235: Battling Fungicide Resistance with Glove Sampling

To understand fungicide resistance in the vineyard, a group of United States scientists formed the Fungicide Resistance Assessment Mitigation and Extension (FRAME). Sarah Lowder, Assistant Professor and Viticulture Extension Specialist at the University of Georgia describes a nationwide sampling project to test for resistance markers. To get samples, they are promoting a new collection method called glove sampling. This process leverages the time that fieldworkers are in the field running their hands through the vines. They collect samples by rubbing their gloved hands on a cotton swab and sending the sample to the lab. Research shows that glove sampling results are very similar to spore trapping, a process that samples the air flowing through the vineyard.


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2024-07-04_235_Sarah Lowder - glove sampling for mildew_Otter

[00:00:00] Craig Macmillan: Our guest today is Sarah Lawder. She is Viticulture Extension Specialist and an Assistant Professor in the Department of Horticulture at the University of Georgia. And today we're going to talk about some exciting new advancements around monitoring for powdery mildew and other related topics. Welcome to the podcast, Sarah.

[00:00:16] Sarah Lowder: Thank you very much, Craig. I'm very excited to be here.

[00:00:18] Craig Macmillan: First though, I want to start with something I just found out about that applies to this, and that is the grape frame networks. Can you tell us exactly what that is and kind of how it came about and what it does? Okay. Thanks, Craig.

[00:00:29] Sarah Lowder: Absolutely. Yeah, the FRAME Network is part of a USDA SCRI grant.

This is a project that was funded several years ago, I believe in 2017, as part of the Specialty Crop Research Initiative Project System. And FRAME Networks literally stands for Fungicide Resistance Assessment Mitigation and Extension. networks. And so this was a grant that was really intended to look and learn so much more about how fungicide resistance works in the vineyard for powdery mildew specifically.

But this was a group, a very large group of scientists from all across the country from a wide range of different disciplines looking into how we can better address fungicide resistance for vineyards and for powdery mildew specifically.

[00:01:12] Craig Macmillan: But there's also applications either now or in the future for other fungal diseases like downy mildew, et cetera.

[00:01:18] Sarah Lowder: Absolutely. Yep. They are currently working on getting a new iteration of this grant, Frame 2 as it were that will hopefully be able to address also resistance in Downy Mildew and Botrytis Bunch Rot.

[00:01:29] Craig Macmillan: Fantastic. This is really exciting because what I saw was that there are people at Washington State, Oregon State in California, and then on the East Coast.

So hopefully this work will continue. What exactly kinds of things does Frame do?

[00:01:45] Sarah Lowder: Yeah, so we had a multi pronged approach for this project. One of the big parts that I was a part of is looking at the assessment of the fungicide resistance. So one of the things that we did was collect powdery mildew from all across the country, from states and vineyards all over, all over the place, and then look for different fungicide resistance markers in that mildew.

That can hopefully help us much more quickly assess if we have fungicide resistance present in a sample. One of the big groups of fungicides that we looked at was the QOI fungicides, the Sturbulurins, also sometimes they're called or the FRAC Group 11, with FRAC is the Fungicide Resistance Action Committee.

Is what the FRAC group would be for that and those just kind of group your different fungicides based on the mode of action. So how they work on the different diseases that they're attempting to control. And so we were looking at this group, this group 11, the QOI products which operate by attaching to the mitochondria, so the powerhouse of the cell.

And just preventing them from being able to produce energy and so the, the spores die and you don't get any more growth of that disease. But because it's one of those products that works like a binding site if you get resistance presence it just means that your fungicide can no longer attached to the disease and then it can grow in the presence of that fungicide and then you can even no matter how much you spray that product it can still continue to grow.

By looking at there's one particular mutation that occurs that causes that resistance in this group of products and we're able to run a test much more quickly than you can otherwise do a lot of different fungicide resistance testing And tell whether or not you had QOI resistant or sensitive Mildew in your field so you knew whether or not you could use that product or not

[00:03:35] Craig Macmillan: What about frac group three?

That's another one that we have known Resistance issues with the demethylation inhibitors. Is that part of the project as well?

