Field Crop Webinar Series - Weed Management Challenges that Lurk for 2020

February 24, 2020

MSU Extension field crops weed specialist Dr. Christy Sprague covers several options on how to best manage problem weeds, such as horseweed (marestail) and waterhemp, as next season approaches.  The 2019 field season is one that many of us would like to forget. High numbers of weed escapes and several unmanaged prevented plant acres will lead to greater weed management challenges as we head into the 2020 field season.

Video Transcript

- Today we're gonna talk about some of the weed challenges that we're gonna face as we move towards the 2020 season and mostly I'll probably focus the majority of our time on one particular weed species and that species is gonna be marestail or horseweed. And the main reason for this is as most of you have seen throughout the year with a lot of the delayed spring that we had, all the rainfall, we had a lot of prevent plant acres this summer. And the number one weed that seemed to make it through all those prevent plant acres was marestail. So there were a lot of fields that look like this as you drove around the state. And as you start thinking about where some of those fields were, here's just kind of a state map showing where a large number of acres of our prevent plant acreage was or fields and you can see with the darker colored counties, those are the ones that had more prevent plant acres, and you can see we had quite a few through the central part of Michigan up into the thumb and also in the southeast portion of Michigan. So we had a lot of fields that just weren't able to get much done with, whether it was trying to get a crop planted or even trying to do some weed control later in the season. So what was done on some of these prevent plant acres this last summer? Well there's a lot of things that growers tried. There was some mowing, others did some tillage. Also various herbicides were sprayed. We saw a lot of late applications of 240 and dicamba to help clean up some of these fields. And then there was a lot of fields where nothing was done. So whether people could get out there and actually do anything or just couldn't see the economics in trying to help manage some of those weeds. So here are a few pictures of what some of those fields look like at the end of the season. So obviously we had those fields where nothing happened but there were some guys that tried to do some tillage later in the season and you can see we have quite a bit of marestail escapes and thinking that many of these plants are gonna be producing seeds so that's gonna contribute to what we're gonna deal with next year. Again we had a lot of different herbicide applications that may have occurred when marestail was two to three feet tall, not getting adequate control. Here was a field that either had 240 or dicamba applied to it. And you can see that there's a lot of plants that are still standing and probably didn't die as well as are gonna produce seed for next year. So why is this important? Well when we think about marestail, we'll call it marestail or horseweed interchangeably, there's quite a bit of seed production that happens with this particular weed. We actually see that marestail can produce about 200,000 seeds per plant. Those seeds are very small. They contain what is called a pappus on the end of the seed and you can see here it's this feather-like structure. And basically what that does is it acts pretty much as a parachute and can help have the seed fly many places. So again we're looking at a weed that is wind-blown and can make it to various different spots throughout the country. In fact there's been a little bit of research that's looked at how far marestail can move and this is some work that was done back in 2006 out east. And basically what they did is they took a remote-controlled airplane and were able to catch horseweed to see it up in that planetary boundary layer and they actually found horseweed seed as high as .08 miles up into the air. And when you predict with wind speeds that can be up to 45 miles per hour, it suggests that some of that marestail seed could actually be dispersed over 310 miles in a single event. So as we think about all the acreage that had marestail escape since last year, a lot of those fields that didn't have anything done, there is gonna be a tremendous amount of seed that we're gonna have to deal with as we move into 2020. So this is just some pictures from last year. So you can just imagine that as we move into 2020, there's gonna be a lot more fields that look like this or even worse. So one of the things I wanted to get across is how much does marestail actually affect yield? And we're gonna look at some of our soybean trials and kind of look at how much marestail can actually reduce yield of soybeans. So you can see the picture here on the left and this is two applications of roundup. So again much of our marestail populations throughout the state are glyphosate resistant and you can see that here we have a very strongly glyphosate resistant population. And again many of our populations are also resistant to the ALS inhibitors. So things like Classic and FirstRate. So it really limits some of our weed control options. So again if we're not able to control marestail, this had two applications of glyphosate. And then comparing it to one of our effective treatments. So the big thing to get here is how much yield