A Comprehensive Review and Recommendations for Soybean Aphid Management in 2024 from Dr. Robert Koch, University of Minnesota Extension Entomologist
Good day and welcome to the University of Minnesota Extension Cropcast. I'm your host Dave Nicolai with University of Minnesota. I'm a crops educator, in Extension and my, co host today, doctor Seth Nave, is out of state actually at a conference in California. So I'm here with doctor Bob Cook and Bob is our extension entomologist here at the University of Minnesota. Bob's primary duties are involving the soybean crop across the state of Minnesota and the reason we asked you in Bob was to talk a little bit about a current subject that's on everybody's mind in soybean production in terms of insects, especially this year in the month of August at this point in time and that is soybean aphids.
Speaker 1:So welcome Bob.
Speaker 2:Thanks Dave. So this is
Speaker 1:a good opportunity, Bob, to review a little bit on soybean aphids before we get into the management and economics etcetera. Can you review for the audience a little bit in terms of the soybean aphids themselves as far as the biology? We've we've had them around for a number of years. They're not a problem typically every year but is there anything unique about this last year? We had a mild winter.
Speaker 1:Some people surmise that that might have an effect. I don't know if there's any way to really pinpoint what may be the actual economic and the environmental situations that are concurred that bring this problem to the forefront for Minnesota Soybean Producers.
Speaker 2:Yeah. I think, you know, after the last couple years where we did not have much for aphids and now we have so many aphids around it, I think it is good to review a little bit of the basics here. So again, the the soybean aphids are these small sap sucking insects that are, attacking soybean right now, and these insects spend the winter as eggs on buckthorn. So they're in the tree lines and wooded areas around our soybean fields, and, the winter temperatures are pretty mild. You know?
Speaker 2:So coming out of the winter, we were assuming we had pretty good survival, pretty good numbers of the soybean aphids making it through the winter. And then in the spring, their eggs will hatch and they'll go through a few generations on the buckthorn plants, and then eventually, they'll develop the winged generation that'll fly to soybean, and then once they get on soybean, they'll start reproducing there and their reproduction is asexual. So they don't need to mate and they're not laying eggs. They're giving live birth, so giving birth to their little baby aphids, and those baby aphids are actually born pregnant. So they're they're coming out already with babies inside of them, so they call it telescoping generations.
Speaker 2:And that's why these insects have such a high reproductive capacity. How their numbers can build up so fast because, you know, they're not wasting time. They're not waiting for eggs to hatch. They're not waiting to find mates. They're just reproducing right away.
Speaker 1:And early
Speaker 2:in the season, I was thinking maybe with all those heavy rains, we were gonna take a toll on the populations because when those aphids are colonizing soybean that's in the small vegetative stages, it doesn't provide much protection for those aphids. So I thought the heavy rains were gonna maybe knock their populations down, but that appears not to have happened. We've got plenty of aphids out there.
Speaker 1:Now we we talk about reproduction on a fast pace. There's a term that's oftentimes used in in talking about soybean aphids and that's referred to as doubling time. Can you talk a little bit about that?
Speaker 2:Yep. So I mean as the name implies that's simply just the time that it takes for the population of the soybean aphids to double. So if you went out and scouted your field and you had on average a 100 aphids per plant, the doubling time would be how long does it take for that population to get to 200 aphids per plant. And back in the early days of soybean aphid, the early 2000, Dave Rigg still here at the University of Minnesota prior to me, his group did some research under laboratory conditions and found that under under ideal conditions in a growth chamber with the same super comfortable temperature for the aphids all day long, night and day, they could double their populations in, you know, 2 days or less. But remember, that's ideal conditions all day long.
Speaker 2:No natural enemies there. No predators eating the aphids. No diseases. So those values don't necessarily translate to field conditions. Under kinda average field conditions, these doubling times have been estimated probably closer to, you know, 5 to 7 days.