[00:03:43] Sarah Lowder: Absolutely Absolutely, the DMIs demethylation inhibitors, absolutely, the FRAC3 Group 3 are a group of products that have a little bit more complicated unfortunately of a resistance pattern rather than just having one particular mutation.

There, there are a bunch of different things going on in those products. But we do have a marker that can help us get a sense for the resistance. It's not as necessarily reliable as the QOI. Frack Group 11 product resistant testing, but we can test that as well and give us an idea of whether or not we might have resistance to DMIs present in the field as well.

[00:04:19] Craig Macmillan: Are there other frack groups that have potential or have found some resistant populations coming down the pike?

[00:04:28] Sarah Lowder: Absolutely. Anything that has a very specific mode of action really has some potential for having a resistance develop in a population.

[00:04:36] Craig Macmillan: Great.

[00:04:38] Sarah Lowder: We're, we're looking at some of the modes of action. We have not heard as much of field failures due to resistance to a lot of other products, but we wanted to, like, kind of get a, get a jump on looking for some of those other modes of action to see if we can develop. Test to be able to monitor that, monitor that much more quickly before resistance becomes as much of an issue.

And we were able to get a lot of that information for like the SDHI groups, which is the group 7 products. Although again, we're not really hearing too much yet of any field failures for powdery mildew control from the SDHIs. As well as looking much more into some of the mechanisms for how group 13, quinoxafen how well how the resistance might work in that system.

All of those are stuff that we were able to do because of the Frame Network project team.

[00:05:26] Craig Macmillan: That's really great. I hope that we can continue that. That's really important work. In order to do that kind of thing, you need to get samples. And you and your colleagues are promoting a new method for monitoring for powdery mildew and collecting, I guess, ASCA spores, I would imagine, is what you're collecting.

Tell me about it. There's videos on YouTube. It's really exciting.

[00:05:47] Sarah Lowder: Absolutely.

[00:05:47] Craig Macmillan: It involves a glove.

[00:05:49] Sarah Lowder: Indeed, we call them glove swabs, which is one of the projects that I was able to help lead as a part of the system. Because you hit the nail on the head when you are trying to monitor fungicide resistance.

The first step that you have to do is actually find the mildew. And you want to find this before you have a control problem. You want to find it while there's still not very much mildew present in the field. We looked at, we looked at a bunch of different ways. Not everything worked very well. But one of the ideas that we had was, oh, We have vineyard workers moving throughout the field all the time.

Could we potentially use these people who are already in the field doing normal stuff to also potentially collect powdery mildew? And we found that as you're moving through the vineyard, as you're moving your hands along the canopy, you're able to collect powdery mildew. Conidia spores, actually, it's generally, it's their summer spores.

are collecting and you're able to take a, just a cotton swab. So many of us have taken a COVID test that you've had to stick up your nose. It's a very similar, similar swab that you take with your hands. And you can stick that in a tube and send it to the lab for processing. This system worked, I think, way better than any of us were expecting it to.

It was actually much better than trying to go out there and look for it physically. And you can do it much faster because it's just literally, you can be walking through the vineyard with your hands in the canopy, take a swab. and collect it, and you can find that so much faster if you're already having to do a lab test for that product.

[00:07:16] Craig Macmillan: And also the potential here is that, let's say I've got a crew out and we're doing a shoot thinning in the spring, so they're handling the canopy all the time, we could swab some gloves and then send that out to be tested and get an idea what's out there.

[00:07:27] Sarah Lowder: Absolutely. Absolutely. And as you're already testing for whether the field is out there, you can also use the same test to tell whether or not you have resistant mildew to the QI fungicides.

[00:07:38] Craig Macmillan: Is this quantitative?

[00:07:41] Sarah Lowder: So, it is run on a quantitative quantitative PCR. So, in theory, it does give you some information on how much mildew is present. In the QI QPCR test, in the test that tests for the fungicide resistance pattern, it tests a piece of DNA in the mitochondria, and you can technically have different numbers of things.

