 Hi, I'm Mike Ossley, the research agronomist here at the Carrington Research Extension Center. Today I'd like to take a few minutes to discuss some of the results and maybe some of the recommendations that we have involving the combination of glyphosate and glufosinate, otherwise known as Roundup and Liberty. In recent years we've had an expanded use of several chemistries in our row crops, not because there's new chemistries, but because the herbicide traits have allowed increased use of some of the older products that we may be familiar with. But only in very recent years have some of these row crops included multiple herbicide resistance traits where we can combine the glyphosate glufosinate in season. So one of the main concerns with this is that there may be some antagonism between the two products and we really wanted to investigate that further. So starting in 2018 we began evaluating the combination of glyphosate and glufosinate on troublesome weeds. In 2020 we've expanded that to include specifically COSHA and at this particular site roughly 40% of the COSHA population is resistant to glyphosate. So it's really a good place to start testing whether or not we're seeing any antagonism between the two products because we know COSHA can be problematic for both chemistries and so what happens now when we start combining both of them together. Let me walk you through some of the results that we've found so far. Just to clarify some of our treatments, the COSHA that was sprayed out here was roughly two inches or less when we made the applications. Currently the COSHA is quite a bit larger than that and it just grew that much here in the last couple of weeks. But that's been the goal is to try and come into these studies with timings where the product should be effective. In the past years when we've had common lambsquarters or wild buckwheat the same is true. We're generally dealing with four to eight leaf weeds when we spray them so big but we should be able to still get that effective control with either product. So moving on to the results. We have a couple of years now where we're able to get some good evaluations of weed species using both products alone or together including some combinations that include in list. So what we tried to do was use a standard rate of 32 ounces of Liberty and 28 ounces of Roundup PowerMax as our standard and then we would either reduce the rate of the Roundup or increase the rate of the Liberty in certain situations to see if we can't tease out some differences. So in this first slide we have several weed species and looking at evaluations both soon after application and then sometime in the future. A couple of the first things to note here where we saw some really big differences in the past is looking at wild buckwheat actually that's one of our key species here because it was in fact the only instance we've had so far where we've seen a benefit to combining the products. So in this case we had really fast and good control with our initial Liberty application creating a situation where there's 80% or more control and it was kind of cool when these applications were made and so they took a while for the glyphosate to catch up but if you skip ahead from seven days over to 21 days you can see that and long run the glyphosate still provided very good control. Now when you start looking at the different combinations of treatments there wasn't a lot of difference between the different rates but we did see the fast acting Liberty show up on all the evaluations but with the glyphosate that activity was maintained through 20 days after application whereas with Liberty alone the control started to be reduced and so you kind of got the benefit of both the Liberty and the glyphosate so that is our one example where we saw any kind of benefit to combining them. Most of the time whether we're talking about common lambs quarters or some of the other weeds we saw no benefit but no real antagonism. Now the other two species on the slide both the kosha and the green foxtail we saw situations where we had reduced activity when we had the combination compared to either product alone and so with the green foxtail which we know the roundup is should be really strong on we indeed saw a very good activity and Liberty which we know will not take out the green foxtail on and so on struggled a bit but then when we combine them we mostly just control rating between the two so a clear situation of the Liberty antagonizing the activity of the glyphosate and we saw something a little similar with the kosha and this was in 2019 neither products performed very well on that application but then when we combine them the the final result was even worse and so and that's really what led us up to our 2020 trial. In 2020 we wanted this trial to specifically focus on glyphosate resistant weeds and the site we're working on has glyphosate resistant kosha and roughly 40% of the population is surviving our glyphosate application so we still have a fairly high amount of the population that's susceptible and then some that isn't. We also have similar trials occurring at other sites that involve both kosha and water hem and we'll be able to summarize those here at the end of the season but for now the the story on this particular site is pretty straightforward. We have a really good activity with our Liberty here and in fact upwards of 90 to 95 percent in all of our replications of this treatment and when we look at our glyphosate then our glyphosate treatment is certainly showing a lower percent, roughly 60 percent control over the entire plot area and the story is simple because when we look at applying both products together at any rate in any combination the Liberty is really driving the control and so since with Liberty alone we were getting already 95 percent control whenever we had Liberty with glyphosate we were still always getting roughly that same amount of control and we really don't have any instances where the glyphosate was negatively impacting the Liberty and that's not really what we'd expect anyway. If we're going to see antagonism it's going to be the Liberty antagonizing the glyphosate. We don't expect to see the glyphosate antagonizing the Liberty because the Liberty is fast-acting it's going to burn back that tissue fast and so if you see antagonism with the two products combined it's going to be because the glyphosate wasn't able to get into the plant before the necrosis occurred and the leaves dried up and so that's why when we are using this system we really want to tailor it to our Liberty application. We want to pretend like we're applying Liberty and you just happen to have some glyphosate with it to improve some of the grass weed control. Your other options would be adding something like a select or or an assure for that grass control anyway. So the bottom line is the story is not very simple because we have many situations where we saw no benefits to adding both products together and we have several situations where we're seeing some antagonism often in the range of about drop of 10% in control and we have only one instance where we saw benefit. So if a person's looking to make an application with both products you just have to understand that it may not be economical in most cases. The best management practice is still to lead with your Liberty and follow it up with your glyphosate application on your next pass. You want that Liberty early in the season to help take care of all those early emerging weeds when they're small and then later in the season follow it up with the glyphosate application to help clean up any stragglers. Thanks for listening in. I hope you enjoyed this and good luck controlling those weeds this year.