Ping Yu: Hello everyone, welcome to the Blooms and Beyond podcast, a podcast that uncovers plant history, culture, and management through the lens of science.
Ping Yu: I'm your host, Ping. How's everyone doing today? I'm doing great because I have one of my colleagues here, Dr. Erich Schoeller, today joining me to talk about integrated pest management. Along the way, we are also going to talk about his favorite plant and pest, and of course, some wonderful stories behind the scenes. So I don't want to steal any more thunder from our speaker today. Without further ado, here is my conversation with Dr. Erich Schoeller. I hope you enjoy it.
Ping Yu: Hello, Dr. Erich Schoeller. Welcome to the podcast. So before we get started with all this wonderful stuff that we're going to talk about today, can you tell us a little bit about who you are and what you do?
Erich Schoeller: Sure. Thank you for the invitation. It's great to be here and talk to you today a little bit about IPM.
Erich Schoeller: So my name is Erich Schoeller. I'm an assistant professor at the University of Georgia in the Department of Entomology.
Erich Schoeller: And my responsibilities are controlled environment agriculture, integrated pest management.
Erich Schoeller: And when we say controlled environment agriculture, what we're referring to is crops that are grown under a protected structure, be it high tunnels, greenhouses, or vertical farms.
Ping Yu: So there is a fine line with controlled environment and agriculture.
Ping Yu: We can talk about this a little bit more, but can you tell us, is that something you always wanted to do when you grew up, or is it just something you found through your education or your training or your internships along the way that made you end up in horticulture or in entomology specifically?
Erich Schoeller: I've actually had a pretty meandering career trajectory in my life. When I first entered undergrad, I actually entered pharmacy school because I wanted to be a pharmacist. Quickly learned that I did not like chemistry.
Erich Schoeller: I changed to a biology degree.
Erich Schoeller: For the first couple of years of my undergrad, I was very interested in marine biology.
Erich Schoeller: After I did like a three-week camp in the Bahamas for marine biology, I quickly learned I hated swimming all day.
Erich Schoeller: So I wanted to do something land-based and did more of an ecology-focused undergrad.
Erich Schoeller: After doing my bachelor's degree, I went to Louisiana State University, where I was in the Department of Entomology there.
Erich Schoeller: And for a master's, I worked in forestry, dealing with pests that affect the timber industry, realizing that I did not like it.
Erich Schoeller: Having to cut down trees and work in forests around poisonous snakes and plants.
Erich Schoeller: Horribly high temperatures. I needed something a little more moderate in terms of what I physically was doing. For my PhD, I was at the University of California, Riverside, and there I started doing things that were more similar to what I'm currently doing, which is urban or peri-urban pest management. And there I did biological control of insects that were infesting landscape ornamentals.
Erich Schoeller: And then finally, for my postdoc at University of Florida, that's when I really started doing strictly horticultural production indoors, just what I continue on into my current position.
Ping Yu: Wow, it's amazing to see like...
Ping Yu: from pharmacy to forestry all the way to ornamental, like, your trajectory really kind of gives us a hint of how amazing the path to horticulture can be because I have met so many people throughout the years and people keep telling me how different their backgrounds are, but they all end up in horticulture. So you are definitely just showing us the case, but either from pharmacy, forestry, or ended up in horticulture, all dealing with plants, right?
Ping Yu: So, were you growing up with plants or were you like a little boy loving the little pests while you grew up?
Erich Schoeller: Yeah, so I'm grateful that I had a family that really supported nature and my interest in nature.
Erich Schoeller: From a very young age, I grew up in rural sort of surroundings, always out in the country.
Erich Schoeller: Many acres of land, sometimes forested, sometimes not. But from an early age, I was just outside basically from dawn to dusk and playing in different natural habitats. And I was always just so interested in the insects that were in those habitats. Some of our properties, we had 10, 30, 40 acres, and I would just run through the fields with a sweep net and look and see kind of the things that I was catching in my net as a kid.
Erich Schoeller: And so I made insect collections from a very early age and stopped that for a while.
Erich Schoeller: But, you know, I had always been very interested in insects from as early as I can remember.
Erich Schoeller: And on the plant side, my mom always had beautiful gardens.
Erich Schoeller: She was a stay-at-home mom, so she had a lot of extra time.
Erich Schoeller: And she would spend that time doing gardening and landscaping.
Erich Schoeller: And I would go out there and help her plant.
Erich Schoeller: Various things. So between plants and insects, so that's a marriage of what I currently do.
Ping Yu: That's perfect. Well, I feel like a lot of people, if they grow up with plants or they have early exposure to nature, it can give people the potential passion for plants when they grow up.
Ping Yu: That's how I feel like that.
Ping Yu: So in terms of the plant and pest, can you tell us what's your favorite insect and give us the reason why?
