Weeds AR Wild Series, Season 2 Episode 6. 
Title: Herbicide Resistance Concerns for Arkansas Rice
Date:  March 24, 2022

[Music]:  Arkansas Row Crops Radio providing up to date information and timely recommendations on row crop production in Arkansas.

Jason: Welcome to the Weeds AR Wild podcast series as a part of the Arkansas Row Crops Radio. My name is Dr. Jason Norsworthy, and I'm a distinguished professor of Weed Science with the University of Arkansas System Division of Agriculture. And today, I'm excited to be joined by Dr. Tommy Butts, our Extension Weed Scientist. Hey, Tommy, it's great to have you on this episode of our podcast.

Tommy: Yeah, thanks, Jason. I appreciate being here to be able to talk about the wonderful topic of herbicide resistance in the state.

Jason: That is correct. We will talk a little bit about herbicide resistance today. So, you know, with that, I think today, Tommy, you told me you were talking before we went live with this podcast. We're going to focus today's podcast on herbicide resistance issues associated with rice. And I think we'll follow that up next week. We're talking about some weed issues outside of rice. You know, when I think of rice weed control, Dr. Butts, we did a survey, I guess, what, about a year and a half ago now. The number one weed of rice, everyone in the state of Arkansas understands what that is. That's barnyardgrass.

Tommy: Yeah, it was an overwhelming response. I mean, it was basically every single respondent had that as their number one weed both in and flooded and row rice. I mean, it’s a problem in both systems.

Jason: That is correct. You know, it's hard for me not to go around the state. And you look at fields, there's very few fields in which barnyardgrass does not exist within rice. And we've been doing a screening. Actually, I can think back when I was a graduate student at University of Arkansas, back in the mid nineties, I remember us even doing a barnyardgrass screening at that point. With Dr. Ron Talbert. And it's amazing what's happened over, I'd say the last 25, if not 28 years. Propanil really is what triggered this screening. And it's just amazing when I look at the numbers today and see where we were 1990, 1991 with the first cases of Propanil-resistant barnyardgrass to today. When I am sitting here looking at my numbers in 2022, which would be the 2021 samples that we evaluate, we had 51 barnyardgrass samples that came in this year. Of those when I take a look here at the numbers, 76% of those three out of four samples tested positive for Propanil resistance. And you know it's just gotten to the point where today, Propanil is not a barnyardgrass material. It's hard for me to say that when I think back to in the eighties, even in the early nineties. Really Propanil was the cornerstone of what we did for barnyardgrass control.

Tommy: Yeah. Whenever I get phone calls too, most of the time, I'll ask the question just to check when it's pretty much like, “oh, yeah, propanil doesn't kill or doesn't touch our barnyardgrass.” There's some pockets I think I can find in the river valley where it still works. Maybe just right on the west side of the ridge. You know, there's a couple of little pockets where it still can be successful, but it's real limited. I mean, it's like you said, the 76% plus seems about right to me where in the majority of cases it’s not working anymore more for barnyardgrass.

Jason: Well, and again, I don't want to make this a weed control talk. This isn't necessarily to say the Propanil is not a valuable tool for us in rice. I think it really is. I know I've done a lot of work on sedges. You've done a lot, you've done a tremendous amount of work on sedges since you've got here, and this is still a valuable tool for the Arkansas rice grower.

Tommy: Yeah 100%. And some of the weeds we talk about later, where we've gotten away with using other chemistries and now we have resistance - our next option, our fallback option, comes back to Propanil. So yeah, like you said, it may not be a barnyardgrass material anymore, but we're going to be using it a heck of a lot in the near future here for multiple weeds that are resistant to other herbicides. Yeah. It's still going to be a real valuable tool in the toolbox.

Jason: Exactly. Another herbicide that we have in our screening program, and it was really the second barnyardgrass resistant weed that we found within the state is we have Facet that we screen for. And, you know, as I've looked at these numbers for the past three or four years, what's interesting is, every time that I find Propanil resistance I almost always find Facet resistance within that same population. And I don't know if it's just because we had used Propanil on some of these fields.  And when Propanil failed, we kind of switched to Facet. I'm talking about like in the late nineties or early 2000s. But looking at my numbers here, 78%, almost identical percentage, we had Facet resistance. This Facet-resistant number has really exploded over the last five years. The Propanil has definitely increased substantially as well as Facet. And you know, I've gotten to the point today when I think about Facet and think about barnyardgrass resistance, I'm a bigger fan of, if I'm going to use Facet, I want to use it at planting, because on these resistant populations we still have some activity on a Facet-resistant population. Whereas if that barnyardgrass emerges, Facet or any other form of quinclorac, I mean, absolutely no activity at all. What are your thoughts about that?