Speaker 2:But, you know, we can get streaks in the summer where temperatures are much more favorable to the aphids, and maybe there aren't as many natural enemies in a field at a given time and these aphids can double. We have doubling times as short as, you know, maybe a few days.
Speaker 1:I think the weather records this past summer have indicated that we've had very few days in the nineties. Therefore, temperatures, a lot of them the seventies and the eighties and so on. So in that situation you're not surprised that, you know, we're gonna be building up and especially at this point in time of the year it seems like from early August to to late August is often a prime time.
Speaker 2:That's right. You know, that that laboratory research from David Rexdale that I mentioned, you know, that was showing that the aphids don't do not do well when the temperatures are in the, you know, the mid to upper nineties. That really slows down their their reproduction, their population growth. But like you said, you know, though those temperatures in the upper seventies, low to mid eighties, when we're feeling comfortable, that's when the aphids are comfortable and doing really well. That's when their populations can grow fast.
Speaker 1:Now there's some other environmental things that can affect their population. Do you want to talk a little bit about from a standpoint of maybe too much moisture or or there's disease? Yeah. What are some of these other factors that can interfere with their reproduction?
Speaker 2:Yeah. You know, I kind of mentioned it earlier. Right? So heavy rainfalls, you know, I think in the earlier vegetative stages, those can be more impact full on, you know, like knocking aphids off of plants, drowning aphids. But I think once our soybean plants get bigger, that canopy closes.
Speaker 2:I think the plants provide more protection where, you know, if you get a big storm, it it will probably reduce the population some, but but not as impactful as, you know, when we've got the small soybean plants. Another thing that the moisture can do and especially when we get, you know, streaks of, you know, cooler temperatures, higher humidity, and and these are kind of conditions that might favor some of the the plant pathogens. Though those same kinds of conditions can favor pathogens, diseases that attack the aphids. So there are some fungal diseases that can do a real good job in suppressing or knocking down aphid outbreaks if the weather conditions line up right. And in some of our research plots this year, where we're starting to see the aphid populations decreasing pretty fast, we're seeing some signs of, of some of these infestation by these fungal diseases.
Speaker 1:Now there there's a visual cue here too, isn't there? When you talk about seeing the signs, you can visually see the impact of some of these diseases. Is that true?
Speaker 2:Yeah. That's right. You know, so so these aphids that are killed off by the fungal diseases are they're kinda discolored, you know, almost, brownish to kinda reddish, almost kinda color, and they might look a little bit fuzzy as as the fungal, as a fungus is growing on them. But as you're out there looking at aphids, you might also see other things and there are tiny parasitic wasps that can attack the aphids, and when they kill the aphids they leave behind what we call aphid mummies. And those are essentially just the the aphid carcasses, but they take on kind of a characteristic appearance where one group of wasps will leave these, black mummies that are kind of the typical aphid size, but they're black and shiny rather than, you know, kind of the bright greenish yellow color of of a healthy aphid.
Speaker 2:And then there's another group of parasitic wasps that will make mummies that are kind of more plump, kind of rounded, and kind of a light tan color.
Speaker 1:So in terms of visually looking at these are some things that probably a good hand lens obviously would be would be helpful.
Speaker 2:Yeah. A
Speaker 1:pair of sharp eyes and in terms of that and, you know, situations with that. You mentioned the parasitic wasp, maybe a little divergence here. For a number of years and we've looked at control in terms of native wasps and so forth but also there was some looking at the standpoint of where some of these might have had an origin over in China and other places of bringing wasps into the United States and so forth and releasing. But I think there's been more success with some of the things that have occurred naturally. Is that true?
Speaker 2:Yeah. That that's right. So, doctor George Heimple in the entomology department, has done a lot of work leading up an effort to evaluate different species of parasitic wasps that attack the soybean aphid in Asia and then doing research under quarantine conditions where they can safely evaluate if these wasps are gonna potentially be effective against the pest, against the soybean aphid, and then at the same time, trying to document that these wasps are not gonna have unintended impacts on native species here. So they evaluated numerous different species of wasps and identified some that looked like they would be effective against the pest, against the soybean aphid, and would be unlikely to have these unintended bad consequences. But after doing some of the releases of, I think, 2 different species, unfortunately, it looks like those species did not establish here.
