Sprayable Pheromone Mating Disruption 101

On this episode of Suterra's Trap Talk podcast, Karli Petrovik interviews Dr. Emily Symmes, a PhD in Entomology from the University of California and Davis, about the benefits of sprayable mating disruption.

Listen to the podcast here, or read through the attached transcript below.

Transcript

Karli Petrovik 0:06 

Hello and welcome to the Suterra trap talk podcast. As the global leader in sustainable pest control, Suterra works tirelessly to deliver quality products customers can trust. Ones that boasts consistent chemistries, and the most reliable hardware on the market. My name is Karli Petrovik, and I'll be your host for today's episode of the Trap Talk podcast. Joining me is Dr. Emily Symmes, a Northern California native who discovered a passion for Applied Entomology and Integrated Pest Management as a teenager, eventually earning her Bs, MS and PhD degrees in Entomology from the University of California in Riverside and Davis. Prior to joining Suterra, Dr. Symmes served as the UC Cooperative Extension Area IPM advisor in the Sacramento Valley, and as Associate Director of Agriculture for the Statewide IPM program, working alongside growers, PCAs, and others in the orchard industry to address pest management issues, and share advancements. Today, Dr. Symmes joins us to discuss everything growers need to know about sprayable pheromone mating disruption in order to effectively address their biggest pest problems. Tell me a little bit about your background in this field and how you began working with Suterra. 

Dr. Emily Symmes 1:25 

I've been working in California agriculture for going on 30 years, I always kind of have to go back and realize that it really has been that long. So I've been working in Cal Ag for almost, you know, 35 years. I started working for an independent PCA consulting firm as a teenager, I answered the phones and routed things through the CB radio. So that gives you an idea of how long ago that was, with building, you know, monitoring traps in the office. And then they took me out in the field. And I started learning how to scout and look for different things and help with you know, small scale experiments and, and all of that. And from there, I was really encouraged by the owner of that firm to go on and get my education. So from there, I went on and I pursued a bachelor's and then a master's and then a PhD in entomology through the University of California system in Riverside and in Davis. Throughout that entire time, my focus was really on Applied Integrated Pest Management, Applied entomology with a focus on Agricultural Entomology. So always, you know how to help the ag community how to help growers, always with that very kind of end user approach in mind. From there, I went into the UC Cooperative Extension System for several years where I was an area Integrated Pest Management advisor within the UCC system, and Associate Director of Ag for the UC statewide IPM program that's based out of Davis and kind of generates a lot of that, that kind of flagship web based IPM content for the state. From there, I was contacted by Suterra to join their technical field team. And it really was an opportunity to bring me back into the world of pheromones, the world of mating disruption, and really dive deeper back into those types of things. And really get to again kind of work in a way that really helps growers at the end of the day bringing solutions to the field. So my current position is as the Senior Manager of Technical Field Services with Suterra, which is you know, as one of the global leaders in sustainable pest management and pheromone based solutions, both mating disruptants and monitoring tools and some other types of kind of low impact products on a global scale. 

Karli Petrovik 3:48 

Okay, so what is sprayable mating disruption? 

Dr. Emily Symmes 3:52 

So sprayable mating disruption products are what are called micro encapsulated formulations. In a capsule suspension, that's kind of some of the pesticide formulation terminology that goes around that. So they're designed to be sprayed on like a conventional agrochemical, like an insecticide. But with that very unique different mode of action of mating disruption that we're used to with, like the puffers or aerosols, or some of the hand applied dispensers. And so I kind of think about it as this this sort of hybrid, right? It's not a pesticide it doesn't kill, it still has that unique mode of action, but it's packaged and applied in a way that's very familiar to egg in terms of it's sprayed-on like many of our other agrichemicals are. We call these these microencapsulated formulation micro caps. And we can think of these micro caps as billions and billions of teeny tiny little pheromone dispensers out in the orchard. And what's really unique about this and what what Suterra's team of engineers has been able to do is provide this engineering around that pheromone active ingredient with that micro cap so that it is both at the same time protected from those real world elements, but in a way that it's able to slowly and continuously release that pheromone active ingredient inside into the environment. It really is kind of a chemical engineering marvel in terms of like advancements within the mating disruption field. These micro caps have to be robust, you know, withstand the elements, but then, again, allow that pheromone into the environment. 