are we actually losing by not controlling this marestail? So the two applications of glyphosate where we've got healthy marestail, basically we yielded 24 bushels per acre where we had an effective treatment, we basically saw 42 bushels per acre. So almost a 50% reduction if we're not controlling marestail. So it does tell you how competitive this weed is and how important it is to make sure that we're controlling marestail as we move towards 2020. So what are some of the things we can do to manage horseweed or marestail as we move into 2020? And we're gonna focus a lot talking about soybeans but many of these similar strategies could be used in corn or some of the other crops. In many of the other crops we do have a little bit more flexibility as far as particularly in corn for ways to actually control this particular weed. So when we think about soybeans, a good majority of our soybean acres have been played into Roundup Ready soybeans. When we're trying to manage marestail, Roundup soybeans will not be an option. Again with the glyphosate resistance it is gonna be very difficult unless we look at some particular strategies to hopefully try to get it a little bit better under control to help manage it. So we're looking at if we're trying to manage it in maybe either Roundup Ready or non-GMO soybeans, we're really, it's really gonna focus on making sure we have an effective tillage pass before planting at maybe a couple of passes but basically what we need to be doing is digging up any of those plants that are, have emerged prior to planning, starting clean, and tillage is one way we can do that. The other thing that we need to do is have an effective residual herbicide. A lot of those pre-herbicides that we have out there can give us some help with managing marestail and we'll talk about what some of those options are. The other thing to think about with an effective tillage pass is what it also does is it helps bury seed. Marestail generally germinates from the soil surface so you can see here, here's a diagram depicting marestail seed in the soil seed bank. There was some work back in 2006 that pretty much showed that if you were able to bury seed, again it's very small, it doesn't have enough energy to basically emerge from that, that very depth. So you can see here in this particular diagram, you see that at this half centimeter depth, 0% of the marestail germinated. So again just getting some of that seed buried is gonna help reduce the populations that you're dealing with moving into the next year. Again most of the marestail that we have is gonna germinate from the upper surface and a lot of it is ready to germinate once it falls off the plant. Now if we're looking at no-till soybeans, we really need to be considering making sure that we have some sort of post-emergence herbicide option. So what options do we have? Well pretty much if we're gonna be trying to grow soybeans in a no-till situation or a reduced till situation, we need to have some post options and that really goes with looking at some of the new technologies. Whether it's Xtend soybeans or looking at different soybeans like LibertyLink GT27, LibertyLink or also the new Enlist E3 soybeans. And we'll spend a little bit of time talking about what some of those options are. So when we start thinking again about our management steps, we wanna make sure we control that emerged horseweed prior to planning, we talk about how tillage can be an important portion of that. But if we are growing no-till or reduced till, we need to have an effective burndown treatment. And when we look at an effective burndown treatment, here are some of the options that we have. So the first three could be used in any sort of soybean technology. So for example, 2,4-D ester at a pint plus glyphosate. Again that glyphosate's there to help control other weeds in it where something like 2,4-D ester would be specifically there to help manage the resistant horseweed or marestail. So for using 2,4-D ester remember we do need to wait a week or seven days prior to planning. Other options we have is sharpen at an ounce with glyphosate again to help pick up control of other weeds and we do need to use methylated seed oil if we're using sharpen to make sure we get the most effective burn-down activity. Other options we have are to use Liberty. Liberty can give us some control of methylated in the burndown situation. We tend to see a little bit better control later in the season from the standpoint of a little bit warmer conditions but again we've got a point of rate range that we can look at. So those three treatments can be effectively used whether we're planning Roundup Ready soybeans, Xtend soybeans, Enlist soybeans, LibertyLinks soybeans, so we've got all those options. We have some more specific options for burndown when we start looking at specific traits. So for example if we are looking at planting Xtend soybeans we do have the option of applying registered dicamba formulations whether it's XtendiMax, FeXapan or Engenia. The other options we have if we're going to use Enlist soybeans, we can use the new formulations of 2,4-D in this case Enlist One. And at that rate we can use up to a quart. So we're basically using twice as much as what we would be using of 2,4-D ester. So potentially giving us a little bit better control because of that higher use rate. There is also Enlist Duo which would combine that new 2,4-D choline salt with