The significance of fungicide alternatives in winter wheat production with Aaron Esser

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Drew Lyon: Hello, welcome to the WSU Wheat Beat podcast. I’m your host, Drew Lyon, and I want to thank you for joining me as we explore the world of small grains production and research at Washington State University. In each episode, I speak with researchers from WSU and the USDA-ARS to provide you with insights into the latest research on wheat and barley production.

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My guest today is Aaron Esser. Aaron is with WSU Extension in Lincoln and Adams counties. He’s been with WSU for 26 years. In conjunction with his traditional Extension program, he has served as chair for the WSU Wilke Farm Management Committee for the last 12 years. The WSU Wilke Research and Extension Farm is a 340-acre facility on the eastern edge of Davenport, Washington, in the intermediate rainfall zone.

Hello, Aaron.

Aaron Esser: Hello, Drew.

Drew Lyon: So, I know you’re in the middle of harvest right now as we record this, at the Wilke Research and Extension Farm, but is there anything that has particular interest for you this year?

Aaron Esser: Yeah. I wanted to talk a little bit about a fungicide study I’ve been working on for the last five years. But before I get into the actual data and stuff, I need to give a little bit of background on it.

A few years ago, I was at a field day and there was a group of farmers talking with Jodi Johnson-Maynard from the University of Idaho–she’s now formerly at the University of Idaho, she’s now at the University of Georgia–and they were talking about earthworms and they were seeing a decreased population of earthworms. And I thought that was interesting and it kind of made me scared because I’ve done a lot with the wireworms and had growers using increased rates of neonicotinoid insecticides.

And I quickly asked her, I’m like, “Jodi, is the increased use of neonics having a problem with earthworms?” And she wasn’t concerned about the increased rates of neonics having an impact on earthworm populations, but she was concerned about the increase in prophylactic fungicide applications with herbicide timing. And I thought that was interesting.

And then I listened to you weed scientists always talk about tank mixing and grassy weed control. And every time you start adding something else into the tank, you potentially increase the risk of reducing the efficacy of your grassy weed control.

And then thirdly, I sit as an ex-officio member on the direct seed board–the Pacific Northwest Direct Seed Association board–and there was an individual, Dr. Curt Livesay from Dynamite Ag, [who] also sat as an ex-officio on the board, and he was working with their product, for no better terms, called “pixie dust” as an alternative to fungicides in winter wheat production.

And when you look at pixie dust, it really does–on the paperwork on it, it’s a potassium silica product that improves plant health and resistance. It’s designed to strengthen the plant tissue, making it more resistant to disease, pest, and weather conditions. So, I quickly got thinking about–and he wanted me to look at that in a trial. So, I said I’d look at it in a trial and then I decided to compare it with fungicides for both stripe rust and foot rot control at herbicide timing.

Drew Lyon: Okay. And herbicide timing being what?

Aaron Esser: The same time, you know, on winter wheat timing being anywhere from mid-April to the first of May in that Davenport region.

Drew Lyon: Okay. And, can you tell me a little bit more about this pixie dust? It’s a potassium silicate product, you said, but what else? Anything else that listeners should know about it?

Aaron Esser: You know, I mentioned a little bit. You know, it’s designed to strengthen plant tissue and make it more disease resistant, pest resistant, and weather resistant. So, with the changing weather and stuff that we’ve been seeing, I thought it was an opportunity to look at something that may or may not be a benefit for winter wheat production here in the Pacific Northwest.

Drew Lyon: It seems to me–when I listen at some of these grower meetings–that some of these fungicides are kind of selling themselves for plant health as well. Besides just controlling diseases, making the plant healthier, it sounds like maybe a similar claim here.

Aaron Esser: That’s a lot of what the claim is: to improve plant health.

Drew Lyon: Okay. So, can you tell us a little bit about the long-term fungicide study you established and what are some of the major findings from the study?

Aaron Esser: Well, we established a study at the Wilke Farm back in 2020 and we really just looked at three treatments. The first one was just water. We threw water in our tank and sprayed it out at 10 gallons/acre. The second treatment was the pixie dust product and we put that on at 18g per acre. It’s kind of a powdery product that you put in the tank. And then the third one was the fungicide. And for this we used azoxystrobin and plus a propiconazole fungicide at 14 oz/acre. And when we went with that rate, that’s a heavier rate for both stripe rust and foot rot control.

The studies [have] randomized, complete-block designs, four replications each year, and the plots are 30 ft wide and 200 ft long. Each of these were run separately, not with the herbicides, but they were applied within a day or two either before we applied herbicides or after we applied the herbicide. But the actual application was just the product themselves going on.