Ping Yu: Like, as I am a plant person, I can give you a list of plants that I love, but not specifically for pests.
Erich Schoeller: Right. So being from Wisconsin, I grew up in an area that was pretty heavy in apple production.
Erich Schoeller: And I remember going in the fall to pick apples.
Erich Schoeller: And one of the things that I would always see is these fruit flies that were on the apples.
Erich Schoeller: And they were always very beautiful with brightly colored wings and interesting patterns.
Erich Schoeller: And today I know that those are tephritid fruit flies.
Erich Schoeller: Every species is bright and colorful and has interesting coloration patterns.
Erich Schoeller: You know, there's some really nasty ones out there like Mediterranean fruit fly, which is always something the USDA is trying to prevent from entering the U.S.
Erich Schoeller: And...
Erich Schoeller: And there's other ones like the olive fruit fly, which is already in the U.S. and devastating the California olive production.
Erich Schoeller: They have really interesting behaviors and they tend to hang around large fruits.
Erich Schoeller: So they're pretty conspicuous.
Erich Schoeller: That's something that stands out to me that I remember very young.
Ping Yu: Okay, so basically you kind of carried your passion for insects from your childhood all the way till now.
Ping Yu: What is your favorite plant?
Erich Schoeller: So that would be lilacs.
Erich Schoeller: And the reason for that is my grandmother had a patio and it was completely surrounded by lilacs.
Erich Schoeller: I can just remember how that smelled in the spring.
Erich Schoeller: It was amazing and that was a very special memory for me.
Ping Yu: So do you know, as a plant person, I'd like to throw out some information about lilac.
Ping Yu: The scientific name of lilac, it's actually named after a Greek nymph, Syringa.
Ping Yu: So basically the story behind lilac or Syringa is because this nymph is trying to escape from the god named Pan, who is pursuing her according to the story, and then to escape from his pursuing, she turned herself into a lilac shrub. And then the god found the shrubs and used its hollow stems to make the first pan pipe, the pan flute.
Ping Yu: Because a lot of times lilac is the first flowering or blooming in the spring, it also represents the arrival of spring and new life and also the first emotion of love.
Ping Yu: Well, at least in Europe and England.
Ping Yu: So I guess this would be some conversation you might want to share with your mom.
Ping Yu: I think she might be interested in romantic or cultural and historical information like this.
Ping Yu: Well, every time we go out and see a plant, you're like, "Oh, it's a yellow plant.
Ping Yu: It's a red color flower and all that." But there's a lot of information and stories.
Ping Yu: Behind the plant itself. So that's one of the things that I want to share with you all today. If you have a favorite plant, Google it or do a little bit more research on that and you'll find a lot more meaning behind the plant itself. And I don't know if anyone out there has read the book, it's called Lilac Girls. And if you haven't, do it because that's one of the remarkable books that I read this year.
Ping Yu: The lilac as a plant is set in the front garden of the house where the Lilac Girls story takes place.
Ping Yu: Of course the book doesn't have to do with the lilac plant itself. It's just something I would recommend you to read.
Ping Yu: Anyhow, back to the point with our main topic today. In agriculture or in academia, there are a lot of abbreviations of certain terms that we normally use, but maybe other people, when they first get introduced to some of those abbreviations we're using...
Ping Yu: They may not know what it is.
Ping Yu: So can you tell us, well, what is IPM?
Ping Yu: And just to give a brief introduction of IPM.
Erich Schoeller: Sure. So IPM stands for Integrated Pest Management.
Erich Schoeller: A lot of times we now use IPPM, which is Integrated Pest and Pathogen Management. But specifically for my career, I focus on pests. So IPM is basically a science-based decision support system, which essentially aims to reduce the use of plant protection products to levels that are economically sustainable and that are safe for the environment and human health. IPM is sort of a group of different tactics that we try to utilize as a whole to create a program, we call that an IPM program, that will ultimately help us achieve that goal of relying less on broad spectrum insecticides, for example.
Ping Yu: And for a lot of people, when we talk about IPM, the P, the pest, people would tend to interpret it as pests.
Ping Yu: It's kind of narrowed down to pests only, but can you give us a definition of the pest?
Ping Yu: What is the pest we're referring to here?
Erich Schoeller: Sure.
Erich Schoeller: So when I typically talk about pests,
Erich Schoeller: I'm referring to arthropod pests, which are both insects and mites, which are arachnids.
Erich Schoeller: Those are what my focus is on, but at the same time, when you're managing pests, you're often also managing diseases because insects vector plant pathogens, and you're trying to kill two birds with one stone in that case to prevent plant diseases, and any sort of damage that's actually due to the insects themselves feeding on those plants.
Erich Schoeller: And simply put, a pest is something that you don't want around that's causing you some sort of economic damage to your crop.
Ping Yu: So under that umbrella, I would say this pest refers to anything that people don't want.
