Weeds AR Wild Episode 12 Norsworthy/Ellis 5-18-21
Jason: I’d like to welcome you to the Weeds AR Wild podcast series as a part of the Arkansas Row Crops Radio. My name is Jason Norsworthy and I’m a weed scientist with the University of Arkansas System Division of Agriculture. Today I’m excited to be joined by Dr. Drew Ellis with Corteva and I’ve invited Drew to be part of this podcast because today we’re going to talk about the use of Loyant coated on urea in rice. Drew, I really appreciate you being with us today.
Drew: Thank you very much Jason. Glad to be here. Glad to be a part of this podcast and provide any information to be helpful to anybody listening.
Jason: Drew, last year you know I did a good bit of work with Loyant impregnated or coated onto urea and just looking back here this morning I think my program had somewhere around twelve to thirteen trials and I was really excited about some of the performance. We learned a lot last year as to what the product would and would not do and that is really going to be the focus of what we’re going to talk about today. But before I start with that, it’s my understanding that Corteva has obtained a 2EE label for the use of Loyant impregnated on urea in Arkansas and if you would tell us a little bit about that label and how it came about and really what that label involves.
Drew: Of course, so about two years ago, folks down in south Louisiana, pretty large water seeded market down there and they’ve had a history of coating fertilizer with herbicides and it’s not uncommon I guess, the application method, of herbicides to be used on fertilizer in rice. They really took that upon themselves to test use of Loyant in water and water seeded acres for control of specifically aquatic broadleaf weeds. Had some really good success, limited amount of commercialized applications and really bring it to our attention of the benefits that they see of it. So we continued some testing in 2019 and 2020, and also continue testing this year but really saw some good efficacy and good results. There are certainly some benefits to it, to the applicator, to the grower and the supplemental label now in most all mid-south states and for use in water.
Jason: Drew, when I think about Loyant impregnated on urea, and again just getting back to our plot work, what I saw in my trials last year was that it’s a very effective option or it was for us on weeds like rice flatsedge, smallflower umbrella sedge, our aquatic weeds, ducksalad, arrowhead, we saw good activity on goose weed, hemp sesbania, northern jointvetch or indigo. The one thing that we did also note is that when you’re looking at an impregnated application, it’s really important to a weed scientist, probably more important there than it is even with a spray application. I’ve been a big fan of the use of Loyant on hemp sesbania, northern jointvetch, even some larger plants but what we saw on our plot work last year is if you’re going to get effective control of these weeds, they really need to be small, and I’d say size is probably more important again with an impregnated application than with a foliar application, but when you think of these weeds, and I just gave you the ones that I consider to be effectively controlled, what do you think really are the strengths or weeds that a grower should target if they’re looking at using Loyant coated on urea?
Drew: Absolutely, the key weeds you mentioned are some of the targeted ones. I’d also mention eclipta, alligatorweed, there are good spots of alligatorweed in Arkansas. We do have additional herbicides that can be mixed in with our ducksalad kind of acres or some others that I would bring, the flatsedge, the rice flatsedge and ALS resistant, one I continue hearing to be trouble or problematic for the growers in Arkansas, I really believe there’s a good opportunity for it, that particular sedge we don’t want to focus only on the broadleaf aquatics here because that sedge, flat sedge is primarily ALS resistant, is a major concern and it has really good activity there. So those are some of the major ones that I come across.
Jason: You know as we, I think about Loyant coated on urea, and there’s other out there that farmers out there, growers that are aware of the fact that we’ve done research. One question I commonly get Drew is, well is this just purely related to flooded rice culture or with our row rice acres increasing is there any utility in this in a row rice system? The number one weed that we have in row rice outside of barnyard grass by far is Palmer amaranth and I’ve been very impressed with the use of Loyant for controlling Palmer amaranth in row rice. But when we take a look at an impregnated application of Loyant, you’re really not getting the coverage necessary for a control of a weed like that. You don’t have the flood to benefit you and just my experience has been, it’s not going to be a good option for controlling emerged weeds in row rice. Would you have a tendency to agree with that? 