One of the other interesting things when you start looking at fungicides and plants and stripe rust and foot rot, is you need to consider the varieties you’re looking at. And during this–for this study, we looked at it over those five years, seven locations, [and] three of those locations, we had the variety Resilient CL+. That has the stripe rust rating of one and when you look at the disease rating, you know, one has the best resistance and a ten is very susceptible. And so, it has a one. It also has a strawbreaker foot rot rating of three, which is very, very good compared to most of the other varieties.

[In] two of the locations we looked at Piranha CL+ and that has a stripe rust rating of three and a strawbreaker foot rot rating of six. So, you know, [Piranha CL+] doesn’t have quite the disease resistance that we see with Resilience.

This last year we used two varieties, one of them was Sockeye CL+ and that has a stripe rust rating of one and a strawbreaker foot rot rating of five, so, you know, kind of right there in the middle. And then we used a variety called Kraken AX and that has a stripe rust rating of three and a strawbreaker foot rot rating of eight. But, I have to put an asterisk next to that because that’s coming from Lima Grain and on their promotion of this variety, not from the WSU testing yet–we haven’t had it in the program long enough to give it a rating similar to the other ones.

In 2023—I put a little note–we actually expanded the study to include a second azoxystrobin and propiconazole–the same active ingredients, a different formulation. Someone asked me in a meeting, “I’m probably using the right active ingredients, but I’m using the wrong formulation.” So, I took them up on their call and I use their formulation in the study as well.

So, three of the locations, three of the site-year locations had had those two fungicide treatments. Comparing these two fungicides over the two years in those three locations, the p value is 0.99, not 0.09 or 0.05. .99. Highly not significant difference between these two fungicides.

Drew Lyon: So, they basically performed the same in all three trials?

Aaron Esser: They performed the exact–one of the years it was on Piranha and this year was on Sockeye and on Kraken. No significant difference between these two fungicides so the last two years, I lumped those two together.

When you look at the study overall over these 5 years–and I remind you, I’m looking at 28 different locations over these 5 years–so the numbers I talk about [are] not just from one year, [they are] from 28 different locations over 5 years. That pixie dust product has averaged 88.8 bushel/acre. The fungicide application has averaged 88.17 bushels/acre. Putting water in the tank and running that has also averaged 88.17 bushels/acre.

Looking at the treatment by location–so I was kind of getting an idea of was there a different response amongst the varieties that we’re looking at–was also highly not significant, which means that each treatment responded similarly at each location.

Drew Lyon: Okay. What was the disease pressure at these sites? Did you have disease pressure at any of them?

Aaron Esser: That’s a great question, Drew, because that really gets to the heart of it and when I get to my takeaways, that’s one of the things I really want farmers to take a stronger look at and consider. This last year, we had a pretty heavy, high stripe rust forecast for severe damages. I thought maybe we would actually see maybe a spreading this year or a gap in between the check and the water, which wasn’t the case.

Other years it’s been quite low and other years it’s been moderate so that’s one of those things—the stripe rust forecast is one of those things I want farmers to take into consideration when they’re looking at whether or not to incorporate a fungicide or not to incorporate a fungicide.

The other one I’m looking at is foot rot control. And when I look at the farm and what we’ve been doing management-wise, we have a pretty strong rotation on the farm. Some of these were on a three- and a four-year rotation–so we have rotation and we may not have as much foot rot pressure as if you’re running a shorter rotation. So that’s one of the concerns too, that farmers should understand is what type of foot rot pressure do I have on this particular piece of ground or this particular farm that I’m working on?

Varieties. I talked about the varieties, and when I look at–in 2023, the top six varieties planted in Washington state, we go with Piranha’s number one on over 333,000 acres, Norwest Tandem is number two, VI Voodoo CL+ is the number three planted variety, LCS Shine is number four, Impress is number five, and a variety called Stingray CL+ is number six.

When I go through and look at the stripe rust ratings of each of these varieties, Piranha is a three. Norwest Tandem is a one. Voodoo is a five. Shine, Impress, and Stingray all have a stripe rust rating of one. So, when I look at that just from a stripe rust standpoint, the only variety I would probably consider putting a fungicide on would be Voodoo.

Now, if you’re interested in the foot rot, Piranha, as I mentioned earlier, has a six. Norwest Tandem is very good with a three. Voodoo also has a six. Shine, we don’t have a number for. Impress is a four and Stingray is a five.