Ping Yu: Does that also include weeds in that regard?
Erich Schoeller: Yes, absolutely.
Erich Schoeller: Weeds are definitely pests.
Erich Schoeller: They're unwanted organisms and their presence can often lead to reduced yields in your crop depending on where they are, particularly in field crops where they're directly in the soil with your crop competing for those resources. But even in a greenhouse...
Erich Schoeller: They can be pests because they can harbor unwanted insects on them that might not be in there if you only have the crop.
Erich Schoeller: And they could also be competing for light in your greenhouse as well.
Ping Yu: Yeah, I think that's one of the things a lot of times people are just like, oh, those are just weeds.
Ping Yu: They're only going to compete for the nutrients and water for the plants.
Ping Yu: But in the meantime, they're also providing the habitats for those pests to get into the greenhouse or get into your crop, right? I know IPM involves a lot of steps. It's not an easy task for people to adapt. Can you tell us a little bit more about why people need to adapt to IPM practices in their production?
Erich Schoeller: Right. So as I mentioned, the ultimate goal is to enhance sustainability and reduce risks from pests.
Erich Schoeller: And you're right, there's a lot of pros and cons associated with IPM.
Erich Schoeller: And I can go through both those pros and cons if you like.
Erich Schoeller: One of the pros of IPM is that we're ultimately trying to use less pesticides, right?
Erich Schoeller: Pesticides have a couple of different categories.
Erich Schoeller: I'll break those down into biorational pesticides,
Erich Schoeller: targeted pesticides, and broad spectrum pesticides.
Erich Schoeller: The ones that we're mostly concerned about are those synthetic broad spectrum insecticides because those really can damage the environment and have much higher risk to human health.
Erich Schoeller: Everything we're doing is ultimately trying to lower that.
Erich Schoeller: And the use of pesticides themselves, they can cause complications.
Erich Schoeller: One of the problems with using pesticides is it damages soil health.
Erich Schoeller: If you go to any grower meetings or speak with growers, one of the really hot topics these days is soil health and beneficial microorganisms.
Erich Schoeller: Often the things that we're either drenching into our pot media or spraying on a plant which leads into the soil is killing those microbes and denying the plant anything that you might benefit from that, right?
Erich Schoeller: So another thing you probably hear about is pesticide resistance. And when we use chemical pesticides over and over again, insects reproduce extremely rapidly.
Erich Schoeller: Often there's hundreds of thousands of individuals that can produce over sometimes 10 to 12 generations a year, depending on how warm the climate is.
Erich Schoeller: That just allows for very rapid evolving of resistance to different active ingredients that are in pesticides.
Erich Schoeller: Over-reliance on those active ingredients can breed resistance, which can eliminate anything that's effective there for controlling pests.
Ping Yu: I'm glad that you mentioned about the development of pest resistance to some of the chemicals that they're spraying for over and over again.
Ping Yu: So basically, if people want to slow down the process of resistance development, what kind of things that you would recommend them doing?
Ping Yu: Right.
Erich Schoeller: Sure. Assuming that we're at the point we actually have to use these chemicals, one of the primary tactics that we utilize to prevent insects developing resistance to these is through rotating products, right?
Erich Schoeller: So there's dozens of different products that are effective against a particular pest, and often these chemical companies are developing these products directly...
Erich Schoeller: In ways that they affect the pests in different ways, like either chemically or interacts with a certain system function.
Erich Schoeller: You know, it can destroy the gut. It can prevent them from feeding. It can be a nerve agent, etc.
Erich Schoeller: So there's a group called the Insecticide Resistance Action Committee, or also known as IRAC.
Erich Schoeller: And they categorize all the different pesticides based on their mode of action and how they're killing that pest or affecting that pest's physiology.
Erich Schoeller: And you can look either on the pesticide label, often it will say what mode of action that pesticide is, or you can go online and see what it is.
Erich Schoeller: And you should always try to use, if you're using multiple products, rotating those products with different modes of action.
Erich Schoeller: And the other thing is always use maximum label rates if possible, because if you use something that's too weak, that allows more of the population to survive.
Erich Schoeller: And when more of that population survives, there's a higher chance that they contain a gene that can develop resistance there.
Ping Yu: Now, the disciplines involved with IPM would be horticulture, entomology, plant pathology, and weed science.
Ping Yu: But what are the specific tactics that are involved in IPM?
Erich Schoeller: Sure. I like to think of IPM as sort of the food pyramid that we all learned.
Erich Schoeller: So looking at the pyramid, at the base of that pyramid...
Erich Schoeller: is prevention tactics.
Erich Schoeller: They often say prevention is the best medicine, right?
Erich Schoeller: It helps you deal with problems before they even arise, which will ultimately save you money, not having to deal with the problems in the first place.