Speaker 2:I'm not sure if we know exactly why, but it might be an inability to survive the winters here. But while all that was going on, there's a different species of wasp that made its way over here on its own somehow from Asia, and it's called Aphelinus certus. And it's one that, this group of researchers evaluated early on and decided not to examine further because it does attack other aphid species, and they didn't want to be releasing something that that could could have these other environmental impacts attacking a bunch of different native species. So the this Aphelina assertus made its way here. It's, spread across the eastern US in soybean, and it's attacking soybean aphid.
Speaker 2:We see it pretty readily in soybean here and, you know, some people think it's, you know, definitely contributing to suppression of soybean aphid.
Speaker 1:In addition to the wasp, but there are other natural enemies that are out in the field. Are there some signs and some particular insects if they are on the increase to help you determine whether or not, you know, there's an, quote, aphid food source here?
Speaker 2:Yeah. So lady beetles or ladybugs are really important predators of soybean aphids, and early in the season, they can if you're walking through your soybean fields and you start seeing ladybugs or lady beetles on the plants, that's a pretty good into indication that you've got soybean aphids there. So they can be kind of a scouting tool early on for knowing if you have an infestation. But when you have, heavy infestations like you do this year, you know, in the fields that I've been looking at for some of our research, we're seeing tons of these lady beetles out there. Right?
Speaker 2:You know, so that they can research has shown that they can do a good job, you know, helping to prevent and suppress aphid infestations, but they're clearly not a silver bullet. Right? They're out there, but, you know, we still have, soybean fields reaching damaging levels,
Speaker 1:you know. We'll talk about damaging levels for just a second and keeping those beneficials in mind. How often are you recommending scouting in terms of situations that, you know, I suppose you have a scenario of where you haven't made any applications of insecticides, just the field itself. And versus, maybe talk a little bit about scouting after if you do make an application. How do they how do they compare?
Speaker 2:Yeah. I think, you know, regular scouting for soybean aphid, ideally, you know, every week, maybe up to every 10 days, something like that. We wanna be looking at the fields to, you know, have a feel for what that aphid population is doing and then using the economic threshold of 250 aphids per plant to make that decision on when to apply the insecticide. And we can maybe talk a little bit more about the the thresholds in a little bit, but getting back to the the idea of scouting, you know, we wanna base our decision to treat a field based on scouting. But after we treat a field or apply an insecticide, we wanna get back in that field, you know, after several days, you know, clearly after the the reentry interval, but give it some time for that insecticide to hopefully do its job.
Speaker 2:But we want to get back in there and not just assume that the insecticide did its job because we know we have resistance to some of the insecticides or that or that other things can happen with insecticide applications. So we wanna make sure that that we got the control we wanted out of the insecticide.
Speaker 1:And we talked about scouting weekly.
Speaker 2:Mhmm.
Speaker 1:So if you are are trying to get a baseline level of what's going on in particular field, is that still the the best recommendation that we could probably be is is to visit that field and and do do a thorough job not, you know, just from the edge of the field? Yeah.
Speaker 2:I think so. You know, we wanna we wanna get out into the field looking at plants spread throughout the field. And, you know, after treating the field, you know, that scouting is important not only in case there's a failure due to resistance or something else, but but fields can get recolonized. You know, we get into certain times of the year, you know, midsummer, later in the year when the aphids develop winged generations again, and they can leave certain soybean fields and recolonize others. So we've seen situations where fields get sprayed.
Speaker 2:You eliminate the aphids that are there, but you might also eliminate all the lady beetles and other predators. And then if you get more aphids or new aphids colonizing that field, those populations can grow very rapidly because there are are no predators or natural enemies there to keep their populations in check.