glyphosate. So let's look at some data. So we've done a lot of comparisons looking at some of these burn-down treatments and how well they effectively control marestail. So in this particular chart we're looking at, glyphosate as the green bar. We're looking at XtendiMax plus glyphosate in the red bar, 2,4-D ester again with glyphosate. Sharpen with glyphosate MSO and then Liberty. And you can see we do have effective control about 21 days after treatment with all those different burndown herbicides. However as we wait a little bit longer in the season we start to see some more separation. And we see that control with 2,4-D ester and Liberty are a little bit lower than what we see with the XtendiMax and Sharpen. And the main reason for that is the types of residual activity that you might get from some of these burndown herbicides. We tend to see newer emergence with the 2,4-D ester and also the Liberty because of the lack of residual control. The other thing we can do is if especially if we're having issues with control, with just one effective site of action is we can do some tape mixtures of some of these different products to help us get two effective sites of action and hopefully it may be a little bit more consistent control. So here's an option, something like 2,4-D ester plus sharpen. Again we need to have that methylated seed oil in there and the glyphosate would also help. Sharpen plus Liberty's also been very effective. And then we can look at some burndown activity with Liberty plus metribuzin and then we'll talk about some of the residual aspects that metribuzin could give us as well as looking at gramoxone as another option but we tend to see much better control if we can take mix gramoxone with that metribuzin. So pretty much again we wanna make sure we control that emerged horseweed, whether it's with tillage or an effective burndown herbicide. And then the next thing we need to have is a good soil-applied herbicide. These residual herbicides are extremely important. And the main reason for that is we tend to see very continuate emergence of horseweed, and here is just an example of some of the horseweed that we've seen as we look throughout the season, these are some of the emergence counts that we've had over the last three years looking at emergence from 2017 to 2018 and you can see that we have emergence pretty much every week of the growing season. And that growing season we tend to see some differences in when that peak emergence hits. And a lot of that is due to moisture. So if you look at our 2017 bars you see that our peak emergence was on July 5th. Peak emergence for 2018 was at second week of May. And peak emergence of 2019 was that fourth week of May. One of the interesting things and I like to show these pictures is if you look at the two pictures, you do see that on this August 16th, this is actually pictures that were taken from the same field, we see that we have marestail as basically flowered, gonna be setting that seed out fairly quickly. We have marestail that's at that two to three inch stage. And if you look really close you can see that we have marestail that has just emerged. So again that wide range of emergence that we have also makes it very difficult to control and that's why it's really important to make sure that we have some sort of residual herbicide out there. So here's just an example looking at a program, burndown program with a residual and without a residual. So we have Roundup plus 2,4-D, burndown was very effective initially, but again with that new emergence and lack of residual control we see a lot new emergence. We have a treatment where we've added metribuzin to get us some residual control and that definitely helps manage that marestail plant. So again what options do we have? So our pre-emergence herbicides for residual control. I did mention metribuzin, that is one of the ones that's probably our best option. Metribuzin generally we like to be in that six to eight ounce range. There's a lot of pre-mixes and we'll talk about what some of those are, and that will help with marestail control. So for example here is some of those different burndown treatments. The blue bars when we add metribuzin in this case, we used eight ounces, you can see that we have much better control with many of the treatments by adding that residual component and this is our, this would be on July 5th, so 56 days after treatment where that really helps. And then if we look at our 2018 data basically seeing the same thing. The other thing you will notice is we do have some residual control of sharpen. So again this is another one that can provide a little bit of residual control. But some of those tank mixes with metribuzin over time consistently might be better. The other options we have from a soil applied standpoint are the Group 14 herbicides. These are products like Valor or Authority-type products. So we're looking at two active ingredients, flumioxazin as well as sulfentrazone. So both of these products can give us some residual control of marestail. They are fairly good, may not be quite as good as metribuzin if you're looking at 'em by themselves, but again we do have some tank mixtures that we can use 'em in. The one thing I do wanna point out is if you're thinking about using either some of the Valor products or sulfentrazone, there are some restrictions on tank mixes with Sharpen because that is another Group 14 herbicide. If you're