Drew: Absolutely Jason, I think you hit it spot on with we’re utilizing that water, that flood, as a medium to disperse that herbicide into that column. Use of the coated herbicide in that row rice situation will be difficult to get coverage. Interjecting the size of the weeds and on our label we have reasonable size weeds, four inches for most of them, but the key thing is seventy percent under this label must be below the water, seventy percent of the weed should be submerged, so in that row rice situation you could see the difficulties we’ve had. 
Jason: Oh absolutely. Another question that I commonly get from folks is, what can they expect in terms of barnyard grass control with impregnated Loyant and again while we’ve had some successes and we’ve had some failures, I’ll be first, we’ve talked about that on this podcast before with Loyant, some of the resistant issues, even on a susceptible population, one thing you noticed a few moments ago is that I did not include barnyard grass as being effectively controlled. While we can get some populations with the spray, I really don’t think that we’re going to get an acceptable level of control of not only barnyard grass, I would say any grass with the impregnated Loyant applications so I think understanding really what you can and cannot do with a herbicide is a key to an individual actually having success. 
Drew: Absolutely. This focus of this supplemental label and this use and the successes that we’ve seen with it so far in Arkansas and tested. Commercial tests last year, we’re going to continue this year, have really been focused not on grass but really on a broadleaf weed and we really do recommend a program approach when it comes to handling some of these weeds like barnyardgrass, some that may be susceptible in foliar applications of Loyant. But I would recommend always to focus on a program approach for those particular weeds, as well as some of the sedge weeds we have, really they can be so thick and heavy without a program approach trying to rely on Loyant, one application in water like this will not be enough. 
Jason: I agree with you Drew. I think that’s a very good point. One thing that we within the Division of Agriculture preach time and time again is a programs approach to weed control and really trying to overlay residuals and really minimizing the need for these post emergence control options. Really that’s what this is. I mean Loyant, even though it’s impregnated on ureas, it’s really trying to look at post emergence control of these weeds. Another thing is when I think about Loyant, we’re really aware of some of the issues that we’ve encountered within the state. And I think one reason it’s got me excited about looking at Loyant coated on urea is that we’ve had some difficulties in terms of spraying Loyant and at times we’ve had some off target movement issues that we’ve had to contend with within the state and one thing that I saw in my plots last year is that when we went out and looked at a spray application of a low rate of the herbicide onto soybean, we looked at a one/fortieth x rate and we saw upwards of about eighty percent damaged from that foliar spray on the soybean but when we put it on the prill and we applied that prill at a one/fortieth x rate, one percent or less injury to soybean and that really gets me excited because again you’re not getting the coverage on that bean. Another thing is when you start thinking about a prill that distance of that prill is going to move off target during that fertilizer application is much much less than we get with a spray application. We haven’t conducted any research I’d say to directly quantify that other than the fact that Dr. Butts and my group did some work last year and we did look at a plane application, a foliar application with an airplane and we quantified the distance moved. We looked at a ground application and yes a ground application of a foliar spray moved considerably less than that of the airplane so the thing is with all pesticides you know as you start putting them in the air and you start getting that plane up, and that plane is a greater distance from the target, you’re going to have movement and that’s just something that we have to contend with. I really think the beauty of this Loyant impregnated coated on urea is we have less distance that it’s going to move and secondly you’re not going to get the coverage on the bean. But really what’s you’re getting is that prill solubilizes in soil, you can get a little bit of activity but again it’s relatively minimal. The other thing I’ll just point out in our research that we saw last year, regardless of the off target rate that we looked at and I think we looked at up to a one fifth x rate of Loyant or which would be one fifth x rate of urea impregnated, that Loyant impregnated on that urea, we saw absolutely no yield loss on soybeans, so that was really exciting because again that’s not what we see when we have some foliar spray. So I kind of saw that as a benefit. Any other benefits that you see in terms of Loyant being coated on urea Dr. Ellis?
Drew: Certainly the one that stands out probably to most growers would be the benefit of tackling two rice management considerations of fertility and herbicides at the same pass of the airplane so you’re not having to spray something and fertilize something with two different passes of the airplane. That certainly is going to help streamline and make the production more efficient. I think you’re going to be able to time things better by putting them together vs having to wait another day, but certainly some considerations around this that one would need to be cautious of, one being the fertilizer plant and customer buying the fertilizer, the applicator, make sure they have a premium grade fertilizer, urea or AMS. What we’re trying to do is reduce the amount of dust and standard grade fertilizer, so an SGN number, the soluble prill size number, let’s just say of less than two hundred, that’d be a standard grade according to the fertilizer industry and that would have potential for more dust and off target movement concern there, as well as when they’re impregnating it to utilize a nozzle system and stage that application of Loyant concentrate, either that fertilizer or stage process and we recommend about a hundred and fifty pounds or greater per acre, sixteen ounces of Loyant, that ensures a good drying of that without the use of a drying agent. So just so couple of little key benefits there or cautions to applicators to fertilizer plants when they’re impregnating.