Tommy: That was exactly what I was going to ask you next. My main recommendation is move Facet up with Command and use the residual out of it. Because I still see great residual control out of it. And adding, even if it's only, let's say, 60% on a resistant population, adding 60% to what Command gives us is awesome. So I love it up front in the residual standpoint. And like you said, just from a POST perspective, I just don't see success out of it any more really at all. And so I'm with you, I like moving it up and the fact that even if we have a technically resistant population POST, we still get residual activity, that's where I'm all about it too. So yeah, I definitely agree there.

Jason: Well and I think the guy that's using Facet postemergence, if he's banking on Facet to give him postemergence control, I see you getting into a salvage situation rather quickly because it looks like based on the numbers, the chance of it failing is extremely high. Now all of a sudden I'm probably pre-flood or post-flood with very, very large barnyardgrass and you're going to spend a lot of money trying to control big barnyardgrass.

Tommy: Yeah. And even then in the salvage situation with Ricestar POST like that - the last couple of years we've had a couple of salvage studies and even Facet then it mixed with other things hasn't looked great in a salvage situation. You know, we could do some things like Ricestar and Regiment and get some really good control on big barnyardgrass in a salvage situation. But like a Ricestar and Facet, a Clincher and Facet, it’s not the same level of control. You really don't get anything extra out of it. And so, yeah, I'm 100% moving it up earlier in our season and using the residual as much as possible out of it.

Jason: So you mentioned Clincher, you mentioned Ricestar. I include Clincher in our herbicide screening within the barnyardgrass. And when I'm sitting here looking at the numbers today, 22% of the samples this past year came back positive for Clincher resistance. I think it was 12 of the 51, 12 or 13 of the 51 samples came back as positive. You know I was really kind of shocked and taken back. Me you had spoken a couple of days ago about this, and prior to this year I probably had 15 maybe 20 samples and tested positive for Clincher resistance. And I'm seeing that number, the same as what we talked about a few moments ago, with Propanil, with Facet. We're seeing that number starting to creep up and you know that's really a concern. When I think of Clincher resistance, one thing I want to make sure our audience understands, is we've done a lot of work to look at Clincher. And then we've taken samples and also sprayed those with Ricestar. And if Clincher isn’t going to work, I can assure all of our listeners that Ricestar is also not going to be an option. And someone might say, well, “what about Provisia? Provisia herbicide or even Highcard? Highcard is going to be available this year in Max-Ace rice. We have seen some positive results with Provisia and Highcard. It's not a guarantee that those are going to work. We have had some misses there. But overall, we have a lot more activity with Provisia or with Highcard on these populations that have tested positive for Clincher or for Ricestar resistance.

Tommy: And that Clincher and Ricestar resistance, is that localized in a certain area in the state?  Is it mainly northeast? Is it all over? Where is that?

Jason: Well I've seen, like I said now we're probably up to 30 samples, I’ve found it all over. I can't point to one area and just say, hey, it's localized . So, it’s not to the point where that I think we're going to go out and we're going to have a tremendous number of failures. When I look at 22% this year on Clincher, and again Ricestar would be the same number, everyone has to remember that, it’s not that 22% of our barnyard populations are resistant to Clincher and resistant to Ricestar. We are only getting samples from those that fail. I laugh and tell folks I've never found a resistant weed. If you have effective control of it, and if your program works, folks don't send me seed and say, “hey, I got it in the bar ditch, but I killed it out there in the field.” We don't get those samples. So I think the number is definitely much, much lower than the 22%, but it is a concern seeing that number is starting to creep up in the last couple of years. You know, another herbicide that we include in the program that is used to a great extent. I've got Newpath in here, and this past year 49% of our samples tested positive for Newpath resistance. Does that surprise you, Dr. Butts?