thinking of tank mixing those two, you need to wait 14 days prior to planning. So in many cases if people are using products that have either flumioxazin or sulfentrazone in there, we're looking at maybe a 2,4-D or a Liberty burndown or they might be looking at the new enlist burndown or dicamba depending on what soybean technologies they're looking at. The other thing to think about is there are a lot of combinations that will have both a group five like metribuzin and one of the Group 14s like the flumioxazin or sulfentrazone and I'll show you some of those treatments as we look at some of the different pre-mixes are out there. And from these combinations we're looking at two effective sites of action. And that can help us with control, residual control of marestail. So here are some of the premixes. And this is pretty much a chart looking at the rate of metribuzin and we're looking at the dry formulation of metribuzin and we're looking at some of the different premixes along the bottom and some of the recommended use rates and then the colored bars basically tell you what its tank mix component, what site of action. So for example the red bars in Canopy and Canopy Blend that basically means that metribuzin is tank mixed with an ALS inhibitor. And we can see the bluer bars, those are ones that are Group 14s. Those usually again are the things like flumioxazin or Valor or sulfentrazone and some of the Authority products. So when you look at some of these different premixes, ones that would have two effective sites of action on marestail, we're pretty much looking at things like Authority MTZ which would be a combination of sulfentrazone and metribuzin. Dimetric Charged which would be Valor and metribuzin. Fierce MTZ would also be Valor and metribuzin, also the addition of Zidua and then Trivence, so we're looking at Valor, metribuzin and then the addition of chlorimuron which would be the group to the red, the red portion of that bar. So what are some of the post options that we have for control of horseweed? So we have Xtend, the registered dicamba products and Xtend soybeans. We have glufosinates, Liberty, there's a lot of different glufosinates products out there now that can be used in the LibertyLink GT27 beans, the LibertyLink beans or also they Enlist E3 soybeans and also we can be looking at Enlist One or Enlist Duo so that those 2,4-D choline salts and the Enlist E3 soybeans, so that gives us some other additional options. Particularly when we're trying to help clean up some of the misses that we might have from a burndown with a residual program. So we're gonna talk a little bit first about the Xtend soybean system because of some of the off-target concerns that we have with dicamba, we've really tried to focus looking at some of those dicamba applications early in the Xtend system. So we've got two pictures here looking about at Roundup PowerMAX as a burndown and then comparing it to Roundup plus XtendiMax which would be a registered dicamba product plus a residual and looking at marestail control and so we're only looking at dicamba early in the burndown having a good residual out there like Authority MTZ. And then what we did is actually just followed it up with Roundup to maybe pick up some of the other weeds besides horseweed because we had very effective horseweed control with that treatment. And we tend to see that and we've been looking at this for about, over the last three or four years have seen some very good luck with the burndown with the good pre-emergence products and really not having to focus too much on including dicamba in that post application. This last year was a little bit of an exception, we might have seen a little bit lower control than what we've seen over the last couple of years but in general it's been fairly good. So here we have Roundup by itself, XtendiMax alone. Again metribuzin with the XtendiMax, Valor with the XtendiMax and so forth. And you can see overall we've had around 80 to 90% control and that's just focusing on having dicamba in the burndown with a good residual product. We also had good luck with Zidua PRO. And then the last two treatments that we have on this chart we're looking at coming back with XtendiMax. So again we've got some different options out there. Some of the little bit lower control is just some of the new marestail rosettes that are coming up, so really not yield affecting and probably not gonna cause a whole lot of seed production. And again this is at the end of the season. If you're thinking about using the Xtend soybeans, remember that there are several restrictions if you're gonna be applying dicamba in that. So keep that in mind. We have a lot of that information in our weed control guide that focus on some of the different recommendations that are out there as well as kind of reminding you of some of the things you need to consider if you're gonna be making those dicamba applications in Xtend beans. The other thing that we've looked at many times is wheat or marestail control in LibertyLink systems, whether it's just straight LibertyLink soybeans, the LL GT27 soybeans or also the Enlist soybeans. Here's marestail control at the time of a post-Liberty application. You can see where we have residuals in there where we've got much better control. Again metribuzin is a key component and in many of these situations in our Roundup burndown and then again with just a burndown we do see emergence later