Weeds AR Wild Episode 8, Barber and Steckel, Cotton 4-20-21
Tom: Welcome to the Weeds AR Wild podcast series as a part of Arkansas Row Crops Radio. My name is Tom Barber and I’m an Extension Weed Scientist with the University of Arkansas System Division of Agriculture. 
Tom: Today we are very fortunate to have Dr. Larry Steckel from the University of Tennessee as our guest for this episode of the podcast. Larry is an Extension Weed Specialist and my counterpart across the river. Larry and I talk frequently and compare notes on resistance and which herbicides and programs are providing the best control in cotton as well as many other crops. Larry, very glad to have you today on the podcast.
Larry: Afternoon Tom. Appreciate the invite man.
Tom: Yeah, we got a little rain today so we got some time for, to be down a little it and do some of this. You said y’all are still dry enough to plant today.
Larry: Yeah, the rain seemed to dissipate as it hit the river and so we’re out planting beans right now. 
Tom: Alright, well we won’t take too much of your time. Again appreciate your being on the program. Our topic today is going to be early season cotton weed control and I know Larry talking with Bill earlier today, looks like our cotton acreage in Arkansas is going to be down a little bit from what it was last year, where we may have a little less than five hundred thousand acres in the state and just to cover the technology that’s generally planted in Arkansas, last year I think we were about eighty five percent Xtend and probably around ten or a little bit more than ten percent Enlist. This year it looks like we’re going to be much heavier on the Xtend in regards to which technology’s going to be planted in the state, so we can easily see ninety to maybe even ninety five percent on the Xtend side I think. What are y’all looking at you think? 
Larry: Very similar Tom. Just from the folks I talked to last year, we were roughly eight five percent Xtend cotton. This year from what I hear in the field, we’ll be a lot closer to ninety five percent. So real close to the numbers that you just listed. 
Tom: Alright, well it sounds like a lot of similarities. I know it also could depend, I mentioned, we’re still wet over here. If we continue to be wet and get out of our corn planting window, then we may see more cotton planted. So a lot of it depends on wet in the spring and in regards to how much cotton acreage is going to be out there.
Larry: That’s real common here too. We got good weather so corn’s going in the ground. Usually we have, the past few years, around three hundred thousand acres of cotton but that might be down a little if they can get in the field now.
Tom: Right, right, right. Well good deal. We know, we’re not going to spend too much time here today, but regardless of how many acres we have and what we continue to say in any of our programs, for any crop really, the key in cotton and many of our crops, is we got to start clean at the very beginning. I know a lot of our systems as far as production systems in Arkansas may be different in Tennessee. Y’all tend to have a lot more no till systems than we have currently. But regardless of which system we’re in, those summer annual weeds, especially pigweed and grasses and morningglories, we want them dead, we want a clean tilled field. We want to start clean before we put the planter in the field. 
Larry: That’s true and over here we almost we’re almost no tillage. So starting clean is traditionally been since marestail has become a big issue in early 2000’s Roundup and dicamba and the grasses quite frankly have kind of evolved with that niche and in the last five years grass is getting through the burn down whether it’s ryegrass, which I know y’all have a problem with, but a lot of these summer annual grasses, fall panicum, barnyardgrass, junglerice, goosegrass, they’re slipping through that Roundup dicamba burn down, and even if you come back with Gramoxone right behind the press wheel, it’s too big and you’ve lost and can never just catch up on these grasses.
Tom: Well that’s a great point. We see that a lot. Maybe not as much in a burn down window but I know like you said with the ryegrass this year, our glyphosate resistant ryegrass is spreading through the state from south to north. Every year we get more of it. This year I’ve recommended more two applications for ryegrass control, where we can maybe just go Roundup Select on that first one or go ahead with our Roundup, dicamba or 2,4-D burn down and then come back with Select, but we do a much better job with that ryegrass when we keep the Select in an application by itself without those auxin chemistries in there from an antagonism stand point. 
Larry: We’re seeing that consistently as well. A lot of Select being used. Five years ago there was hardly ever any Select in the burn down, now it’s probably one of the most common used in the burn down. The last five years a lot of the changes have been really dramatic. 
Tom: Right, right, right. And I know, and I’ve seen from some things you’ve released, even later with your applications, with our plant board rules in Arkansas, the previous two years we haven’t been able to tank mix Roundup in with our approved dicamba formulations over the top of Xtend crops, but I can see from some of your work, y’all are starting maybe to recommend separating those out as well. 