Mitochondria per cell, individual cell, and so the, the quantitative, it does give you that information, but it's not necessarily the most reliable information. So as, as a scientist, I'm always hesitant to say that, oh, you can get quantitative information, but it, in theory, it does give you a little bit of information about how many spores at least you were able to collect.

You can tell a little bit of that information.

[00:08:21] Craig Macmillan: Can it tell me something along the lines of, I can go out and sample at the very beginning of the season, maybe even post bud break, and say, oh, we have nothing there yet, and then come by later and test and say, oh, we have something there now. Is there a qualitative aspect to it?

[00:08:41] Sarah Lowder: Absolutely. So we tested it and compared the glove swabs to visual scouting to compare it to someone actually physically going out and looking and found that the glove swabs were much more sensitive. They were able to find the powdered mildew much faster, and also much sooner than the OR than our visual eyes were able to do So.

But we also tested it in comparison to impaction spore traps. So these are tests that actually had come out of a lot of the lab that I worked in the foliar pathology lab with Walt Mahaffey at the USDA for a couple years previously with like Lindsay Thiessen that they were able to test these impaction spore traps which sample the air that flows through the vineyard.

We're collecting that many of the vineyards in the Willamette Valley of Oregon which we did a lot of the testing in that area as well as in Areas like Napa, California have a bunch of these spore traps present that we were able to test it in comparison to these spore traps, which have been used pretty widely in the system.

And what we found was that our glove swabs were showing us very similar information to these impaction spore traps which was really cool because a lot of these growers absolutely do use already these impaction spore traps to look at when they're going to initiate their fungicide spray programs.

So, in theory, yes. You could absolutely potentially use these glove swabs as a fungicide initiation indicator.

[00:10:01] Craig Macmillan: Yeah, that's what I was getting at, and that's, that's a really exciting technology. Because obviously we're trying to control the amount of material we put out there, and obviously part of resistance management is being careful what you put out and when.

And so having a good idea of what the timing should be, I think, is really important. And then of course, as everybody knows, People who listen to this podcast know, by the time you see it, it's too late, baby.

[00:10:24] Sarah Lowder: Absolutely.

[00:10:24] Craig Macmillan: You know, it's, it's, it's, you're chasing a ghost. And so, here's, here's our Ghostbuster tool, where we can catch that ghost before before it comes too much of a problem.

Now you said, send these off for, to a lab for analysis. What what labs are we talking about?

[00:10:39] Sarah Lowder: The initial frame grant project is technically at a, has come to an end and so the funding that originally funded a lot of this testing has ended, but now we're able to supply all of these protocols and testing materials and stuff to a lot of the different private labs elsewhere.

So I know one of the private labs that does the impaction trap testing. service in the William Valley of Oregon has taken over that process, as well as I know a bunch of different labs like I know at UGA here, where I am currently, they have some tools and able to do some of those testings or do some of those tests as well with the qPCR.

And so even if you, a lab where you send a lot of your materials, if they happen to have a qPCR present and you're strongly interested in doing it, you can talk to them to see if they might potentially be willing to add this into their repertoire.

[00:11:24] Craig Macmillan: So, this technology is starting to make it out into the world of commercial plant pathology.

[00:11:29] Sarah Lowder: Yes.

[00:11:30] Craig Macmillan: I may have a plant pathology lab that I already work with, I can talk to them, I can make some phone calls, and for instance, a commercial lab in Oregon, they're a business, so they still may do samples from California or from Washington or from Ohio.

[00:11:44] Sarah Lowder: Yeah, potentially.

[00:11:45] Craig Macmillan: It's not limited by territory.

[00:11:46] Sarah Lowder: Correct. You can send these samples and as long as you're not leaving your samples out in the sun and in the heat for a long period of time they can be shipped off elsewhere as well.

[00:11:55] Craig Macmillan: Where do you see this technology going? What's, what's the future here? We, we, we've just kind of touched on it a little bit, but what, in your, when you close your eyes and imagine the long term impact of your work, where do you see this kind of thing going?

[00:12:08] Sarah Lowder: One, I would love to see a lot of this information being used more regularly to be able to test this a little faster. And eventually, one day, we may be able to test for all of these different resistance genes, all of these different resistance patterns within the same sample. So you could be like, okay as a normal part of my practice, I'm going out and taking these glove swabs or whatever else that I'm looking to test.