So, when I look at these varieties, if I would have used Voodoo in my study over the five years, my results may be different. But where I used varieties that you know, the most marginal one I use is probably Piranha for getting a response out of. And with that one, it even wasn’t a response, but it could have been on a different year.

I just want farmers to take that stripe rust forecast, understand the genetics they have out there, and really make a more informed decision. When you look at evidence–you know, kind of get into my takeaways from this–varieties do matter. Maybe the results would have been different if I would’ve used a different cultivar. Understanding that disease history you have in that field. What’s been your rotation? How long is your rotation? Are you trying to shorten it up?

And you mentioned earlier plant health. I’ve seen no–with the timing I’m doing, and I’m not saying fungicides don’t help with plant health–but in the timing I’m applying it with herbicide, I’m seeing no benefit towards plant health. Maybe these results would have been different if I would have tried a different timing. Maybe I can get more plant health benefits if it was at flag leaf timing.

I feel that there is a value in preventing the spread of stripe rust though and that’s one of the reasons, you know, a lot of farmers will put it on prophylactic is by keeping the stripe rust across the whole region down, then you don’t have to worry about the pressure later on. But if you’re planting these varieties, the top six that we have, we have very good stripe rust [resistance] in them so I think some of that’s been taken care of.

If you’re looking at varieties, other varieties, you know, understand what those numbers are.

One of the things I thought was interesting, just looking at it, you know, this year we’ve had a lot of frost. And when I go back and look at years–you know, I said that by location there was no significant difference and there’s not–but some of the things that jumped out at me a little bit looking at the data, back in 2020, the reason I had two locations is we had some pretty severe frost damage in our winter wheat down in the draw bottom. So, I put the fungicide trial in the draw bottom and I also put it on the hill where we weren’t impacted by frost. And once again, I saw no difference with fungicides–but that pixie dust treatment, although not significant, it was a few bushels better than both the water and the fungicide treatment.

This year in 2024, where we had the Piranha we weren’t showing much frost damage. Where we had the Sockeye, we had some frost damage on that. And looking at it, the pixie dust treatment was a couple bushel better where we had some frost damage versus where we didn’t have frost damage. So, when you go back and look at how it helps with some of that weather and stuff, maybe there might be something to it. I’m still not complete with the study. I’m just talking about yield. I still got to look at test weight, protein, and looking at that economic return on investment.

Drew Lyon: Okay, plant pathology/fungicides isn’t my area of expertise, but I hear that…

Aaron Esser: I thought it was everyone’s. [laughter]

Drew Lyon: I heard that a lot of growers will throw it in with everything, because it’s really– the prophylactic treatments don’t tend to be very expensive and rather than go out and do a separate treatment, which there’s money just to go back out there and do that, they’ll throw some in. But it sounds like, in a lot of cases, if you have the right varieties and the right situation, there really is no need to throw in a prophylactic treatment of a fungicide.

Aaron Esser: And I encourage each and every farmer to take a look at it closer in their situation. Add some in, take some out, and see what you get on your farm. And I actually–when I look at these numbers, I still shake my head. I actually truly thought I would see more, especially given the varieties and things like that. And some of the, you know–this year I’m like, “Oh, we got two stripe rust forecast for severe damage. I’m going to see some results this year.” And it was crickets.

Drew Lyon: [laughter] Okay, Aaron, very interesting study. I really appreciate how you listen to what farmers and others are saying and then go out and test some of these things. I think you have a really good ear for hearing what’s being talked about and I appreciate your efforts to go out and see whether you can replicate those using experimental methodologies.

Thanks a lot for sharing this information with us. We’ll look forward to hearing more about it this coming winter season when I assume you’ll be talking a little bit about this.

Aaron Esser: It’ll be one of the presentations or one of the things I focus on in my presentations, Drew.

Drew Lyon: All right. Thank you very much, Aaron.

Aaron Esser: Thank you, Drew.

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Thanks for joining us and listening to the WSU Wheat Beat podcast. If you like what you hear don’t forget to subscribe and leave a review on iTunes or your favorite podcast app. If you have questions or topics you’d like to hear on future episodes, please email me at drew.lyon — that’s lyon@wsu.edu — (drew.lyon@wsu.edu). You can find us online at smallgrains.wsu.edu and on Facebook and Twitter [X] @WSUSmallGrains. The WSU Wheat Beat podcast is a production of CAHNRS Communications and the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.

I’m Drew Lyon, we’ll see you next time.

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The views, thoughts, and opinions expressed by guests of this podcast are their own and does not imply Washington State University’s endorsement.