Speaker 1:Is there a recommended technique, you know, in terms of scouting methodology here? You want to cover the field whether it's an m or an x, whatever it might be, but are you gonna look in the upper part or the lower part, pull up an individual plant, count it, put it down and go to the next next stop and so forth? But, what's a good way to to help you in terms of ascertaining whether or not you are at at at a high level?
Speaker 2:Yeah. You know, so scouting for soybean aphid, it's pretty similar to the recommendations for a lot of different insect pests. Right? You wanna get good coverage of the field for your scouting, you know. So we might recommend, you know, walking in an m shape pattern in the field, and that's just to ensure you you get that coverage.
Speaker 2:You're getting into the field, not just making decision based on what's going on on the edge of the field. And then while you're walking that large m shape pattern through the field, you wanna take a look at soybean plants kinda scattered along that pattern. And for soybean aphid, you know, typically we're pulling plants out of the ground, and I like to start at the bottom of the plant and inspecting the stems and leaves. Working my way up the plant and kinda tallying up how many aphids I'm seeing on each of those plants and then, probably jotting down those numbers. And when you're done, averaging that up and seeing how that relates to that economic threshold.
Speaker 1:So let's dive in and talk about numbers here. Economic threshold numbers 250 per plant and on 80% of the plants in the field increasing. Mhmm. I think you also have to mention about the, you know, the the doubling time in there in terms of that but making a good observation across there. Is 250 an injury level or is this gonna give you time to get ready and do something?
Speaker 2:Yeah. So the whole thing with this threshold of 250 aphids per plant, that that's not the point at which the aphids are causing yield loss, not even not causing measurable yield loss, let alone, you know, not even economic yield loss. That's just that trigger point where once that aphid population gets to 250 aphids per plant, there's a pretty high probability at that point that they're they're gonna continue to increase to more damaging levels of probably, you know, closer to 700 aphids per plant where the amount of yield loss caused by the aphid infestation at that point is likely to warrant an insecticide application.
Speaker 1:We refer to that as the injury level as opposed to
Speaker 2:the economic injury level. Uh-huh.
Speaker 1:In in in terms of that too?
Speaker 2:And and then based on those kind of average aphid population growth rates are doubling times that we talked about before. You know, it went from that time of hitting 250 aphids per plant to that economic injury level of closer to 700 aphids per plant, I think it was 680 based on some of the calculations. You know, that would typically give you 5 to 7 days to line up that insecticide application to knock down the the infestation so it doesn't continue increasing to that that damaging level. However, you know, if you've got those real conducive temperatures for aphid population growth, maybe not many natural enemies out there, that window of time might be a little bit narrower because those populations could be increasing faster and could reach that, economic injury level, in in maybe just a few days.
Speaker 1:So don't assume that you have that that cushion level of 7 days all of the time. It's a lot of things could factor into that and make that much shorter than it would be otherwise. So you have to be really looking at that field on a regular basis with that. So and I imagine the same thing is going to be true even if you do choose to make an application of an insecticide, say for example, you know, one of the things obviously can affect the beneficials, it can affect, you know, the population of of the aphids. Do we talk about going back and rechecking and seeing what activity is is it still in the field?
Speaker 2:Yeah. We touched on this a little bit, Dave. Right? You know, would after the spray, getting in there to make sure you got the control you're expecting to get from the insecticide. Again, we we can't just trust that all these insecticides are gonna do their job anymore.
Speaker 2:We we've got resistance to the pyrethroid insecticides. You know, there there's there's chances that these aphids could be developing resistance to other insecticides. So if if that insecticide did not work, we wanna make sure we catch that. And then if we need to treat a field again, go in with a product from a different insecticide group. Right?
Speaker 2:Like, if you were to spray an insecticide from a certain group, you don't want to respray with that same group because that's going to create a lot of pressure for the development of insecticide resistance. We talk about alternating the insecticide groups. And then the other thing, like we mentioned, you know, a little bit ago is is, you know, this idea of recolonization. If if you're in a time of the year where you got a lot of the winged aphids moving around, you might, you know, do a good job controlling your infestation, but that field could get recolonized by aphids. And this is, I think, is especially important for the people who are doing some of the early treatments of fields, maybe when they're mixing an insecticide in with, you know, a herbicide or something like that.