in the season so some of those things that don't have a lot of residual can be quite a bit lower. But when we come back and clean up with Liberty, we actually have very good results. So for example here is a picture of glyphosate alone and then again a good residual product and then being able to clean it up with something like Liberty. There are several different residuals we can use as mentioned before. Here is just an example of Authority MTZ. The key thing is that when we start looking at making sure that we have effective burndown, having a good residual, that gives us a lot of power for good control and then really being able to help clean up those soybeans with Liberty. And those have held through all the way through harvest. We've also looked at some different Enlist soybean systems. This is looking at a low rate of Enlist Duos, so this is the choline salt that would be about equivalent to a pint and a half of 2,4-D in the burndown compared to just glyphosate, these were all applied pre-emergence. You can see we have much better control where that 2,4-D is. We can go to a little bit of a higher rate to where we would be, to the hort rate of the 2,4-D choline salt. But we can see here we have some newer emergence. Again not a lot of residual activity from 2,4-D alone. That's where those residuals are helpful. Here's looking at some of those burndown products. The blue bars would be the products alone. We have three treatments of Enlist Duo all about the same. Sharpen plus Roundup, all about the same. So we didn't get quite the residual control that we would normally or that we have seen before with Sharpen. Again so that's why it's important to think about including some of these other herbicides like metribuzin. When we added metribuzin at the six ounce rate to the Enlist Duo, it did increase control. And again this is at the time of a post-herbicide application. We came back with different post applications just to see how effective these were. And if you look at these, we do see very good control when we can clean up and it gives us another option. So for example we've looked at Enlist Duo so that would be focusing on the 2,4-D component. We've looked at Liberty. We can tank mix the Enlist One with Liberty. So again 2,4-D plus Liberty. So you can see where a lot of times when we have that post option, we've got some different choices, particularly in the Enlist E3 soybean system. So again any of those would work or some of those combinations. So one other thing that we've done over the last couple of years is try to see how well cover crops can actually help in managing marestail. Over the last two years we've had some funding by Michigan Soybean Promotion Committee as well as Project Green and this is a project of one of my students John Chomsky. He's been looking at sero rye and winter wheat as a cover crop and then looking at some various herbicide treatment levels. So one of the things you can see here is we've got an overhead shot and we'll look at some of these. So we've got strips that would follow these soybean rows, so we have wheat at 120 pounds. Here is our bare ground, rye at 120 pounds, rye 60 pounds per acre and wheat at 60 pounds per acre. And what you can see here is where the bare ground strip is, you tend to see darker more marestail compared and then we have these burndown treatments. So glyphosate again, it's not gonna control it. So we're really trying to see what suppression we would get just from the cover crop. And we do see quite a bit of suppression. These would be applied about a week prior to planting. We also have some other strips where we look at including a residual metribuzin plus Valor or just looking at an effective burndown. And you can see which ones tend to look the best. Again those residuals really help. The other thing I just wanna focus on with this particular talk is these ones up at the top and these are planting green. So this is where we planted soybeans into either standing wheat or standing rye and then killed off the cover crop a week later with glyphosate, and one of the things that you can see here is we see a lot of green marestail in that strip where the bare ground is and then you see a lot of residual or residue I should say of some of those different covers. So we have the two that are highly, have a lot of residue would be our rye at 120 and rye at 60 pounds. So let's look and see what that did as far as suppressing marestail. So what we have here is we have harvested marestail biomass, and this would be about the time of a post-emergence herbicide treatment. And as we look at the early termination timing and the different cover crops and the different seating ranks what we saw is both at the high levels pf 120 pounds of wheat or 120 pounds of rye, in two out of the three site years we saw a reduction in horseweed biomass compared to the bear ground or no cover treatment. When we look at planting green, you can see we substantially reduced that marestail by a lot. So a lot lower levels out there. So it's helping suppress the marestail. In particular we had very good luck with the cereal rye and the 120-pound, the higher grade of winter wheat and we saw in two out of three years very good suppression there from the lower wheat rate. So again just showing that maybe some of these covers can help in suppressing marestail. They're not gonna completely control it but this might be an avenue where we're not relying