where these corn, example corn borer populations build up, It's in areas where they've used, haven't had the BT, aboveground traits, and it's kind of a widespread practice in the area and they've done it over a number of years and that's where we see those populations coming back.
Speaker 3:Thanks, Bruce. Anonymous asks, What percent of growers use planter insecticide treatments?
Ken Ostlie:That's a good question. I don't have any recent data on that. Bruce, what's your thinking?
Bruce Potter:Well, don't, I don't really know. It's more of it and I get, we get a lot of questions on it. Some guys are trying to stick with dry, some guys are switching to liquids. But, I think, I think as we've seen, BT traits fail, and there was quite a few of those last year, Ken, the interest goes up and we're seeing even some research results now where we're getting an economic benefit for adding a layer of insecticide over the stack. So I think that's gonna increase this year and we'll see what happens, with new traits and developments in corn hybrids down the road.
Ken Ostlie:Anthony, I'd like to add a little more to what Bruce was saying on the layering issue. I certainly agree with what Bruce said. The challenge in all of this is knowing kind of what level of resistance you're facing in your fields. And if you're relying on yield data to tip you or if you're relying purely on lodging, you're behind the game. By the time resistance issues become so noticeable there that you're starting to contemplate a soil insecticide or switch in BT traits, at that point, the field's already producing so many beetles.
Ken Ostlie:For example, the reportable criteria in EPA for reporting a field failure to a company is half a node with some of the pyramids right now. And at that point, you're already producing over 250,000 beetles per acre. And those are beetles with resistance traits that are spreading through the community. So they may be ending up in your, sowing, you know, other fields you have and sowing your neighbor's fields with higher levels of resistance. The insecticides won't change that.
Ken Ostlie:They're an independent mortality factor, and I'd say most of the time in our trials, only see about 60% reduction in populations with an insecticide. So the insecticides often by themselves are considered lodging insurance, rather than, you know, a kill approach to a population. You want the kill approach, rotate.
Bruce Potter:Yeah. Some of these fields again are to the point that they don't really have any choice anymore. So, but again, goes back to that earlier question on how do you know when you've got too much continuous corn and the only way to do is scout and look, in the case of root worms, look for beetles. In case of corn borer, things like corn borer or cutworms, do the scouting in season.
Anthony Hanson:We have another question from Bill Stangel. He asks, during state surveys, are conventional fields specifically targeted to look for European corn borer? And he also asks, whether northern corn rootworm has been able to overcome BT compared to western corn rootworm.
Bruce Potter:On the corn, are you talking about surveys for corn borer?
Speaker 3:It looks like it. Yeah. So
Bruce Potter:Yeah. And and we've done we've done that in the past, but but part of that survey to be maintain continuity, it's random fields as well. You might suspect that if you're gonna find a corn borer in that survey, it's gonna be in a non BT field. Ken, you wanna address the corn rootworm part?
Ken Ostlie:Sure, on corn rootworm, it's pretty common observation among ag professionals that are out looking at fields that we're seeing more Northern corn rootworms out there, and that kind of reinforces what they've been seeing over a longer period in Wisconsin. In terms of the fields that have been reported to us where sticky traps are being monitored, for example, there are definitely fields that appear to have elevated Northern corn rootworm levels, which is very remarkable considering it was only three years ago that I had ag professionals coming up, or four years ago, that I had ag professionals coming up to me and asking, where are the northern corn root worms? Because they were seeing hardly any out there. And so something has definitely changed in their favor. And you can have a discussion about whether that's a result of starting to see BT resistance developing in the population, and that's why we're seeing more of them.
Ken Ostlie:Or reducing competition from Westerns is another potential benefit of the colder winter we had like in 2013 and 'fourteen. Whatever the reason, there's definitely more Northerns out there, and we're seeing kind of a general uptick in populations of concern in terms of how many beet, corn rootworm beetles are out in fields.
Anthony Hanson:All right, we have another question from Ryan Hagedorn. He was asking, he uses capture and furrow in conventional corn, he also has a corn soybean rotation for all of his fields. Have you seen any issues coming up with capture or are there any other insecticide options we should be considering?
Ken Ostlie:I'll take a first stab at I know Bruce has some data that he might wish to share results from as well. But in our trials, when pressure builds, capture performance declines, and it's in some of the trial sites where we're deliberately going for high level subpopulation, we do see, you know, performance issues with some of the less effective liquids. In terms of other products right now, we're seeing good performance with Force EVO, and with two newer products, Index. Index, let me take a quick look here, Ampex. And I don't think Ampex is a full label yet.