Karli Petrovik 5:37 

So how can sprayable meeting disruption be used to reduce or eliminate pest problems? Basically, tell us how it works. 

Dr. Emily Symmes 5:45 

Right? Right. So like any meeting disruptant, whatever the platform is, sprayable formulations function by inhibiting the ability of mates to locate one another, successfully mate, and ultimately produce viable offspring or offspring that are capable- basically viable eggs that are capable of turning into a live larva or a live nymph at the end of the day. For many of the agricultural pests that we have products for, and for a lot of the key agricultural pests, it's the female that produces and emits the pheromone. And it's the male that cues in on that and responds and then flies to the female. So when we add mating disruption pheromones into the environment, for example, with sprayable micro caps, what we're doing is inhibiting the ability of the male to locate that female. Basically, this is just kind of how the disruption ultimately works to reduce the populations as it can completely block the male ability from ever finding a female throughout the entire duration of both of their lifespans. He searches forever, they don't live that long as adults, he dies. She sits there calling forever waiting for a mate to find her. He never does, she dies. But the other mechanism at play is that it can delay his ability to find her so he's confused, but he eventually finds her. With these females, they're quite short lived, but each successive day that she lives for her egg resource becomes less and less viable. So if she doesn't get mated until day two, three four or five, the total number of those viable eggs that she'll lay drops down dramatically. And so it's kind of these combinations of these two, you know, you block it completely or you delay it significantly. What we see is that results in significant decreases generation after generation, each population becoming much, much smaller than the generation before, or what this leads to, obviously, lower population, reduce crop damage efficacy of the product. And we'll talk a little bit about how that smaller population size actually allows all of your other pest management inputs to be that much more effective as well. 

Karli Petrovik 7:59 

So now does this work with any pest or what pests are kind of great candidates for sprayable mating disruption? 

Dr. Emily Symmes 8:06 

`So um, there's a number of species for which sprayable mating disruption is available depending on the system and where you are in the world, and the impact of that species. The very first was actually for pink bollworm. That was the very first sprayable and that's decades ago now. So this is not like a brand new novel release platform for mating disruptant. Some of the key primaries for which we have sprayable mating disruption formulations are Navel Orangeworm; that's primarily a nut crop pest. Even though it says navel orangeworm, it's really not a citrus test. It's, you know, almonds, pistachios, walnuts. Vine mealybug, which is a grape pest. Codling moth, which can be a pest in Californian walnuts, big pest in pome fruit, Pacific Northwest and globally. Diamondback moth, which is a very very critical issue in cole crops and is highly resistant to a lot of the traditional insecticide chemistries. Oriental Fruit Moth, Peach Twig Borer, Beet Armyworm, Tomato Pinworm, False Codling Moth, we have lots of different sprayable options. And for a wealth of other species, we've got some of those other platforms as well. So we've got aerosols for many of these, hand-applied dispensers for many of these, and lots of others. What makes a particular pest a great candidate for a sprayable mating disruption? There's something to do a little with the ecology of the pest, but really, it's just a matter of providing growers different options of platforms. Like we love the idea that we can provide a sprayable option or an aerosol option or in some cases a sprayable and an aerosol and a dispenser, what-have-you, so that growers have that flexibility to choose what matches best with their operation. 

Karli Petrovik 10:01 

Okay, great! So this wasn't a question I necessarily had prior to that last response. But how would one decide what is the best kind of delivery method for their operation? What factors kind of go into that? 