Tommy: Not really. I get those calls all the time, too, where the ALS chemistries don't seem to be working anymore. And I pretty much just say, yeah, that's where we're at in life with it when it comes to it. Both on barnyardgrass and weedy rice anymore, too, for that matter. And I know we’re going to talk about that in a little bit, but those ALS chemistries just don't seem like - seems like we're losing them every single year by quite a bit. And you know, you mentioned Newpath and you mentioned that. The FullPage system is no different when it comes to the weed control. And so we wanted to highlight that too, you know, Newpath or Preface – well they’re one in the same. You know, they're the same active ingredient. We could spray one, and neither one's going to work. If it's resistant, it's resistant to that chemistry, which is both of those herbicides. So, switching from Clearfield to FullPage is not going to give us an answer if we have resistance in our barnyardgrass or weedy rice. They're both going to fail for us. And I think we've seen that now in multiple places across the state, too.

Jason: Yeah, and in the past I've included Loyant within the herbicide screening program. 16 ounces of Loyant, there's not a lot of growers based on my conversations with growers, there is not a lot of growers out there today that's using 16 ounces for barnyardgrass. We’ve had some issues in terms of putting it out of a plane at least in terms of spraying it. We've had some issues in terms of controlling barnyardgrass with it. I've talked about that for the last several years. So this past winter I made a decision to drop Loyant from the herbicide, the barnyardgrass screening program, and I added in Regiment. One reason I added in Regiment is we have a tendency to talk about ALS-resistant barnyardgrass. You just kind of grouped things in together. And I was really wanting to know, is Regiment a more effective herbicide than Newpath.  I did some reading and looked at some mutations. I’ve talked about this those of you that haven't had a chance to watch the Arkansas Crop Management Conference Rice presentation, I talk about differences in Newpath and Regiment there. And what's interesting is when I go back and look at all the numbers for this past year I told you I had 49% of the samples tested positive for Newpath resistance. Only 14% of the samples tested positive for a Regiment resistance and that really does not surprise me considering the fact that almost any mutation that we have in barnyardgrass resistance, every one of those leads to Newpath resistance - but only two of the four lead to Regiment resistance. And what I see here that also tells me that the likelihood of those mutations occurring is rather rare. And when I hear from growers, and I'd be interested to hear your thoughts, when I hear from growers or applicators, I don't hear nearly the number of complaints with Regiment failures versus that of Newpath or Preface.

Tommy: No, 100%. It's interesting to hear like that. You know, the mechanism or the markers or that kind of stuff that confers some of that resistance, because it matches up with the field observations, in my opinion. You know, I see a lot of people having resistance or troubles with the Newpath Prefaces of the world anymore or you know, also the Beyond and Postscripts of the world. I mean, those fall in that same category. And so, you know, I hear a lot of failures from that standpoint, but then you get to Regiment. And man, it's not to the same level. You have a handful of guys that will have trouble with Regiment and it may be resistance, it may be just kind of, you know, temperature, you know, moisture effects later in the season when they're going out in poorer conditions, those kinds of things. But just much less complaints on the Regiment front than some of those other ALS chemistries. And so that it's very interesting to hear how well that matches up with field observations. That’s pretty cool.

Jason: You know, another herbicide that I include in the screening is Clomazone or Command. You know, any time you hear me get up and talk about rice, I'm going to say it all starts with Clomazone. You can put with it what you want. But at the end of the day, if you don't have Clomazone on that acre to start, you’re behind the eight ball when it comes to barnyardgrass controlling. You know, I'm excited to tell you that this year we didn't find any Clomazone resistance and you know, again, going back probably a thousand samples over the last ten years. We're probably somewhere around 10 or 11 samples that have come back positive for Clomazone resistance. And I was giving a talk here recently and someone asked me said, well, “why is it that you screened a thousand and you only have ten Clomazone-resistant samples, when you talk about Propanil blowing up, Facet blowing up, and we talked about Clincher, Newpath, and all these others blowing up?” And really I think the reason behind that is, is because we start with Clomazone. If for some reason Clomazone does not work, we come back in with postemergence herbicides and we try to prevent those plants from setting seed. These other products we're talking about - Clincher, Propanil, Facet, Newpath, these are herbicides that we're using in the postemergence program. And, you know, when they fail, we have difficulty preventing seed production. And if you don't prevent seed production, those populations can increase rather quickly. What are your thoughts about that?