Ken Ostlie:And I know that index is a fairly hot product, because it's an organophosphate erythroid blend. So there would be some handling, you know, precautions that growers would need to take. But there are some liquid options that are looking fairly good out there that would give capture a run for its money or exceed its performance. Bruce, what have you been seeing?
Bruce Potter:No, I think I agree with that, Ken. At Lamberton this year with some pretty horrific rootworm pressure, and I think it was partly due with when the rootworm egg hatch occurred versus corn planting and the summer weather, but none of the liquids looked very good this year. But even at that, they kind of followed that same order that you described with index and force EVO on top and then declining from there.
Ken Ostlie:Yeah, one of the other things, Todd, that I think everyone should consider is that when looking at performance and stability of that performance, the granular products tend to do the best. And then they overlap with the liquids, which are a little poor in performance, and then that liquid spectrum, like Bruce and I have been talking, you have captures is on the less effective end of the liquids. And then you move into the seed treatments. And the seed treatments are the first to fall apart, even if you've got a twelve fifty rate out there, and a 500 in most cases only offers minor suppression, and a two fifty really offers very little protection.
Speaker 3:All right, for another question, this is from Rusty. Can we use natural enemies to handle corn rootworm or other corn pests? Bruce,
Ken Ostlie:this is Kent, either
Speaker 3:you could pick one. Yeah,
Bruce Potter:on the corn rootworm side, I think that actually still is happening. In fact, when we before BT, when we had higher corn borer populations, we'd have, kind of a cyclic cyclical nature to the to the outbreak. So we have a few years, with low populations that build up and and and then decline again. And one of the reasons for that, is believed to be, natural enemies, Bavaria and and that sort of thing. When we do our fall sort of surveys for corn borer, we're also looking for, parasitism.
Bruce Potter:And that even with the lower corn borer populations that we have right now, that seems to be to still be working. So in the case of corn borer, you know, they're still at least somewhat effective at suppressing populations. And then Ken, you might wanna talk about nematodes in corn rootworm.
Ken Ostlie:Yeah, so on the corn rootworm front, the single most vulnerable point for rootworms is just egg hatch to establishment. And there's a tremendous amount of mortality that occurs through that phase. Over the years, there's been a lot of incidental work done with various pathogens, bovaria, for example, like Bruce mentioned. Noceva. Yeah.
Ken Ostlie:And there's also been work done with nematodes, and interesting a lot we enough, the nematodes could be extremely effective in inundated rates. If you put out a huge bunch of them, you got good control. The trouble is the application timing was as the corn was approaching tasseling. So it was kind of impractical. However, Elson Shields at New York has looked at a different species and the idea of an inoculative release, where you just put out enough to get them established in the population, and he's been able to show long term effectiveness using nematodes.
Ken Ostlie:So I think there's some potential there. Are you going to get companies investing in something where they may only sell a product once every four or five years? That's a totally different question.
Speaker 3:So there's a follow-up question that kind of is being led into here. Else also asked, do you get a chance to look at and research how well do you think biological treatments to control insects are going to be? So is there anything more in kind of that realm going on that you're seeking?
Ken Ostlie:So at least on the rootworm front, the challenge has always been that there's of variables that drive whether or not these natural enemies are gonna be effective. Is it too hot? Is it too cold? Is there enough rain to get things active and to maintain activity into the period and the life cycle when it needs to be there. And so you have trials demonstrating potential successes, and when other people would follow-up on it in different locations under different weather conditions, etcetera, it turned out to be not very universally effective.
Ken Ostlie:And so that's been the challenge. I think the nematode thing on the inoculate front is the thing I've seen lately that comes the closest. You've been hearing anything more on corn borer or some of the other leaps, Bruce?
Bruce Potter:No, not not really. There's no. It's I know there's some commercial Bavaria out there right now. I, you know, and and I mean, it does it does it does kill rowworms, but, you know, I don't I don't have any good data on how well that actually works in a field situation.
Ken Ostlie:I know there's been some research that's been going on using things that modify insect behavior that would be more likely to bring the insect in contact with the pathogen, for example. But I think that's still at relatively early stages of development. So I don't know of anything that's, you know, widely proposed or widely effective?