Dr. Emily Symmes 10:16 

So, you know, availability of which platform, a number of factors. So, you know, when we think about like an aerosol or like a hand-applied dispenser, we typically think of those as you make that decision early in the season, and you're going to get season-long, and it's a certain investment, and you kind of make that decision early in the season. You also have some additional labor inputs that go into hanging those, and they're potentially not as familiar as the 'Hey, put it in a tank and go out' that a grower might be used to. So it's really just a matter of a lot of different things. With the sprayable formulation, I really like it because one, it's familiar, right? How I apply it is familiar. Two, it allows you that flexibility to maybe not have that upfront investment in the season and be able to pivot and respond to in-season conditions. It allows you to maybe more economically get mating disruption into your orchard, right, if you're not doing season long, you're doing a couple of sprayables, you can target one particular time of a certain flight, or phenology of the pest, or a couple of particular times through the season, or where there's peak crop vulnerability. So it allows this flexibility, affordability, sort of that precision approach. 'Hey, I might not need full blown season long meeting disruption everywhere, this block. Hey, maybe just a spray to different timings,' or something like that. So that kind of precision approach to meeting disruption. And especially when we're in seasons where crop prices are not as high as they can be and growers necessarily have to think about input costs, and cutting costs and things like that, you know, mating disruptions still serves a big value in helping suppress populations and drive those numbers down. But it's understandable if 'Hey I don't know if I want to commit, I don't know what the population is going to do this year, I don't quite know what the prices are going to be...' It allows for them to pivot in season. And I think that's one of the big, big benefits there. 

Karli Petrovik 12:26 

Great. Yeah, that makes a lot of sense. So now, what if an operation is using beneficial insects? How does sprayable mating disruption work with those other things that growers might do to limit pest populations? 

Dr. Emily Symmes 12:42 

Yeah, so I like to kind of first couch it. I think sometimes people think that operations using beneficial insects necessarily means purchasing and releasing beneficials. And that's certainly the case in some of our systems. But others, a lot of times rely on what we call conservation biological control. So you're not buying any additional inputs, you're not releasing any additional natural enemies. You're merely developing your IPM program to conserve and enhance what's already there working for you, right, a little bit of that cheap, free labor sort of thing. So that said, this applies to either case, right? Obviously, if you're buying and releasing, you want to protect those, so you don't want to buy a release, and then come in with an insecticide right away and knock them out. But at the same time, even if you're just conserving, you want to have pest mitigation approaches that allow you to conserve and enhance and so with that mating disruption, sprayable, or any platform are highly specific to the target pest. So it uses the pheromone chemistry of that target pest. So it's not going to have a detrimental impact, like a toxicity level detrimental impact on your biological control agents, your natural enemies, your predators, your parasitoids. No direct harm there, nor does it harm other beneficials like your pollinators that we all want to protect in the environment. So that high species specificity means that we're really just targeting that pest for which that mating disrupted was developed. I actually consider mating disruption and biological control, highly complimentary, right? Because they're targeting different vulnerabilities in the past life cycle. Mating disruption's targeting that that mating mate location aspect. Biological control is targeting another life stage, whether it's an egg parasitoid or a general predator that eats the larvae. So we're we're coming at it from multiple directions, which is the exact idea of a good IPM program, right? And so not only do they not harm each other, but they're actually really, really mutually beneficial. It is important though, when we think about sprayable mating disruption is that they can be tank mixed with other types of agrochemicals. So if you're tank mixing with something that is more like an insecticide, you'll want to be pretty careful about timing that and knowing how that particular insecticide mixes with the pheromone, if that's what you're doing, how those might impact your natural enemies. 

Karli Petrovik 15:12 

Okay, good information there for sure. So now that with all your experience, kind of in the field, and in this field in general, what impacts have you seen sprayable mating disruption have on pest populations? Can you give some examples? 