Even if I don't use a glove swab, but I can come in and take my powdery mildew sample and send it off to the lab and get a, just a score sheet of exactly what fungicide products could be used or could be not used. That would be really awesome, because no one wants to buy a product that it's not going to work, and no one wants to put a product out that's not going to work for any reasons, environmentally or financially.

In the wallet or just for labor purposes. It's just a win, win, win situation. If you know, you don't have to use a product and instead you could choose a different one.

[00:13:01] Craig Macmillan: Oh, this might be a related, very practical matter. So gloves, touching vines, no problem. I can have workers. I could have actually my VIT tech go down a row and then swipe the canopy.

Where do I get the swabs because we're talking about something has to be a sterile protected swab, just like the COVID test swab. Where do I get those?

[00:13:17] Sarah Lowder: Yeah so a lot of the times, or at least for a lot of this test that we did originally they were groups that we sent out, or like just kits that we would send out to the different cooperating practices.

But essentially, it is literally the same tool. It's a polystyrene cotton swab tip and we normally will put them into these little half tubes that kind of keep their tip protected, and then you will stick it back into the plastic wrap that it came in, and then wrap it up so that it stays more protected. But it is, it is literally the same tool that you often will use for those COVID tests, which made it really hard to get that right at the beginning of the pandemic.

[00:13:54] Craig Macmillan: Where, where can I get them? Where can I order them from?

[00:13:56] Sarah Lowder: So I can send a link for the type of material that we're looking for. And then you can shop around for the same tip at a couple different locations and find the best price.

[00:14:06] Craig Macmillan: That'd be perfect. We'll put a link to that in the show notes. So folks, you can go check that out and find the materials that you need.

And then you can also shop around for the labs and see who's doing what. And again, if a lab is getting a lot of phone calls. That's going to encourage them to adopt this new technology. What is kind of the, the current state of the nation, if you will, in terms of fungicide resistance, what are the hot new topics, what's getting funded?

What are people working on and where are they working on it?

[00:14:33] Sarah Lowder: Fungicide resistance is certainly a hot topic that has a lot of different research happening in a lot of different areas. I could literally fill your entire podcast probably with talking about this topic. One thing that I'm very excited about is to hopefully see this Frame 2 iteration happen that is, being submitted for funding for this next funding cycle this year, but it is looking to hopefully also add in testing for downy mildew and betritis bunch rot, which are also two big diseases that can cause a lot of issues.

Especially now that I'm over here in Georgia, I'm very excited to hopefully get to test much more of the downy mildew which can be quite the struggle in the vineyard. And we're getting much more information on a lot of the other modes of action that we're working with. I'm excited to see a lot of the information come out about some of the quinoxephins.

Some of this information that we have started to work on and we haven't seen much field resistance to these products yet. But if we continue to use them, then they may still pop up. And so hopefully making sure that we can get ahead of the game for these other products.

[00:15:37] Craig Macmillan: I'm very happy about that because I'm old enough to remember when the DMIs came out and it was like, Oh my god, it's a secret.

It's the silver bullet. We're never gonna have to use sulfur again. Yay, and then it was literally within a couple of years they failed in some places. Now, the Fungicide Resistance Action Committee is publishing better information, more information, more accessible information every year about what's new about the different code groups.

And they're also now putting a category in, or they have for a long time, but they have a category in there about the potential for resistance. So they'll say, yeah, there's known resistant populations for this. This one has got high potential, even if we haven't found it yet. And that's directing research in that direction.

And I think that's really important that we stay ahead of these things. things, looking at where the potential is, as well as where there's known issues. So that's really fantastic. This is going on at what OSU, MSU, I think, Tim Miles in Michigan Walt Mahaffey in Oregon. I think Washington state.

[00:16:35] Sarah Lowder: Mm hmm. Michelle Moyer is the viticulture specialist at Washington state university, who's been the project director for this project, led with Walt Mahaffey, who is the foliar plant pathologist at the USDA located in Corvallis. the horticultural crops units. And then a whole, a whole group of scientists from across the nation.