Speaker 2:You know, we don't recommend doing that, but but folks still do it. And and when you do that, you might kill off those low numbers of aphids that are out there early in the year. But, again, you're also probably killing off the lady beetles and other beneficial insects that are out there. So then when aphid population start building up elsewhere and you get the winged aphids formed, if they find that field, it's gonna be a very, favorable location for their populations to develop because they don't have the natural enemies there.
Speaker 1:Well there's a lot of things that can vary. I mean your neighbor could have a different soybean variety planted at a different time. We're here in mid to late August. We talk about our soybeans getting into what we call the R5 stage which is the beginning. Training the next stage will be R6 when will be a full seed.
Speaker 1:You know, we have certain things that are going to impact in terms of how long those aphids are going to be economically, you know, infesting a particular field. At some point, you know, when they're going to leave and obviously in late fall and or sometime in September say for example go back to buckthorn or whatever it might be for overwintering. But in a lot of these cases it's a matter of timing. Just don't assume, don't pull the trigger based on activity of the neighbor in terms of that every field can be different, planting can be different, stages can be different, you know, etcetera to really go through that.
Speaker 2:Yeah and that's really important this year Dave. I think again with all the variability and planting dates out there. Right? You know, we've we've got, you know, fields that were planted late because of all the moisture and, you know, at this time of year those are probably going to be more attractive to the aphids and So
Speaker 1:we're talking about the younger soybeans. You know, the ones in comparison to an older field if they moved over, you know, that would be greener so to speak. You know, at a probably maybe an R3 to R4 stage yet at this point in time.
Speaker 2:That's right and I think because of some of that right now we're seeing kind of a mixed bag out there for population dynamics of soybean aphids. We're seeing some fields where the populations are already starting to decrease. You know, I've I've got fields where we had, you know, a 1000 aphids per plant in some of the research plots. You know, that was, you know, maybe 2 weeks ago and, you know, now they're already decreasing. But there are other fields, you know, that I've been seeing and hearing about where populations are lower but still steadily increasing.
Speaker 2:So you you exactly what you said, David. You can't just assume
Speaker 1:Right.
Speaker 2:What's going on in one field because of what's happening in other fields nearby.
Speaker 1:Yeah. And and they can be in more impactful in certain things and leave a field for whatever reason. And sometimes it's hard for us to really determine that that impact on full seed. You know, the economic thresholds, it's a little harder to make everything mathematically work out because we don't know exactly how long they'll be in that situation in in there but in terms of scouting. Let's talk a little bit about options for treating.
Speaker 1:If that's your choice, if you're taking the beneficials into consideration in high numbers, there's a lot of things out there on the marketplace. There's single modes of actions. There are things that are mixtures. We had older chemistry, what I call the pyrethroids and then if you go back even a generation before that, we had chlorpyrifos which has been in and out of the marketplace from a regulatory standpoint. But you know, I think in most cases, people are having to make their choices not so much on clopryophos anymore at this point in time, but maybe more on, you know, single modes of actions, mixtures, pyrethroids.
Speaker 1:Can you help sort that out a little bit?
Speaker 2:Yeah. So if you think about all the different products that are out there and available for soybean aphid, it sure seems like a lot. Right? But if you step back and think about those in terms of the insecticide groups that are available, we're really kind of limited. We we don't have all that much.
Speaker 2:You know, we've mainly got, like you said, the organophosphates that have, you know, products like chlorpyrifos. We've got the pyrethroids, and then there's, the neonicotinoids and then a couple other products that are kind of in that same insecticide group. And then there's, you know, the group 9, which is, a newer product as well called Sefina. So just kind of thinking through this list now, you mentioned chlorpyrifos. You know, so think back to the product like lorzban, and it's been kind of a regulatory roller coaster for chlorpyrifos.