Bruce Potter:I think you hit on this, Ken, and that anytime you're using a biological, whether it's for insects or nematodes or even weeds to a certain extent. The big issue is that that biological organism has its own set of environmental conditions and needs a certain amount of host to be effective. So they don't overlap real well.
Ken Ostlie:And I know when I was doing research with European corn borer, you get the opposite thing where we would try to do work with artificial infestations, But if the natural population wasn't doing well, our artificial infestations wouldn't do well either. So there's some more macro environmental factors that are affecting performance of some of these things. And unfortunately for growers, they want to know they can rely on these products to perform when they really need it.
Speaker 3:Right, so this goes back to the corn rootworm world. Harmon Wilkes asks about extended diapause, kind what's of the general state we're seeing with that lately?
Ken Ostlie:Well, diapause is alive and well. We were sort of following its progression through the state. Think of it this way, you had an epicenter in Southwest Minnesota, and there was also one kind of in South Central Minnesota, and over time those areas spread, and so you got, to say a different way, ongoing selection pressure allowed the extended diapause phenomena to be observed to more locations. But as this kind of front was moving eastward, that's when BT rootworm traits came in. And suddenly we lost the ability to track how far those extended diapause traits had moved and were still moving.
Ken Ostlie:In Nebraska and in Iowa, they've in general detected more Northern corn rootworm populations moving South, and they don't know to what extent that might be related to extended diapause. So yes, extended diapause is out there. We've got some phenomenal cases where we have BT resistant rootworm, northern corn rootworms that show the same level of resistance in the second year. So even if you threw a corn soybean rotation on top of, you know, a resistant population, that corn year is still getting hit with the same level of resistance the corn population had.
Speaker 3:That was actually another question that came up again was based on how widespread is ET resistance in Northern cordworms?
Ken Ostlie:Well, I would like to get the help of anybody listening to kind of explore that further. We know of isolated populations that are now higher than they've been in many years. We know we've got extended diapause fields out there where we haven't seen extended diapause in a while. Think of it this way, extended diapause virtually disappeared for about ten to fifteen years as a phenomenon people were observing, and now it's back. So if anybody wants to share their insights, I'm sure Bruce and I would welcome any comments they have.
Ken Ostlie:And if you've got a particular site that might be fruitful for research, let us know.
Bruce Potter:You know, Ken, with respect to extended diapause and BT resistance and any type of, change in behavior or resistance to pesticide, really the the the it's hard to detect when populations are low. So it might it might extended diapause may be widespread and and has always been widespread. We just don't see it because the populations are low and the same with resistance. And I'm a little concerned as if we have another good year for, rootworm populations this year. You know, it's real it's real, possible that that resistance is a lot more widespread and predominant than we think it might be.
Ken Ostlie:It's a good point. I always used to use a iceberg analogy, and essentially the size of the ice berg, the size of the population is going to determine how much we see out there.
Speaker 3:I have one last question and that will wrap us up here. And it's basically, someone was asking when they registered insect pressure was horrible in 2020, what should I expect in 2021? That's a pretty open ended question for both of you there.
Bruce Potter:Well, I think Ken kind of hit on it. Some of these populations are issues we're going be able to track within a field from year to year like corn rootworm or in an area like corn borer. Some of the migrants, we have no idea. And and, you know, the interesting thing that I'm kinda tracking is that we had that re we had that cold snap that went all the way down to South Texas. And I'm kinda curious what that did to some of our insects that overwintered down there, like army worms, cutworms, even cereal aphids.
Bruce Potter:So that made a change to the dynamic. So I guess I wouldn't feel too heartbroken if a lot of them froze down there, but we'll see what happens.
Anthony Hanson:So you just heard from the question and answer session from our strategic farming, let's talk crops session, what's bugging your corn back in March 3. Both doctor Ken Ostlie and Bruce Potter got quite a few questions from the different growers and other folks who attended this webinar. We'll also have another bonus episode following this for soybean cyst nematode in about a week or so. In the meantime, I hope field work is going well for everyone that can get out in their fields right now. It's starting to warm up here in West Central Minnesota pretty well, so I know we're gonna be out in the field quite a bit here pretty soon.
Anthony Hanson:So again, feel free to take us along when you're out driving throughout the day and listen to us and other University of Minnesota podcasts. Thank you for listening to the University of Minnesota's IPM podcast for field crops.