Larry: Yeah, we’ve been recommending that for the last two years now and more growers are doing it. In fact I just talked to my consultant a few minutes ago and he said I just never realized how good Roundup worked if you kept dicamba out of the tank. He was actually killing his grasses, so from an efficacy stand point on grasses, there’s just no substitute for keeping dicamba out of the tank. 
Tom: Well and our plant board’s got a comment period right now to decide whether Arkansas is going to go with a federal label or not, but I feel like or I know from my stand point, even if we have the federal label, our recommendation is going to be to keep those separate. One it does cut down on volatility, but two, I mean just to maintain barnyardgrass control & other grasses like you say, I mean we just need to keep those separate moving forward I think. 
Larry: Yeah we do because you might get it in the burn down because dicamba’s hindering that grass herbicide whether it’s Roundup or clethodim. You never catch up. It’s just never going to control post emergence when they get size on them from regrowth. 
Tom: That’s right, that’s right. And it’s crucial for us in our soybean rice rotation. We’re talking about cotton today, but soybean rotation is critical for our rice production acres because in that soybean rotation, we can kill barnyardgrass with Roundup right now. I know y’all are losing control across the river and we likely have some somewhere, we just haven’t found it yet. But being able to kill that barnyardgrass and keep it from producing seed in our soybean years is critical for production of our rice the following year.  
Larry: Yeah, that makes sense. Roughly fifteen percent of our barnyardgrass is glyphosate resistant. And you just never know where it is, it’s scattered around. That’s why we’re just so much clethodim now in with the Roundup.
Tom: Right, right. Well, let’s get back on topic and talk about early season weed control in cotton. I think that we put out a lot of different presentations, fact sheets and blogs talking about residuals and I read yours and we’ve taken a lot of notes on what y’all are doing over there. But for us with all the resistance we have, the PPO’s, our little corners of the counties and various places where we have metolachlor resistance and now we’ve identified gluphosanate resistance in at least three locations. It’s more important than ever to start clean like we said earlier and then come back with effective residuals early on. In the last three or four years we’ve found that including two of those residuals is better than one up front in cotton.
Larry: Yeah that’s true here on our side of the river too. Fortunately we haven’t found any Liberty resistance, but unfortunately Palmer pigweed, we’ve got Palmer now that dicamba will not control and our preliminary research would say it’s also resistance to 2,4-D. So as you all know really the pre got to be thought of as the main weed control program and the post supplemental, not the other way around and going with the two herbicides, traditionally we’ve had a lot of luck like with a pint and a pint of Cotoran Caparol or some of the 24/24 and that’s really worked well for our pigweed as far as consistency from a residual stand point. Now with the grasses becoming more of a problem we’re seeing folks start mixing prowl into the mix or Cotoran Prowl or Brake Cotoran and all of those have been very successful of giving us a good start from the residual stand point on grasses and broadleaves.
Tom: Right and I think I remember you first looking at that pint in a pint of Cotoran and Caparol I thought that was an excellent, excellent idea and we started incorporating it into some of our trials over here and man I agree with you. It is one of our favorites over here. I think those really sandy soils in Northeast Arkansas, Mississippi County, Crittenden County, I think a pint in a pint looks real good in those locations on those silt loam soils like we have around Marianna and other areas and that 24 and 24 looks good. I just think I like putting both of those together. They seem to match well and Cotoran and Brake has always looked good for us. One thing I will say about Brake is it takes a lot, it seems like to me it takes a lot more rainfall to get it going so we definitely need to pair it with something I think. It’s not a stand alone, but I like the Cotoran Brake combination as well, but it’s hard to beat from an economic stand point, it’s hard to beat that pint in a pint of Cotoran and Caparol.  
Larry: It really is and the idea is that Cotoran and Caparol, so you kind of hedge your bet on the weather. If you get a wet spring Caparol will last a little longer, if you get a dry spring the Cotoran will still get activated even though maybe some of the Caparol doesn’t. And that’s the idea of mixing the two. 
Tom: Right, there ya go. And that kind of covering your basis there and something else, you know we’ve seen as even including dicamba with that mix up front. Of course it helps to start clean as long as you don’t have resistant pigweed that is, it helps to start clean. But what it can also do is add us a little protection in case we don’t get that rainfall for ten or fourteen days. You know our spring can be funny and about the time we have it figured out it’s got us scratching our heads, so I like including that dicamba up front just to give us a little time from a residual stand point to get that activated rainfall.