Speaker 2:Right? Where it was taken away, then we got it back, and then now it's kinda kinda temporary availability. So currently, I think we've got 10 products that can be used for, soybean, chlorpura phosph containing products that can be used in in soybean this year. That situation is very likely to change for next year. So make sure you pay attention to information coming out from the Minnesota Department of Agriculture there.
Speaker 2:But, with the outbreak of soybean aphid this year, I think a lot of, farmers and agricultural professionals were relieved to have access to clopirofos containing products. I know quite a few people that have been using them, and and they still seem to be providing very good control of soybean aphid infestations. The pyrethroid insecticides, they were very commonly used and an important part of soybean aphid management, but that's that group to which we've documented soybean aphid resistance over, you know, a number of years now and across a broad geography across much of Minnesota and into some of the neighboring states as well. And I've heard reports of, people this year. You know, some people have tried using pyrethroid insecticides, and, they've gotten lucky where they've happened to have susceptible aphids in their fields, and those pyrethroids worked fine.
Speaker 2:But other people have had problems where they've decided to use a pyrethroid, and it's has not worked. So, you know, I do not recommend using the products with just a single pyrethroid, and that's solely based on the fact that we know there are pyrethroid resistant aphids out there, and and we can't tell right now which fields have them and which fields don't. So to me, it it's too big of a gamble. So then going beyond that, you know, we've got some of the newer products like Transform and Sivanto that are, in that same group with the, neonicotinoids or separate subgroups within that. And, and then there's the group 9 insecticide, saphena.
Speaker 2:And that acts a little bit different than than some of these other insecticides. And the main thing to remember with safina is that it it's, kills the aphids more slowly than some of the other insecticides. It'll stop them from feeding very quickly. So the aphids will stop feeding, but they're gonna kinda linger on those plants for a little while. Basically waiting to die from starvation or desiccation, maybe falling off the plants.
Speaker 2:One of my students who was doing some research on these called them like little zombie aphids that were on the plants after treatment. But what you gotta keep in mind is that these aphids that have been treated with safina, they're not feeding anymore. And an aphid that's not feeding is as good as a dead aphid. So we've got some, a fair number of options available now because of some of these newer insecticides. And then you mentioned mixtures, Dave, and that's where it gets pretty complicated, I think.
Speaker 2:And I don't know how close of attention people are paying when when we start using these different mixtures. You know, you get situations where you can have a product with a mixture of, you know, maybe 2 different pyrethroids. And, you know, I guess I would encourage people to think about that. You know, what are you gaining by having those 2 different pyrethroids in there when the aphids might already have resistance to the pyrethroids? There's, mixtures with, pyrethroids and neonicotinoids and, pyrethroids with, like the Saphina or the Transforms.
Speaker 2:Some of these newer more aphid specific chemicals are even being mixed with, with pyrethroids now. And, you know, the other day, Dave, you and I were talking about some of this and, you know, to me it I'm not sure how good of a fit that really is for Minnesota soybean pest management because soybean aphids are the main pest of concern in in Minnesota soybean, and we know we've got some of these products, Saphina and Transform, that do a good job on aphids. So I personally don't really see the value in adding the broad spectrum pyrethroids to that for aphid management. And I think it's kind of 2 fold. 1st, you know, we're not really gonna gain much in aphid control by having the pyrethroid there because the saphena alone or the transform alone will do a pretty good job controlling those aphids.
Speaker 2:And, you know, now you're by making that mixture, you're suddenly going from a product that will do a good job killing aphids, but leaving the natural enemies alive to having a product that's gonna again act like a broad spectrum insecticide because that pyrethroids is mixed in there, you know. So not only will it kill the aphids, it'll now kill the the natural enemies.
Speaker 1:That and that was my point is the benefits of some of these single mode of action might be better if you're concerned about the beneficials in not clouding the landscape so to speak with a with a mixture where you can't really maybe protect them as well in in terms of that because that's, you know, it's one of the selling points of some of these are the fact that they were, quote, easier, kinder on that beneficial population.