totally on a herbicide to help manage our marestail issues. So here are some closeups. We have the no-cover, you can see how healthy that marestail looks. This is cereal rye at 120 pounds terminated a week prior to planning, and you can see we have a lot less biomass out there. Again it's not gonna completely control it but it'll help eliminate some of those plants that you're looking at. And then we have cereal rye terminated at the higher level, terminated a week after planning, and you can see a lot more suppression. And generally see much better control of marestail. So how did these things affect soybean harvest? So we also looked at that. When we looked at the early termination timing, again a week prior to harvest, we could see that we had actually better yields when we had our cover crops there compared to the bare ground so it did help suppress some of that early season of marestail. And we saw that in two, basically two of our five site years of this study and then over the five average over the five when we had a post-emergence application or excuse me over the three when we had a post-emergence application, we did see higher yields with the Planting Green. So we're still looking at this trying to come up with some good recommendations. Most of our cover crops were planted at the end of September through about the third week of October. So again we were able to get some biomass and planning usually occurred around the last week of May. So some of our key management strategies for horseweed that we're looking at, making sure that we're thinking about possibly planning some of the soybean technologies that provide us with post control options. Make sure that we control horseweed or marestail prior to planting. The residual herbicides are extremely important, metribuzin is a key component. Also Valor which is flumioxazin or Authority which is a sulfentrazone products or the sulfentrazone products can give us some good residual control. Some of our rotations can be tricky with some of these products. If you are in a sugar beet rotation, the one thing you would potentially think about is using Valor. Also consider planting cover crops for early season wheat suppression. And then think about controlling horseweed or marestail and some of those rotational crops. A lot of times after wheat harvest we do see some new emergence of marestail and it's really important to make sure that we get those under control. So knowing that this is gonna be an issue in 2020, we need to really be thinking about how we're gonna be managing marestail in the future. We do have a really nice fact sheet that really outlines some of the control strategies that I talked about today, in particular in looking at some of the different soybean technologies and potentially some of the different rates that we have for some of those residual products and just thinking about the steps for success. That fact sheet can be found on our website which is MSUWeeds.com. It is also in the back of the 2020 MSU Weed Control Guide on page 20 or 220. It is a three-page fact sheet. If you want the color copy, again just go to our website and you can print that off. The other things that as we start thinking about the next year, two other weeds I wanna mention that we need to be on the lookout for that could be potential problems as we move into 2020. We've really started to see the expansion of waterhemp throughout the state. So I think as we look till next year, I think this is one of the weeds that are just, it's just gonna be popping up in more fields. Even if you didn't have it last year, we are seeing it explode. So thinking about trying to set up management strategies that'll also help with patrol of this. The other weed I would warn producers about is Palmer amaranth. Both of these pigweed species are more difficult to control. And when we start thinking about management strategies, a lot of the management strategies that we use for marestail are also applicable to managing waterhemp and Palmer amaranth with a few minor adjustments. There might be a few more herbicides that we can use from a residual standpoint. A lot of the Group 15s like Dual, Warrant, Zidua that can give us some good control of these weed species. So we do have a fact sheet out there looking at Palmer amaranth and waterhemp management. Again, another way you can get that is on our website or in the back of the Weed Control Guide and we're really looking at ways to be successful in managing these different weeds and really thinking about some of the steps that we can do to help manage them. So in that particular one, we also have some recommendations on corn as well as some in alfalfa to help manage those weeds. So this is our website, msuweeds.com. We do have the 2020 Weed Control Guide posted on the website so you can get to that. We also have some information on some of our commercial comparison trials where we look at some of the economics and some of the different treatments. So all that information is on there. And again you can get those fact sheets so you can have some more information on step by step and how to manage marestail next year as well as looking at waterhemp and Palmer amaranth control. So with that, I think we have a few minutes for questions. I'll let Ricardo handle that. - MSU has done in-depth blocks on those hard weeds to control by adjusting water pH that your week X solution. You have done anything about that related