Dr. Emily Symmes 15:28 

Um, yeah, so I think I mentioned, you know, in terms of, you know, how these work for farmers and how they impact the pest populations, it's very quite easy to sort of model what disruption does, right? In terms of, you know, at various levels of starting populations, the efficacy drives each generation down, and you have models where you actually get negative population growth. And that's the ultimate goal, right? In terms of how they work for farmers, like I said, some of the key features is that affordability and flexibility and use pattern. So how farmers can incorporate them into their overall program and operations is one of the key features and there's no shortage of variable kind of use patterns and how folks are using them effectively. I like this ability to tailor a sprayable type of disruption to, again, your operational schedule, your pest cycle that you're watching closely, your pest pressure that you're watching closely, and then ultimately into your overall IPM goals, right? We often get questions of 'Is mating disruption an additive? Am I adding it to my existing program and keeping everything else the same? Can it be used as a substitution for one of my other inputs?' And the answer to that is it depends, right? It depends on where you are right now. And it depends on the goals of your program. And that's really where a lot of this flexibility lies. Again, kind of how it works for farmers, like I said, it's a familiar technology, so to speak. So they're able to spray it with their conventional equipment, nothing new or different needed. So they can use a traditional airblast type sprayer, they can go on aerially. We've had some folks experimenting with drone applications as well, as those start to get a little bit more popular. But largely, we've seen California growers in particular and I live in California. So I'll say globally, this is widely used, but specifically, California growers have used our sprayable formulations with a lot of success both in population reduction, damage reduction, return on investment, particularly in the grape system for vine mealybug, the almond system for NOW, some pistachio (a lot of pistachio tends to use the season long puffer technology), cole crops for Diamondback moth. We've seen a lot of grower success with incorporating into those systems. 

Karli Petrovik 18:04 

Great. So now, why is this particular form of pest management important for growers to use on their operations? Even if they're doing some other things? 

Dr. Emily Symmes 18:16 

Yeah, you know, this always gets into the not fun part of the conversation where you really kind of think about what's the future of agricultural and pest management and what are growers faced with. And I think that we all kind of in the industry know that growers and operations managers, and crop consultants are all really aware of the challenges facing Ag. You know, when we think about increased regulation that may be limiting our pesticide options, to increasing pest pressure that we're seeing, you know, with some of these really mild winters and warmer summers. All of this means that we really have to have fully realized IPM programs in place. And I think everyone knows that that's becoming more and more critical as we're thinking toward the future. Really to be successful in managing our most destructive pests, we know that we have to kind of bring everything to the table. So whether it's our cultural controls, and our chemical controls, and exploiting biological control as much as you can, and using things like behavioral modulators, like mating disruption, they're all going to have to have a place. We've really got to keep pest populations quite low. Some of these key pests have very, very low tolerance levels, whether it's because, you know, Navel Orangeworm, for example, gets into the harvestable nut kernel and can actually bring in some toxicants with it. Or vine mealybug which is not just a direct pest but also vectors a virus that can ultimately kill vines. We know that we need a lot of inputs in a lot of cases, but we have to be really, really careful to mitigate insecticide resistance development to comply with those regulatory issues and really ensure the long term sustainability of the program. So what we're talking about is, you know, we're not talking about going totally away from insecticides. They have their place. They, again, target a certain aspect of vulnerability. But what we do by incorporating the mating disruption and the cultural and the biological is extend the lifespan of those kind of important chemical tools as well within the bigger picture so that growers can continue to be successful going into the future. I think, you know, some of the other considerations are that, for growers, there's flexibility in these non toxic approaches like a mating disruption, right? We don't have to worry about MRLs, or those negative residue levels there. Because they're so low toxicity or non toxic, we can often protect the crop right up until the day of harvest without worrying about MRLs. Typically, there's very, very little what we call reentry interval with with a sprayable formulation meaning your crew can get right back to work in the field after an application. The reentry intervals are four hours for a sprayable and zero for any of the other platforms. And I think all of these are things that growers know they need to be considering. And then some of the added value that that something like a mating disruption can bring especially late in the season close to harvest. 

Karli Petrovik 21:23 

Okay, great. So you touched on this a little bit, but how is sprayable mating disruption used in conjunction with these other tools? What might it look like for a grower who is already using some pesticides, using some biological approaches? How do those all work together? 