Speaker 2:That that's right. When it when it's just that one mode of action that's that's aphid specific. Some of the you know, one I think one of the main benefits of these mixtures would be if you've got a field that's infested with multiple pests. Mhmm. Right?
Speaker 2:You know, I I think that's where you can get the benefits from that. There is some possibility for, you know, utilizing mixtures in resistance management, but that gets pretty nuanced and it's kind of a a fine line to walk, I think. And in the situation with a lot of these mixtures that we've been talking about, it it's a pyrethroid that's mixed in with something. And again, we know a lot of our soybean aphids have resistance to the pyrethroids. So I that that's just one more reason why they don't make a whole lot of sense to me, because you're kind of going in, I like to say, half broken with with these, mixtures because the aphids already might have resistance to that pyrethroids.
Speaker 2:You're not gonna be getting as much control from that. And then, you know, are we, creating a situation where we might be selecting for more resistance that way.
Speaker 1:Okay. Well we're closing in on the end of our time here. Bob, any last thoughts that you have in terms of overall soybean aphid management looking in the future here in terms of that? What are some things that, you know, you can do if if you are aren't in a position or choose not to use obviously a insecticide product? Any other comments or just anything in general?
Speaker 2:Yeah. I think just kind of getting back to the scouting and and treatment decisions, you know, for this year. Typically, we recommend that threshold of 250 if it's per plant through the r five growth stage. Once we get into the r six growth stage, you know, especially kind of early r six. That's full seed.
Speaker 2:Yep. There there has been documentation of some yield loss there, but but we feel that it takes a lot more aphids to cause that yield loss. We don't have a, you know, a research based threshold for that growth stage yet, but if if you got a very large infestation in in that early r six, sometimes it probably makes sense or would make sense to, to spray those. But if if you're scouting the field regularly and using the threshold of 258 per plant, hopefully, you'll be able to prevent yourself from getting into a situation where you've got a large infestation in r 6, and and it gets a lot a lot more complicated to make those decisions at that point. You know, other than that, Dave, you know, after after all these years of, you know, researchers and, farmers and everyone dealing with soybean aphid, kinda sadly, you know, our management really still relies largely on insecticides.
Speaker 2:You know, we've got a lot of research that shows that aphid resistant soybean varieties with the RAG genes.
Speaker 1:Mhmm. You know,
Speaker 2:there's research showing that those can be very effective and especially if you've got multiple RAG genes in, individual soybean lines, but those are not widely available right now. I think in Minnesota, it's kind of mainly for the the organic niche market for those rag contain or, the soybean lines with the rag genes. That rag stands for resistance to aphids glycines, the the scientific name of the soybean aphid. You know, so hopefully, over time, those will become more widely available so we can get more toward true integrated pest management, where we're integrating multiple management tactics. You know, insecticides are probably gonna remain one of the tools, but if we can integrate, you know, pest resistant varieties and other things, you know, we've we talked about biological control, which is, you know, the use of these natural enemies.
Speaker 2:You know, so thinking about how we're managing the fields to, you know, make sure we can let those insects,
Speaker 1:help us out when they can. Dumb. Well very good. Now if folks want to read a little bit more about this, the University of Minnesota Extension we put out is called Minnesota Crop News and there was an article recently, I think on 13th August that came out, on considerations for soybean aphid management and Bob you were one of the authors on there so folks can can go on and search for that, Considerations for Soybean Aphid Management University Minnesota Crop News and it's very comprehensive and will give you a good opportunity for that. So we'd like to thank Bob, Doctor.
Speaker 1:Cook, for stopping in here to the studio, visiting with us here on University of Minnesota Cropcast. We appreciate your time, Bob. Thank you very much and we will look forward to finding out a little bit more about research and so forth as we go forward here with the number with the continuing episodes of Minnesota Cropcast. I've been your host, University of Minnesota Extension Educator in Field Crops, Dave Nicolai and we'll look forward to visiting with you next time. Thank you very much for tuning in.