Tommy: Well, I would agree with that, and I was just going to ask, do you feel that's one of the main reasons why we haven't really heard complaints or, you know, had a major screening step towards Prowl and Bolero yet either? Why those are still successful residuals for us?

Jason: I think so, too. You know, Prowl and Bolero, those are two products I mean, they're strictly residual products. We try to use them early. I mean, even if we use them early POST, we're using them for residual control. We're not putting postemergence selection on our barnyardgrass populations with those herbicides. And you're correct. I appreciate you bringing that up. I mean, those are two herbicides that being Prowl and Bolero - absolutely no cases of resistance that I'm aware of at this point, as it relates to barnyardgrass, at least here in the midsouth.

Tommy: Yeah. Now, I've heard a few rumblings from growers saying that, you know, it may be on the horizon, that they feel like they're getting a little nervous about it per se, but nothing to the extent of especially like our postemergence products. In the Clomazone front, I rarely hear anybody tell me that they’re concerned right now with Clomazone resistance other than just a few handful, like you said, the ten out of a thousand basically.

Jason: You know, the last herbicide that we include in our barnyardgrass screening program is glyphosate or Roundup. Folks keep asking me, when am I going to find glyphosate-resistant barnyardgrass? I mean, when is it going to happen? You know, it's over there on the other side of the river. I've had an opportunity go over Tennessee and it’s the real deal, I mean, I’ve seen it there and they truly have resistance. You know, this year our samples come back with absolutely no resistance. Now, having stated that, I do think that we're on the verge of losing the battle, even though we don't have resistance to date. One thing that I've noticed in my work is that, and I'd be interested to hear what you're seeing, but when I go, and I spray glyphosate or Roundup. We'll spray a 1x rate in the greenhouse and we kill everything. And when we start backing that rate down, we can definitely see that there are populations out there that are highly sensitive. There are some populations out there, when I go to a 1/2x rate, I may get 60% control, 70% control. Where a 1/2x rate provided 100% control of some of these other populations. And what concerns me there, Dr. Butts, is that some plants that are three to four inch in size and you get out there in the field and you're out there with a six-inch, seven-inch barnyardgrass plant and then all of a sudden I'm not getting good coverage or I mixed it with Clomazone, Command. We've done some work where you mix those together and you can get some antagonism. Now, if you’ve got a highly sensitive barnyard population, that's not an issue. But if you've got one of these less sensitive populations, that does become an issue. But as of today, I don't have resistance. What do you hear and what are you saying in the field?

Tommy: Now, that's the same thing I hear, complaints and concerns about it. But any of the ones that I've collected and done just a quick rough and dirty screening on, there's nothing that I could say that I would confirm resistance on. Now, the reduced sensitivity or those kinds of things, I would agree right there with you. I've had a couple of populations where I first sprayed at a lower rate or, like a 22 ounce rate, which is technically labeled, but it's real low and nobody really uses that anymore. And I've only seen, let's say 75% control out of it, which is kind of scary in a greenhouse when you should be smoking it. But as soon as I upped it to a quart rate, you know, it was gone, it was smoked. And so, you know, I haven't seen where a quart rate has not taken out that population yet. But like you mentioned, I think there's some of that increased or you know, reduced sensitivity. And then if you start pairing that with bigger weed size you know, poor water quality, we got a few places out there in the state where we've got real hard water, and if we're not mixing in things to kind of correct that in advance, that can tie up some of our glyphosate and just compound the issue. And so I think when you get some of that increased tolerance, all of a sudden you have these other little factors that really add up and you can see pretty significant losses in control and it's funny, you mentioned Tennessee. I was actually just recording a War Against the Weeds podcast with Joe Ikley and Dr. Steckel today. And we were talking about that resistant barnyardgrass over in Tennessee. And I told him, keep it over on that side of the river. We didn't need any more stuff coming from Tennessee to the Arkansas side. So, I told him, I don't want to blame him for another weed species resistance over here.