to water pH? - So one of the things, there's a lot of pH adjusters and some of the different herbicides can affect or can affect water pH and then water pH can also affect the activity of some of those herbicides. Most of the stuff we've done is really looking at some of the conditioners to see if we can get better activity for things like glyphosate or potentially Glufosinate. With a lot of the resistance issues, changing that pH is not gonna do anything just based on how those weeds are resistant to those herbicides. So again, I think the key thing is to look at what herbicide you're wanting to use, looking and then also look at what are gonna be what we would say is our recommendations for some of those additives. - I have a question for (mumbles), he's asking if there are options for organic farmers trying to control horseweed without herbicides? - Yeah so with organic farmers it is tough. Again, the biggest thing that you have is your tillage equipment. And as I mentioned before, making sure that we're starting clean and then helping to bury some of that seed, blow that surface. And I know you're gonna be doing a lot of tillage, whether it's with a tide leader or rotary ho. A lot of that might kick up some of that seed. But again, I think you're gonna end up reducing a good majority of that by some of that early season tillage that you have that'll move it down a little bit further than probably what you're doing with some of the in-season tillage. But the key thing is to get 'em when they're small and then also making sure that we get good canopy closure. That's one of the things that would also help some of that shading. - You had MSU (mumbles) blocks on the typical to weeds but adjusting water pH down to a week at solution. And he put the parentheses, allowing herbicide mix to go to weeds is keen into mitigate alkaline hydrolysis, allowing the herbicide mix to go to a week critical and to mitigate alkaline hydrolysis. - So I would say that we really haven't done a whole lot with that, but I think one of the key things is when we start talking about these hard to control weeds, the nature in which they're resistant no matter how you got that herbicide in there, it's still not gonna be effective at controlling it. - All right. So and Tom is asking how it can sharpen or better be used on Roundup Ready soybeans or just expand beans? - So Sharpen and Valor both can be used on Roundup Ready soybeans. I would say though that the one thing I have mentioned is you cannot tank mix the two of them. Again you're looking at the burndown in residual. Both of those would need to be applied prior to planning soybeans. Again so many of those products that I talked about, those pres, they need to be on there whether it's Valor, any of those sulfentrazone products, metribuzin all need to be applied prior to the soybeans coming up so we're looking at a pre or part of the burndown application. Valor and Sharpen cannot be tank mixed together unless they're applied 14 days prior to planning. So many times if you're thinking about using Valor, you would wanna look at using something else like 2,4-D as the burndown or Liberty in a Roundup Ready system. You would have some more options if you're looking at some of the other strategies. Or you could just look at using tillage and then use the residual of Valor. - Yeah, so like I said it's just for (mumbles) applications right? - I'm sorry? - So Valor and Sharpen is only for spring and fall applications right? So yeah it's just prior to planter (mumbles). - Prior to planting yes. Not as the soybeans are up. - Clyde is asking you if it's time to bring the moldboard plow out of the wheels. - That's a good question. There's actually been a lot of work looking at trying to bury weeds, weed seeds. And a lot of it's actually been done looking at some of the waterhemp to Palmer amaranth, some of those amaranth species. And what that does is it helps and they're talking about a one-time moldboard plow to help bury it and then let those seats degrade 'cause generally over time those will degrade. But you wouldn't wanna go back and moldboard plow it the next year because at that point you're just bringin' those seeds back up to the surface. - We have another question that is, will crimping or flail mowing control marestail? - Okay, that's a really good question. So with crimping or flail mowing control marestail? So when you think about marestail, one of the things that we did actually later this season we were trying to look at some options to control marestail and some of those Prevent Plan acres. When you look at mowing, what ends up happening is you mow the top off, it looks pretty good, it looks kind of like a carpet. The next thing you do is you start to see it where it, the axillary buds branch out and then what you're really seeing is kind of that Christmas tree effect. So instead of the one stem that you have, you might have two or three or four. So in some cases, they might be producing more seen. So that's one of the key things. With the crimping, you're probably not gonna get any control because it's not gonna completely break that stem and it'll just pop back up and then produce seeds. So it'd be quite a bit different than what we see if we're looking at crimping cereal rye just as it's about ready to head out, or that would stay down, it doesn't work with marestail. - So Christie we have a question here. Actually, how can you make sure