Larry: Yeah, yeah and it will help. It’ll give you a good week any way and just depending on rainfall it may be a little longer. Sometimes two weeks but it will help you there.
Tom: I know that we just have to get out on the right foot and I remember back when Roundup, Roundup Ready System or Roundup Flex Cotton first came out, we kind of did away with the residuals back then and really back in the day Monsanto had to incentivize putting the residuals back in system just so we could get some residuals. But with all the resistance that we have built up now, it’s very, it’s just critical. It’s just like what you said with barnyardgrass. If we miss pigweed on that first application we’re in a fight the rest of the year as well.
Larry: Yeah, like you mentioned, you’re throwing hundred dollar bills at it all year long and still not controlling it.
Tom: Right. It’s just very critical to start clean. I think incorporating these, not necessarily incorporating them, but using these two residuals like we’re talking about in a system up front is really where we are in Arkansas and then you know we often talk in all our programs, within twenty-one days we need to probably be coming over the top, if we get good activation, we need to be coming over the top with a, something with a Group 15 that’s working to help us overlap and have a protection layer early on.
Larry: Yeah and of course Dual and Warrant, Outlook, those are some of the ones thrown out. One of the interesting things is we’ve got a few retailers over here looking at impregnating, fertilize with a Zidua or Anthem Max, pyroxasulfone product. I’m wanting to take a look at it this year, and do some research on it. If you look at the label, the minimum fertilizer you can put out for that is two hundred and fifty pounds, but I got some retailers even thinking about even thinking about building up to four hundred pounds and putting it on corn. So that would be a real interesting way to get another very effective Group 15 in under the cotton without hurting the cotton. 
Tom: Yeah that’s a great idea. I know we don’t want to spray, man I’ve walked beside behind some guys that have actually tried to spray Zidua over the top of cotton when it’s little and that gets ugly, so we don’t want to do that as an actual spray but man I like that idea about being able to incorporate it on some urea or something and possible help us with another protection layer because Zidua has shown to be very effective on our pigweed populations in Arkansas from a residual standpoint. 
Larry: Yeah, here too. Even in maybe some fields where it’s slipping on Dual, Zidua still seems to be the pick of the litter of all the Group 15’s for holding the longest, so getting a little bit of help from that in cotton early on I think will have a lot of benefits.
Tom: Yeah, I agree, I agree. Well that will be interesting to follow. You need to keep us posted on that and I might do some digging and see if anybody’s going to try that over here in our state, so we can follow that as well. 
Larry: That would be good. It would be good for a couple of locations to look at it.
Tom: Right, there ya go, there ya go. What else do we need to talk about? Any other key points you want out listeners to know Larry? 
Larry: I think you’ve kind of outlined some of it. It was sure a blow when you announced that you had Liberty resistance across the river and of course we’ve got dicamba resistance over here. We’re running out of herbicides fast. So that’s why you and I are emphasizing using these pre’s early and often and trying to dial in the best one for the crop and the farming practice.  We just rely spring Roundup and dicamba across these Xtend crops for another couple or three years the dicamba molecule will be worthless and Liberty won’t be any better.
Tom: Well it sounds like we won’t be able to use the Enlist either if these populations are also tolerant to 2,4-D so in three years it’s a scary thought but we could be out of options completely.
Larry: We really could so we’ve got to start managing now so we don’t have that happen in such a hurry. 
Tom: Absolutely and boy have we ever needed some new Ai’s. Good gosh. New modes of action. We need them desperately right now.
Larry: We do. We hear there’s one or two coming but so is Christmas. Lol
Tom: lol that’s right, yeah
Larry: So I don’t know, we’ve got to manage what we’ve got as best we can. 
Tom: Yeah that’s right, that’s right. Larry, we really appreciate you joining us today for this podcast and our podcast series. Appreciate you taking time out of your busy schedule to talk about some of these key management practices. Thanks for being with us.
Larry: Oh yeah Tom, thanks for the invite.
Tom: I also want to thank our listeners and again I want to thank Dr. Larry Steckel. Again he’s an Extension Weed Specialist from the University of Tennessee. Got some great pointers on weed control. Always enjoy following Dr. Steckel and all the information he puts out. Please join us next week on our podcast as Dr. Jason Norsworthy will be discussing weed control in rice and specifically focusing a little bit on Loyant herbicide and some things they’ve got going on and different application methods. Weeds that it’s picking up also potential injury concerns that he’s evaluated. 
Tom: So again thanks for joining us for this episode of the Weeds AR Wild podcast series on Arkansas Row Crops Radio.