Jason: I'll tell you what, it's a real deal. I've been over there and I thought about burning my shoes [laughter] before I came back across the river after seeing that barnyardgrass over there. So that kind of summarizes where we are on barnyardgrass. Want to quickly move over and hit on a few other weeds that we have of rice that are important you know, one that we always think about associated with rice is weedy rice. Sometimes we call it red rice. Of course, today we have these off-type hybrid rice that really have weedy characteristics with them. And so, you know, this past year I had 14 samples that came in. We tested those for Newpath resistance, and 93% of those, 13 out of 14 of those, tested positive for Newpath or what I'm going to say ALS resistance. Again Newpath. It's going to be Newpath, Beyond, Preface, Postscript you're going to see a resistance to those. We also took this year and elected to spray those with Provisia. I'm excited to tell you that we killed all 14 of those with Provisia. It's just getting to the point I hate to say this, but it's getting to the point where the utility of the FullPage system or even the Clearfield system for weedy rice control, I mean, I just question why a grower would plant that or a lot of growers would plant that for the control of that weed. You mentioned a few moments ago, you're kind of seeing some similar things as it relates to weedy rice.

Tommy: Yeah. Weedy rice and barnyardgrass for that matter. I mean there's a lot of failures anymore on that front too. With both of those weeds for the Clearfield/FullPage system. So it's, definitely a challenge. Just to kind of hit on some control measures for both of those weeds, because you can kind of group them together to some extent when it comes to barnyardgrass and weedy rice. You know, we're really focusing a lot of efforts on recommending, especially in barnyardgrass, get those residuals out and overlap those residuals. Make sure we have those on hand and just never let it out of the ground, you know, the Commands and Facets of the world up front. The Prowl and Bolero's overlapping. You may get a little bit of residual out of Newpath even on a resistant population, but not to the extent with like Facet because it's typically more the target site which just confers no matter what. So, you get hit or miss on that end. But get those residuals out, get them up front and that'll help out a lot. And then as far as post perspectives, if we start getting into these multiple resistance factors for both barnyardgrass and weedy rice, and you have a real bad dense population, at this point, it's highly advantageous to consider the Provisia or Max-Ace systems - and get that other Group 1, that quizalofop as an option postemergence to try and kill some of that stuff. As well as maybe still working in the Regiments of the world, POST and things like that, that might still be effective too. Not that Regiment can work on weedy rice, but the barnyardgrass side there. When it comes to the weedy rice, if you’ve got a bad population out there, more likely you're really going to want to consider that Provisia/Max-Ace system to help you out.

Jason: Well, along those lines. You know if we go back to the early 2000s, Clearfield Rice came along and you know there was some concern. ALS resistance evolves rather quickly, and actually I was surprised to see how long that technology lasted. And it really wasn’t, as far as my thoughts on this, it really wasn't until we started incorporating Clearfield hybrids in there. With the hybrids you have this shattering and you have these off-types and that's really where, as far as I'm concerned, the term weedy rice really originated. Because then you had the red rice, you had these off-type hybrids that were in the field that you couldn't control the following year. And I guess the only reason I mention that is, you know, today or up until this point we've had Provisia, which is inbred rice. We've had. Okay. So you've also got Max-Ace but now with Max-Ace, you're going to have an inbred Max-Ace and you're also going to have a hybrid Max-Ace. So, as I look down the road and I'm looking to three, four years from now, I'm a little bit concerned as to whether we're going to generate these off-type Max-Ace hybrids that we can't kill with Provisia herbicide or with Highcard, or quizalofop, regardless of what the formulations are, that is a concern in the back of my mind.

Tommy: 100%. And I think that's where we really need to stress the rotation factor, and make sure everybody is following those stewardship guidelines and working through those systems. And that is one place where the FullPage system can still be really a benefit. You can work that different system in, and you don't necessarily have to spray the Preface, because the labels are written a little bit differently you could do a Postscript only program and then that doesn't pigeonhole you the following year. You could grow conventional rice or Max-Ace rice or Provisia rice that following year because you didn't have to spray that Newpath or Preface up front there. So that would be, again, there's a way to make that whole system work and have the rotation factor and try and work in soybeans into that rotation as well. And that will go a long ways at delaying that evolution resistance as well.

