 This is Michael Vunch. I'm the plant pathologist at the Carrington Research Center. I'm here at the Oaks Irrigation Research Site, which is a research site just south of Oaks, North Dakota, on irrigated sand. We're in a production belt here that has quite a bit of irrigated production on sands, and white mold is a real problem on the soybeans here. When I started working on white mold and soybeans, I got a lot of complaints from growers and crop advisors that they could not get consistent, reliable control of white mold with fungicides on soybeans, even though they could on dry beans. Now the first thing that we looked at was we looked at fungicide efficacy, but from there we moved on to look at optimizing fungicide application timing. If you look at the previous, the other video that we are producing for this Oaks Field Day on fungicide application timing, you'll find the details of what we learned in those studies. When we completed the fungicide application timing studies, we moved on to looking at fungicide droplet size. Now, as you may know, the standard recommendation for applying a fungicide is that you apply the fungicide with fine to medium droplets, and the reason for this is that fungicides exhibit only local systemic movement. When they are deposited on a leaf, or a stem, or a petio, they move upward from that point of deposition a certain degree, and oftentimes from one side of the leaf to the other. But they only move upward a limited degree, and they never move downward. And so what happens here is that coverage becomes important. If you only get one droplet on the leaf, you're only protecting a part of that leaf. One droplet on a petio, you're only protecting a little bit of that petio. And it's not like an herbicide where the product moves both up and down. And so coverage becomes important. And when you have finer droplets, you get a lot more of them, and you cover a lot more of the plant surface. Now, the problem that we run into for white mold and soybeans is that white mold is a disease that develops on the bottom of the canopy. And if you look at, if you refer to our results on fungicide application timing, you'll notice that unless the canopy closed earlier, you need to be applying your fungicide for white mold at the full R2 growth stage. At full R2, many times the canopy is at or near closure. And the canopy is often 24 to 27 inches tall. The white mold develops usually on the bottom third to half of that canopy. And you somehow have to get your product down into the bottom third to half of a canopy that's at or near closure, and it's over two feet tall. And find a medium droplets while they cover the top of the canopy very well. They do not have the velocity to get inside a canopy that's at or near closure. So we've been running these studies with a tractor mounted R&D sprayer that's equipped with a pulse width modulation system. For that pulse width system, we're able to change nozzles that differ in output while maintaining our overall spray volume the same. We just increase our pulse width as the output of the nozzle increases. And we run these all of the tractors so we can drive at a realistic driving speed. Most of these studies have been done at nine to ten and a half miles an hour. And we've been running them with T-jet tips primarily, but we most more recently initiated trials also with wheelchair tips that allow us to change dropper size without changing pulse width because they have a lineup of tips that changes dropper size without changing output. And what we have learned is the following. When the canopy is open, there's still ground showing between the rows. When the soybeans are at full R2 growth stage, we have optimized the performance of fungicides by applying with fine to medium droplets just like the standard recommendation. This is with T-jet tips. And when the canopy has been wide open, the optimal droplet size has been a droplet on that boundary of fine and medium. I.e. fine but on the coarse render find if you will, medium but on the fine render medium, right at the boundary of fine and medium. That's when the canopy closure has averaged across the footprint of the entire study less than 80%. When the canopy closure has averaged between 80% and 90%, we have optimized fungicide performance with a droplet size that is in the middle of the medium spectrum. When the canopy closure is more than 90% on average, on average, across the footprint of our study, we have optimized our fungicide performance with coarse droplets. And this is anywhere from average canopy closure of 92% to 99%. What happens then is that there is not much ground showing between the rows. You have a pretty tight canopy and then you need velocity. You need a heavier droplet size to get inside. But the important thing to remember is that what our results show to date is that you must choose your droplet size based on canopy characteristics. The more open the canopy is when you're applying the finer the droplet, the more close it is the coarser. And we're not talking ultra-coarse droplets. This is not dicamba droplets. We're talking coarse droplets in this case. And the reason why you don't want to apply a coarse droplet to an open canopy is the finer droplet can get inside an open canopy and it will give you better coverage. You want just as coarse a droplet as the minimum needed to get inside the canopy. This is the last year of these studies. And as you can see behind me, these are very large studies. We conduct these with anywhere from 12 to 16 experimental replicates because of inherent spatial variability of white mold and the need to differentiate small treatments. They're done very rigorously, again with a real-world sprayer at real-world driving speeds. You have any questions? Look at our results online. Google NDSU Carrington. Click on Plant Pathology and scroll down to the section on soybean white mold. Click on the presentation on the impact of spray droplet size and fungicide performance. Thank you very much.