Jason: Yeah and I thing, again, what this does is I think there’s some individuals that’s been reluctant to spray, make a foliar spray, at least by air of Loyant and it really opens up some opportunities to get back on some acres and I think utilize this product where it has a fit at least in these weeds that we’ve mentioned here. One thing that’s for certain, rice flat sedge, small flower umbrella sedge, I mean these annual sedges seem to be extremely, extremely problematic for us. Based on recent survey that we did I guess last year of the sedges in general are going to rank within the top five of weeds that we’re having to address, and as you said because of all this ALS resistance, this really opens the door for us of getting the product back in the airplane and trying to control these weeds. Another thing that I kind of seen is that the risk for injury that we get, we’ve had some injury from some foliar applications. I’ve talked in the past about some sensitive hybrids. What we’ve seen at least in our plot work is the tendency to get damage or have damage on a hybrid or even on some of these sensitive inbred medium grain cultivars is much, much less with the urea, the Loyant coated on the urea vs a foliar applications, so I’m really excited again that maybe we can take some of that out of the equation that we’re having to deal with. But one question that I get here Drew is, when I start talking about applying Loyant coated on urea, is what do we do to just ensure from a cleanout standpoint, what’s Corteva recommending and how can we be positive that we’re not going to have any residues in that airplane that’s going to result in damage to a subsequent crop? 
Drew: Absolutely, that at all part of the reduced potential for off target movement or impact to a sensitive crop that nobody wants to see, the applicator, the salesman, fertilizer, the chemical, to Corteva, to anyone, don’t want to see a detriment to a sensitive crop. And what we’ve found per testing, lab and commercial testing in commercial size applications that the aerial applicator needs to do a standard triple   rinse of the plane like you would with any other herbicide, ok, or any other application or herbicide involved. Triple rinse system, it’s two batches with the fertilizer, tender truck of fertilizer, non-treated fertilizer, once they get finished with the coated Loyant applications, take those two batches and run those through onto rice, not onto another crop, run them on rice, rice is very tolerant and then they can continue then using fertilizer applications that play on those alternate or sensitive crops would be clean there. One thing we also need to be thinking of is the fertilizer mixer, the blender, as well as the tender trucks. Those are something that could be potential causes for contamination somewhat. That fertilizer may be going on to an alternate crop.
Jason: So it sounds like that there’s probably been a little bit more evaluation of this in Louisiana than there has been in Arkansas, partly because, correct me if I’m wrong, that there’s a lot of herbicides, there’s a good many herbicides that go out impregnated on a fertilizer within Louisiana partly because of their water seeded culture that they have here and so is that kind of how you guys came about developing this protocol, this cleaning out protocol and has there been a good bit of testing, I guess, in terms of commercial size testing in that geography?
Drew: So yes, we actually in 2020 put forth analytical or lab testing not only of the batches they are running with their different blender types and fertilizer rates that they use there, can vary as well between situation to situation. We tested those, collected samples, tested those in our analytical lab in Indianapolis to confer concentration as well as clean out processes and then collected samples from those to test for remnants of Loyant and what proved is the two batches of non-impregnated fertilizer running through and the tenders as well as the blenders did an adequate job of eliminating any kind of carryover to a fertilizer onto an alternate crop. 
Jason: Drew if a grower has interest in using Loyant coated on urea, where in Arkansas can they go, how do they go about obtaining the material to get it out to their field, is pretty much anyplace that can provide fertilizer, are they going to have access to this or is it going to be specific from location to location? Do you have any thoughts on that?