Dr. Emily Symmes 21:40 

So I think and I mentioned the complimentary nature with bio control, but really mating disruption, because it's got its unique place, it's complimentary with everything. And again, if you look at that kind of population model approach to effective disruption drives numbers down. So that means 'Hey, if I've got to come in with an insecticide, at time A or B, or C, and it's going to kill 50% of the population with a great application, I'm killing 50% of a much smaller population already.' So my ROI on my chemical just went way up. You know, same thing, if you're thinking biological control, you know, if I'm going to release, or conserve, we've got a better ratio, potentially, of natural enemies to the bad guys, which can help further balance. So I think, you know, complimentary, absolutely. And really, also the idea that when you reduce that population, everything else you're doing is just almost amplified in terms of its efficacy. 

Karli Petrovik 22:40 

Okay, and how about some of the common misconceptions you encounter about sprayable mating disruption? 

Dr. Emily Symmes 22:47 

So with regard to sprayable, specifically, I think the folks don't actually really know how affordable it can be. I think that they think mating disruption, that's a capital investment, that's a big investment, right? But if we think about the application costs per acre for sprayable mating disruption, they're actually less now than many of our more commonly used selective insecticide products as we're going into these more softer, newer generations, quote, 'more selective insecticide chemistries', those are getting out of the realm of the cheap sort of spray. And so we're actually right in line or quite a bit lower than those types of investments. So that's, I think, one misconception. The other is how long they last and we do get much, much longer, we'll call 'residual activity' or 'action' out of our sprayable microencapsulated formulations, which are designed to be slow release, than we get out of a lot of our more conventional insecticides. The other thing that's really important to remember is it's hard because it's like, I'm spraying most everything I spray kills, and it's like, okay, no, we got to remember that this spray doesn't actually kill anything. It's doing its disruption by releasing from those micro caps. So with that, we don't have to have that thorough coverage, that most of insecticide chemistries require, where you've got to get really thorough coverage of the plant material typically, for maximum efficacy. With the micro caps, we need a uniform distribution, but because they don't have to come in contact, they just have to be in the environment to emit the pheromone. We don't need that type of coverage. So it's important to remember it's sprayed on like an insecticide, but the mode of action is quite different. So I think those are a couple of the most common things to continue to remind folks about. 

Karli Petrovik 24:47 

Alright, so now let's talk about how sprayable mating disruption is changing the conversation around pest management and sustainability. How is this mode of action changing the game? 

Dr. Emily Symmes 25:00 

Well, you know, within mating disruption, it's an option, right? It's a new option. And even though we've had sprayable formulations around for a long time, I think that the aerosols, the puffers, these other kinds of approaches have gotten a lot of the attention. But again, I think how it's changing the conversation is that growers deserve options. They really deserve options for incorporating mating disruption in a manner that's comfortable to them, that's affordable to them, that makes sense to their operation. And so what the sprayable products offer are just that additional choice of 'Hey, you know, I'm not a puffer user, that doesn't fit my program, or my operations or my mentality, or you know, dispensers don't fit my operations.' So, we think of, again, I kind of mentioned this earlier, we think of what we call the season long, the aerosols or the hand-applied dispensers. We typically make that decision quite early in the season, we know we're going to make that investment. And in many cases, we make that investment because it makes sense. Obviously, if you feel that season long approach makes the most sense to your operation, and it totally pays for itself. You know, that's a great option. But the sprayable is, I think, can be used with that more reactive in season precision approach, 'Hey, I'm just going to target this part of the flight, or this particular flight or, or, you know, hull split through harvest or, you know, get out there where there's a lot of insect activity happening really late in the season where I can't spray something else because of residue issues.' So I think that's the game changer is that flexibility in the idea that we can be reactive and kind of site specific and precision with mating disruption, as opposed to sort of always just that season long approach. 

Karli Petrovik 26:48 

And it is a sustainable option, correct? Because of its low toxicity? 

Dr. Emily Symmes 26:53 

Absolutely. I mean, all of the kind of features, advantages, benefits of these other types of platforms are completely the same with our Flowable option or sprayable formulation options. You know, yeah, that low toxicity, superior safety profile, very species specific, you know, non toxic, no environmental considerations kind of thing. 

Karli Petrovik 27:19 

Okay, and then Emily, anything you think I missed that's important for growers to know about this option? 