There are people at UC Davis. There's people at Michigan State University. Even while I worked on this project in my role at Oregon State, I'm at with the USDA in Corvallis, Oregon. I'm now here at the University of Georgia working with Phil Brannon, who was the University of Georgia, Scientist working on this project and who actually was the person that convinced me to actually apply for the job that I currently now sit in.

[00:17:20] Craig Macmillan: That's great. You know, we do still have a little bit of time left. This is a huge topic, but I found it interesting as I was doing research on you and looking at your publications. One of the things you've been involved in is research on collective action. and information transfer among growers related to disease management.

And I am really fascinated by this topic. My background is in sociology. So my background is in people, talking to people, doing people stuff. And as we know, things, not just diseases, but also insects like mealybugs, etc. It's an area wide issue. And what you do or do not do on one farm affects what happens or doesn't happen on another farm.

Can you tell us just a little bit about what that research was like, what you did?

[00:17:57] Sarah Lowder: Absolutely. So that was really coming from how do we branch out from some of the fungicide resistance? Like how do we use a lot of this information that we are getting? One of the things that we were realizing is that some of the vineyards that we were working with, that we were getting some of these tests from, even organic vineyards who were not using any, they weren't using the QIs.

They also weren't using any other synthetic product. We're still seeing sometimes very high rates. of the fungicide resistance to these different products. And what we really found was that a lot of the information that we were able to look at was really so much more useful on that larger scale when we were able to look at all of this data in the aggregate.

And so one of the things, which I'm going to talk about my experience with the Oregon State, in the William Valley Vineyard growers especially, that they took all of this information, that they took the data, powdery mildew information that we are getting from their impaction spore traps. They were taking the fungicide resistance data that we were giving them, and they were sharing all this information with each other.

And we're able to say, Hey, oh, I was using this product, you know, on my field this year and next year. And then I started to see a lot of issues. You didn't see it immediately, but you saw it pretty closely after I did, even though you followed the patterns elsewhere. And so they were able to take a lot of that information and aggregate it and share together and be able to use that much more quickly.

I didn't talk too much about how much of the fungicide resistance that we were seeing. We definitely did see some differences in some of the states. that we were looking at, although it was generally pretty high rates of resistance to the QI products across the nation. That degree was less in a lot of the places in Oregon where a lot of this information started and where they shared a lot of this information from the get go.

So one of the things that we wanted to look at was how does this information come across and then what do people do with that information? Absolutely. So when you get into the area wide management, when you, when you start talking about it, you're like, okay, while I manage my property, Unfortunately, a lot of these diseases aren't just staying on my property.

If we could, if we could keep everyone isolated, then we wouldn't have to talk about a lot of this information management information management across all these different regions. What do we do once we have that knowledge and once we're sharing all of these spores back and forth even if we don't necessarily want to share that.

But if we can also share some of the information on what we're all seeing, we can all manage it a little better. Even if it's just as simple as like, Oh, my sprayer was not calibrated correctly and I'm starting to see More powdery mildew in my vineyard blocks. If you communicate that to your neighbor, then they may be able to increase their spray intervals a little bit more in order to not lose their crop because they're going to have to deal with a much higher crop load.

And they could be looking at the spore information. They could be looking at any of these monitoring effects that they're collecting. But if you can know that a source population nearby is going to be pushing more spores more readily, that's even before it's hitting your vineyard. So it's getting that information even a little faster than you would with some of the spore monitoring efforts, if that makes sense.

[00:21:01] Craig Macmillan: That does make sense. And so, in terms of the collecting the information, this doesn't just have to be glove swabs or, you know, impaction traps. This simply can be people saying, hey, I'm seeing mildew pressure that's pretty intense, or I'm seeing it earlier, or whatever. Other people are saying, I'm not seeing it yet, but I know I'm downwind of you, for instance.

Or, I know that my conditions are still very conducive, so I might be able to, like you said, increase my spray intervals, maybe check my calibration, check my coverage. It's a, it's a heads up. Basically from from one grower to another. How is this information shared?