Drew: Most all of our fertilizer plants or retailers have the ability to purchase and to bring in supply a premium grade fertilizer. Again we want an SGN number fertilizer, retailers will understand that, an SGN number greater than two hundred to be sure we are at that premium, good quality, least potential for dust to occur. Most can work on obtaining that. I’m not sure of any inpeticular restrictions from that standpoint, however some caution does need to be given again on the blending process. We want to ensure that we are blending this correctly or not dumping all the Loyant into that fertilizer all at once and creating any kind of ?? or clean out problems of the tender because if you dump all the concentrated in there all at once that would cause potential for some machine issues there. Getting it out would be an expensive cleanout. Those are some things that I would invite them as well as making sure they have the correct fertilizer premium grade in our conversations with their salesman.
Jason: One other thing that I want to talk about just quickly before we close is, we did some work last year looking at applying a fertilizer, some of these fields you apply the fertilizer and it may take ten days, it may take five days, some folks can very quickly get water across the field and what I saw in my plots last year is that if you apply this, you want to apply it as close as possible to flooding and the reason being is if you have a rainfall event, a significant rainfall event prior to you actually going to flood, what I saw was if I was ten days out, I’m not going to say that I completely lost control because I didn’t with Loyant coated on urea, but there was definitely a reduction in control if I was ten days out. As it got five days, I’m not sure five days was any different than the day of applying the fertilizer and flooding the same day but in general the closer you can get it to flooding, my experience was the better off you would be. The other thing I would tell individuals is that based on what we’ve seen, the longer you can hold that water once you get that flood established, the longer you can hold that water I think the better off you would be. I mean hopefully you’re not going to have any levies break, but holding that water in that field is definitely going to benefit you. The longer you can hold it the better your weed control is going to be, based on what I saw, at least in my 2020 research plots. What’s your thoughts on that Drew?
Drew: Jason, you’re spot on there, some of the research I had was similar to yours. The closer you were to putting that water, that was in a drill seeded method, again the supplemental label we’ve been speaking on a lot here today, is more for in water use, where you have a flood already established and you slide a coated fertilizer of Loyant into that water, but in my test as well, the closer you were the better. And that brings up a kind of important recommendation here as holding that water and we recommend about ten days holding the water once the treatment’s been applied to ensure that you get good uptake, make sure again that you have seventy percent weeds emerge at the time, watch out for potential weeds where if you lose the water less than ten days, I’d say you won’t get good efficacy and it might be something that could impact that level of control. Really good point there Jason on that. One primary way that Loyant is degraded is photolysis or light. The longer it’s sitting out there on that herbicide, on the surface not being utilized the more likely it is to degrade. 
Jason: So speaking of it being on a surface and wet surfaces, another question that I’ve had from folks is, well you know you can get ammonia volatilization in sense the herbicide is coated on the urea, could you also possibly get a volatilization of Loyant. We’ve known and what we’ve been told as well as the research we’ve conducted, Loyant really does not appear to be a volatile herbicide but could it be co-volatilizing with the ammonia from that urea. So we did a little bit of work where we actually placed it on wet soil, we placed it on dry soil, we even put it in a flood and we saw very little if any volatilization where we actually set plants we’ve set trays of soil that was treated with the Loyant coated urea under soybean plants and again we saw very little if any symptomology on those plants so I really don’t think that’s going to be a concern for us in terms of moving off, but yes moving forward, yes you can get ammonia volatilization from those soils but Loyant doesn’t appear to be leaving there at the same time. So as we close today, Dr. Ellis, is there any parting comments that you have as it relates to Loyant being coated in urea?
Drew: Really we touched a lot of good bases here and I appreciate your sharing your results with your testing and the University of Arkansas is doing a great amount of work again this year. Looking at this drill seeded use, not necessarily row rice but our typical patty rice when we flood behind that application of pre-flood fertilizer and certainly excited about what we’re seeing in some of those results and hopefully going forward Corteva really gone out this year as well and testing commercial like applications in that same method. We look forward to the results that we get and hopefully bring in another solution for the growers to utilize this product in a safer way and benefit from the weed control it produces. So appreciate the opportunity today, we’ve covered a variety of good topics. I’m excited to see what this season holds.
Jason: I appreciate you being with us today and next week Dr. Butts will be providing a podcast and it’s going to be focused on common problems that he’s seen this spring along with the remedies. Again, thanks for joining today and I hope that you found this episode of the Weeds AR Wild podcast series on the Arkansas Row Crops Radio to be informative.