Dr. Emily Symmes 27:23 

Specifically with sprayable pheromones? Not necessarily; more of a few general comments about your overall IPM program. I think growers are necessarily, you know, 'What's the ROI? Is this paying for itself? Am I getting bang for my buck?' And obviously, there's always the dollars and cents. When we talk mating disruption, we talked about the intangibles a little bit, right, that more long term sustainability, all of those other kinds of things with regard to preserving beneficials, the environment, all of that, but I just really always try to encourage folks to continuously evaluate that overall IPM program. So what were the inputs that were used? How do those contribute to your damage reductions or your quality preservation or enhancement? Look at that IPM program pretty holistically in an ongoing way. It's pretty hard to tease apart individual inputs. Most of the pests for which we've developed mating disruption are pests for which we have to attack them from multiple ways. So it's not always easy to say 'Okay, my program involves both cultural methods and biological control and disruption and some insecticides. And I got to this number, so which one paid for itself?' So we have to be a bit holistic when we're looking at that. But I encourage this so that they can kind of continue to evolve their program on an ongoing basis. And to me, it's a learning feedback loop. And the folks that do this for a living, growers and their consultants, they absolutely really know this. I think that it's important with that long term IPM approach that incorporates meeting disruption, or these other types of population reduction over time, that we don't just look at a single year snapshot, either in terms of our evaluation. We have to think about a multi year approach to evaluation. Obviously, at the end of the day, that damage data, you know, where did we end up on a grading sheet or yield or whatever, that's the holy grail, right? That's really going to be the proof in the pudding of how did our program do. Where were the hits, what were the misses, what are the refinements that we need to have going forward? You know, I had a couple of comments and I don't know that they'll fit within this cut and paste, but oftentimes, we also use some various monitoring tools to evaluate how well disruption is working or at least have a validation or verification that the mating disruptions are active in the field. We've seen that with the increased adoption of mating disruption, we've had new monitoring tools come to the table. So typically, when you're in a non mating disruption environment, one of the easiest ways to monitor if it's available is to put out a pheromone trap. It allows you to attract typically the males, and you can count the numbers, understand the population density and follow the population cycles. When we go into a mating disruption environment, you put out that trap with a pheromone lure in it. And because there's disruption all around, the males no longer able to find that trap to any high degree. So we typically see a very significant amount of what we call trap suppression or inhibition, with traps just with pheromone lures. And we want to see that since it shows us a comfort level of 'Okay, my disruptions are active in the environment, I've got that you know, pheromone cloud going.' So that is a measure that we use. But more and more, we realized that we still want to be able to track flights or population densities, and so we need other tools. And so that's where they've developed other types of attractants to use in the traps that aren't pheromone based. And so there's no confusion about the moth to find them, right? And so some of those, particularly in the Navel Orangeworm system are either the egg traps or the adult female traps that use ground pistachio meal. And that's what she's signaling in on, and more recently, something called phenol proprionate, or PPO attractant that actually attracts both males and females. And that's paired with a pheromone lure. It kind of amps up what we call the PPO attractant. And so those are specifically designed to continue to catch within the mating disruption environment, because they're queuing in on a different type of attractant. What we've seen is some confusion about practitioners and folks putting those traps designed to still catch in mating disruption, putting them in the field, and catching moths and being worried that their disruption isn't working. And so I just caution everyone to make sure you fully understand the type of trap and the type of attractant that you're using within any environment, mating disruption or not, and what that trap data tells you. And if there's any kind of confusion around that, there are experts, I think, you know, within the traps and lures companies, certainly at Suterra. And within the UC and USDA, sort of educational, an extension system that can help people understand all this part of how they're evaluating their disruption, and all of that with these sort of newer monitoring tools. 

Karli Petrovik 32:48 

Okay, great. Well, thank you so much, Emily. That was a very comprehensive view of sprayable and just in general. 

Dr. Emily Symmes 32:56

Thanks, Carly. Take care. 

Karli Petrovik 33:00

Thank you for listening to this episode of the Suterra Trap Talk podcast. Stay tuned for more episodes coming your way soon.