[00:21:34] Sarah Lowder: So there are lots of different ways that this information is shared One of the ways that we wanted to look is at just what did people find the most useful when they were Looking for different information on either new diseases or old diseases or all that kind of thing And some of the stuff that we were finding was that people really found their colleagues, just those person to person conversations that they were having to be the most useful information when managing any diseases.

And while people certainly found, which I was happy to hear, that people found their viticulture specialists, their extension agents, to be extremely useful when helping to find this information, they really were still, the the most important part was their colleagues and their neighbors, the other growers in the area.

And so you can look at different ways that people communicate, which we, one of the things that we did was look at a communication network. So just exactly how is that information flowing in the system? And there are certain people, which this may not necessarily be a huge surprise. But there are certain people that a lot of people go to, to learn more information about stuff, especially as someone that is looking at a region and be like, Ooh, I have one, this super great new tool, mate, I have something even cooler than the glove swabs.

And now I need to tell. the growers about it. I need to see if we can actually use this in a commercial way that'll be viable. You can go to some of these more influential individuals within a region and then hopefully see that information spread a little bit more quickly than it might otherwise if you just kind of picked your people based on just where they were located or even just the closest ones you get your hands on.

As it were.

[00:23:09] Craig Macmillan: Gotta find the node. Gotta find the hub,

[00:23:11] Sarah Lowder: find the node. .

[00:23:14] Craig Macmillan: This is an interesting topic to me because one of the things that I think we've lost from a cultural standpoint is the coffee shop. People who are now retired growers have talked to me about how you're on your farm. You know, before sunup you get things running, you get going.

People are doing what they're doing. Everything's fine. And then you go to the coffee shop about nine o'clock and everybody's there. And that's where the information would get transferred. And this goes back to the, you know, basic farming decades ago. We don't do that anymore. What we do is we're there at Sunup before Sunup, we get things running, we get done, then we're back in the truck and we're on the phone and we're going to the next ranch and we're not connecting with people.

In that kind of social conversational way, the way that we used to. And so hopefully we can revive some of that either through meetings or through internet or through just simply networks, like you said, if there's a relationship, you can just simply call somebody and say, Hey, I'm starting to see this and hopefully we can build those social networks and see the collective benefits

[00:24:12] Sarah Lowder: and find more ways to bring us together.

[00:24:15] Craig Macmillan: Find more ways to bring us together in a world that seems to be forcing us apart, right? No. On this topic of managing diseases and monitoring diseases, is there one thing you'd recommend to our listeners around this?

[00:24:27] Sarah Lowder: There are lots of different diseases in lots of different ways that a lot of things are managed and we talked a little bit about Collective action in the sense that a lot of times some diseases are more effectively managed on a much wider scale than an individual Farming unit so like you could do the best practices in your own vineyard but if you have Someone next door doing lawn best practices that could just mitigate all of the hard work that you just put into it.

But it's hard to say anything on the large scale other than the fact that Talking more with those around you has a much wider benefit for disease management on all scales And just also grow better cultural practices, better more information on learning. I may be someone in the academia realm, but I always think that the more you can learn, the better.

And your neighbors are in the same game as you are, especially in vineyards. I feel like the mantra of the rising tide lifts all boats is very much in effect.

[00:25:24] Craig Macmillan: So we can learn from extension and from all that great stuff that's out there, but we can also learn from each other. Sarah, where can people find out more about you and your work?

[00:25:31] Sarah Lowder: Yeah, so now that I'm over here at the University of Georgia, where I'm most easy to find is through the Viticulture Extension website. It's called the UGA Viticulture Blog. We post a lot of information relevant to those growers in the southeast, but we also have a blog posting that sometimes will go out via email if you would like to sign up for that, backlog of what we've posted.

It's the easiest way to find me. I'm all around the University of Georgia system.

[00:26:00] Craig Macmillan: Fantastic. Thank you so much. Our guest today was Sarah Lowdre. She's a Denture and Viticulture Specialist and Assistant Professor in the Department of Horticulture at the University of Georgia. Thanks for being here. This was a great conversation.

[00:26:10] Sarah Lowder: Thank you, Greg. I had a great time.

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