or maybe the question is how can we minimize the chance of resistance to happen which is a problem we have right now. Because we are going with a glyphosate so how can I make sure that they're not gonna lose Liberty or dicamba in the next two years? - Yeah, that's a really good question. I think the key thing is we always strive to incorporate other strategies right? So we talk about using different herbicide sites of action. So you didn't really hear me say I want you to go out there and apply Liberty twice. Or I want you to apply dicamba twice. Now you can do that, but again you're putting that selection pressure on there. So by including things like a good residual and we know that also give us some benefits because some of these other ones are not gonna give us any residual activity, particularly Liberty. We're using multiple herbicide sites of action. That's why with some of those burndown treatments I showed you where you could have two different sites of action and where we have two effective were much better than one, so we're not putting a lot of selection pressure on there and that's really one of the other reasons why we're looking at, can we incorporate cover crops into this system so we're not just relying on herbicides? So that's one other thing. While they're not gonna be totally effective by themselves, in combination with some of the herbicides, we're gonna be reducing some of that selection pressure on those herbicides if we can get some control with those cover crops. - Okay, thanks so much. Well Johnny is asking how well does the MSU guess what (mumbles) work? - The test bot combine? It works pretty well. Our test bot combine seems like it was almost as expensive as a full size one. So yeah we have very good equipment that we've been able to keep up with and it does a pretty good job. - Well and we have another question here and this a few people asked more questions, we have a few more minutes. Does half-killing the weed enhance herbicide resistance? - So that is a good question and there's a lot of thought in that. And a lot of it really depends on what the mechanism of resistance is. So if the mechanism was just what we would say is a site of action or a mutation of that particular site of action like what we see with ALS inhibitors, it's usually, it's, either it's resistant or it's not. We are seeing more cases where if you're not controlling the weed and depending on again some changes in how that weed is resistant, that actually could potentially contribute to that. So it's really important to be focusing on trying to manage the weeds that we have out there. And we've talked a lot in the past about thresholds and really right now with the resistance issues and stuff that we have, we kinda have basically zero tolerance for some of these weeds because of some of the issues that we have, in particular when we're talking about resistance and multiple resistant weeds. - Well thank you. I have one last question here from Dan. And Dan asks a really good question. He's asking if we have any problem with increase army worm a problems where you planted rye cover crop. - Yeah that is a really good question. In our trials we did not have any insect issues. In particular I know that when we go to things like trending new covers in going to corn, a lot of times we do see more issues with insects, particularly army worms and some of the other ones. So we've been monitoring that, and again we're kind of in our early stages on some of this but we do have a lot of specialists on campus that are looking at cover crops and from our research sites, particularly in soybeans we didn't have a lot of issues with insects causing problems but we have seen that in corn where we've had cereal rye or we've have tried to plant into strip of cereal rye with corn and some of those. So a lot of times we need to have that cover degraded prior. And the one thing I would say is that the more suppression you have is based on the amount of cover that you have. Again our cover is we're planted in a couple of years where we had cooler falls, so we didn't have a lot of growth in the fall. So primarily most of our growth occurred in the spring and we didn't have really huge biomass levels. And that's why we really saw the benefit of the Planting Green. - Awesome, thanks so much. Oh Chris, Christie just one last question. Do you think a farmer that is a (mumbles) farmer and he came up to you and said I don't wanna use tillage. So is he really behind the conventional farmer when it comes to control marestail? - I don't think so. I think if you're not using tillage, that's great because there's a lot of benefits to no-till. The one thing I would say is that if you're not gonna use tillage make sure you have a soybean trait that you're using, a trait package that you have some options for post-emergence activity. So for example, maybe something that has, where you can apply Liberty to right? So we still, we wanna have a good burndown and we wanna have good residual but we wanna be able to clean it up in crop. So that might be using glufosinate or Liberty and the LibertyLink, LLG GT27s or the Enlist soybeans. If we're using dicamba soybeans we have the option of dicamba post-emergence. Or if we're using the Enlist E3 soybeans we do have that option of those 240 formulations in list one or the combination with Enlist Duo in the Enlist E3 system.

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