Jason: Sounds good. You know, the next weed that really pops up on the radar is the second most problematic, I’m going to say a group of weeds. Second most problematic weed of flooded rice we talk about is sedges. Me and you have already just mentioned that a few moments ago, but you know, ALS-resistant rice flatsedge. When I look at our numbers and what we're seeing in our screening program, today about 90% of what comes in tests positive for ALS resistance from a rice flatsedge standpoint. Then also we have yellow nutsedge. And last time I counted I'm going to say three to four populations that's what we have in Arkansas that's ALS-resistant on the nutsedge front and that has been isolated, at least as to what I have screened at this point, that's been isolated mainly to northeast Arkansas. Whereas the rice flatsedge - if a grower has that, I don't care if it’s northeast Arkansas, south Arkansas, it’s everywhere. I know you've done a lot to try to address the sedge issues. What are your thoughts on that?

Tommy: Yeah, 100% agree. I mean, I just assume basically the rice flatsedge is ALS-resistant when I start talking about control options across the state. We've done a real concerted effort over the past year or two here to try and make sure everybody knows how to ID especially those two apart, because our control measures are pretty drastically different now since we have the widespread ALS-inhibitor resistance in rice flatsedge. You know, that yellow nutsedge, the best option is still the Permit, Permit Pluses, Gambits of the world, using those ALS chemistries to get it under control. Since the resistance is pretty limited, they're still real effective and so those are the best options for us. But with rice flatsedge we’ve got to go away from that, because of that widespread resistance. So being able to ID those two is really important. And when it comes to flatsedge control anymore, from a residual standpoint, my best one is always Bolero. Sharpen can add some. Facet adds a little bit if you get some mixes with it. But you know, really Bolero is the best residual option there. And then from a POST perspective, we fall back on the Basagran and Propanils of the world. Again, this is where Propanil has some utility for us. And Loyant, can still be very effective too, in the right situations where guys can get it out, where they can use it effectively, those kinds of things. And so that's really where we're falling back to you on a POST side. In the yellow nutsedge world, if we do have ALS resistance, we still have options but they're not as good of options as before. You know, Bolero, from a residual standpoint, can help. It's not a home run, but it can help. League is the best option from a residual standpoint, if we don't have ALS resistance. But once we get that, League goes out the window too. You kind of fall back to the Bolero again. From a POST perspective, Basagran and Propanil can do a decent job, especially if it's small. It can burn it down. But, you know, once it gets a little bit of size to it, more likely you're going to have to hit it probably twice to burn it back. Same kind of goes for Loyant. Loyant can work on it, but I tend to say it's going to take two shots to really kill it out if you want to try and kill it. So it gets a little bit iffy on the yellow nutsedge side when we've got ALS resistance.

Jason: Yeah. And then another herbicide that we now have a federal label for is Rogue. So I mean, again, I do not recommend to anyone that you have rice flatsedge in your field and you sit there and say, “well, I'm going to let the stuff grow and get to six, eight, nine inches and then flood up on it.” But as you're going to flood, if you know that you have rice flatsedge in the field, Rogue is a very effective option. The one issue you run into with Rogue, I really think that herbicide is tailored for zero grade, it’s tailored for side inlet. An individual that's going to have a lot of levees in the field and is pushing water out tell them this is not a herbicide for you because if you push water you're going to push herbicide. So in those situations that is a tool that we have in our tool basket to help us control this flatsedge.

Tommy: Yeah. 100%. And it's real it is real effective for our rice flatsedges of the world, a little bit less effective for the yellow nutsedge side. But annual sedges, it's real good on.

Jason: Yes. So two more weeds just want to hit on rather quickly and then bring this to a close up Pennsylvania smartweed you know, I've done some screening on that. I've done a little bit out of the bootheel of Missouri, as well as northeast Arkansas. I think I found, if you consider the bootheel as well as northeast Arkansas, three or four populations that is ALS-resistant. When I say ALS-resistant, there I am talking Regiment. I'm talking Gambit, Permit Plus, Permit. We've screened one again this year that we found, I think in Mississippi County. You've done some work to confirm some ALS resistance. You would agree again, it's not widespread. I mean, pretty isolated. Northeast Arkansas, but it's a concern.

Tommy: Yes, definitely. And, I would say it's spreading because I get more and more calls on it each year and concerns about it. And so I think it's definitely spreading. I'd be on the lookout for it. And like you mentioned, I mean, it's everything. It's Gambit and Regiment you know, it's the Permit, Permit Pluses - like none of it works. And when I say none of it works, I mean none of it comes close to work. And I think the population I screened last year, the highest rate I used was an 8 X rate, which is still pretty darn high. And they didn't touch it. It maybe stunted it slightly and it just grew right out of it. So when we're talking a four-ounce rate of Regiment and it stunts it back a little bit, that's a big deal. You know, not none of those ALS’s are going to get it. And so we really fall back on trying to control that thing. If you have that resistance, again, it's not great options, but it can be successful if you hit it right. Again, the Basagrans and Propanils of the world will burn it down and keep it in check, if you hit it early and you hit it maybe with sequentials. Loyant is less effective on it. I'm not sure, is something like a Grandstand, does that help at all on the smartweed? 

Jason: It’s not going to do a lot.

Tommy: Yeah, okay. I typically fall back on the Basagran and Propanils of the world to try and burn it down. That's really been my number one recommendation. If you've got that resistance or concern for resistance in it.

Jason: Yeah, that's correct. And like you said, it'd be better to be small. If it gets some size on it, you're going to have some difficulty there. The last weed we are going to cover today, and then we're going to wrap this up.  Sprangletop, that's again, one of the top five weeds that we have in the state. It's been a couple of years ago now, I found some ACCase resistance with probably one or two populations. I didn't test any this past year, but we do have some ACCase resistance out there. And this one's a little bit different than what we see with the barnyardgrass. Actually I looked at Clincher, I looked at Ricestar, I looked at Provisia, I looked at Poast. I mean, what I saw in terms of the resistance, it was resistant to basically any ACCase herbicide that I had in these couple of populations of sprangletop that we've seen the past. And I guess what concerns me when I sit here and say Poast or I say the Select type products, I mean, not that we're using those in rice, but when we go to soybean and we may be trying to use those in soybean we can't control this. That's really a concern.

Tommy: Yeah, that’s really limiting options across our rotation, and it's kind of thrown out the rotation effect where we can kill some stuff. So that's difficult to hear. Where those mainly, I think you told me, but these were mainly in South Arkansas?

Jason: These were in south Arkansas. I confirmed one out of Louisiana, and I think there was one or two in South Arkansas. So again, not something that's widespread. It is something that we're keeping an eye on, especially as you expect the Provisia and the Max-Ace rice acres to increase. There's going to be more and more selection pressure on that type of chemistry.

Tommy: Yeah. And I would just say keep a lookout on that, too, as far as spreading goes. Because again, we're talking about mainly south Arkansas. But I know last year when I was driving around Clay, Green Lawrence, Randolph Counties - last year for some reason just had real bad sprangletop. I mean, there were a lot of escapes last year, and last year was a strange year. We have strange years everywhere. So it maybe that we just chalk it up to the year it was, but it just seemed like last year, sprangletop had a heyday up there last year, too. And whatever the reason was, I'm not sure. But, you know, again, it seems like randomly you'll have some real bad pockets of sprangletop anymore too out there. And again you know our best control methods there still in our typical grassers. But, again, overlaying residuals. If we can get residuals out, overlap them. Especially that overlap in later postemergence residuals is really what catches a lot of that sprangletop because it tends to be a later emerger on us. You know that's the best ideal situation make sure we're laying some of those overlapping residuals, and that'll help us out there too.

Jason: That is correct. I see it a lot of times coming up right as we're trying to go to flood, where we've got it coming. So, with that Dr. Butts’, I want to wrap up today's podcast. I want to thank you for joining again, this podcast. And hopefully again next week, me and you can get together and we can do another podcast and we can we can focus on some other weeds outside of rice. I really enjoyed talking about rice, talking about solutions for rice growers. So again, thanks for being with us. And I want to say thanks to those that are listening to this podcast. Thank you for joining this episode of The Weeds AR Wild podcast series on the Arkansas Row Crops Radio.

[Music]: Arkansas Row Crops Radio is a production of the University of Arkansas System Division of Agriculture. For more information, please contact your local county extension agent or visit uaex.uada.edu.