Erich Schoeller: Things like that can involve crop rotation.
Erich Schoeller: In the case of greenhouses, that's planting different things at different times of the year.
Erich Schoeller: You don't always have the same crop in the same greenhouse all the time because a certain crop might be suitable for a particular pest.
Erich Schoeller: And if it's always there, their population can continually build up.
Erich Schoeller: But if you remove that crop and they don't have access to it, then it'll eventually die out and the greenhouse will clean out of that pest.
Erich Schoeller: Using resistant varieties...
Erich Schoeller: So in ornamentals and vegetables, the plant breeders spend a lot of time looking at how certain varieties are susceptible to different pest feeding and whether or not they get less or more damage.
Erich Schoeller: So using varieties that are known to be resistant against something that you have a problem with frequently can save you time.
Erich Schoeller: They either don't get damaged at all or they get damaged less to the point that the damage is below any threshold...
Erich Schoeller: you actually have to treat for.
Erich Schoeller: And then, so that's the base, is prevention.
Erich Schoeller: The next step up from that is detection tactics.
Erich Schoeller: So after we've tried to prevent things, now we need to be monitoring for those problems to make sure that we catch them really early on before they become a problem and we start experiencing crop losses. For insects, that can involve a lot of things, but they generally fall under the same concept, what we call scouting. So we need to be out scouting the crop for issues.
Erich Schoeller: Generally that involves walking through the crop and looking at it pretty thoroughly and then taking notes on the issues we're seeing, where those issues are in the facility, when they typically occur throughout the year.
Erich Schoeller: You can have some sort of level of predictability when problems are going to happen, so you can be extra attentive to that.
Erich Schoeller: And then we can use, so that's kind of active scouting.
Erich Schoeller: We can also use passive scouting methods such as insect sticky traps that we would hang in a greenhouse that are attractive visually to these insects. They're going to fly to this trap, get caught, and we can look at these weekly and see if we're seeing any individuals.
Erich Schoeller: That's sort of a passive method.
Erich Schoeller: So active scouting and passive scouting are key detection methods.
Erich Schoeller: So now let's pretend that our prevention and our detection methods have failed.
Erich Schoeller: We now have pests that we have to deal with.
Erich Schoeller: Now we fall into the control section...
Erich Schoeller: of IPM. And within the control section, that broadly falls into three categories: cultural control and mechanical control, biological control, and then chemical control, right? So cultural and mechanical control is things like sanitation, pruning, just things that humans are involved in that can be active measures of prevention.
Erich Schoeller: So not going into the greenhouse wearing your street clothes, for example, wearing gloves to handle crops and then throwing those gloves out so you're not spreading pests and disease.
Erich Schoeller: So those are some examples of cultural control and mechanical control.
Erich Schoeller: Biological control, which we'll talk about a little bit more in depth, is using living organisms to control pests. And we've already sort of touched on chemical control. And I mentioned broad spectrum insecticides, targeted insecticides, and then sort of biorational insecticides within there.
Erich Schoeller: So that's the category we're ultimately trying not to have to get to.
Ping Yu: Well, thank you for the very thorough description or explanation of the IPM.
Ping Yu: You basically kind of drew the big picture for us of the pyramid, which has three layers, and also kind of gave us an idea of some of the steps that if people want to adapt to IPM practices. First, you need the prevention, which is the first layer.
Ping Yu: You want to start with clean materials and know how to grow good plants in the right place.
Ping Yu: And then from there, we go up to the second layer, which is detection.
Ping Yu: So that's when you have to constantly go look and check your plants just to make sure your plants are doing well.
Ping Yu: If you detect any potential symptoms of an issue, react, take actions early.
Ping Yu: And then the last one would be the control part, the...
Ping Yu: third layer of the pyramid, that's when you have to make a decision to control the pest.
Ping Yu: Along that way, we have three different control methods, including cultural control, biological control, and chemical control. Well, chemical control, we kind of basically already touched on, just using pesticides and insecticides.
Ping Yu: Cultural control is kind of similar to the prevention part where you use tactics to help reduce the spread of the pest or the damage of the pest.
Ping Yu: But do you categorize banker plants and trap plants as cultural control or is it more like biological control?
Ping Yu: And what are banker plants and trap crops and how do they work so that we can kind of draw the line of if this belongs to cultural practice or biological control practice.
Erich Schoeller: Right. So you mentioned banker plants and trap crops.
Erich Schoeller: I should first define what that means for our listeners.
Erich Schoeller: So a banker plant is typically a non-crop plant...
Erich Schoeller: that you're placing either within the crop or adjacent to the crop.
Erich Schoeller: And that banker plant is targeting what we call either natural enemies or biological control agents.
Erich Schoeller: And those are organisms that we're releasing into the crop to help control the pest.
Erich Schoeller: And those sort of fall into a couple broad categories.
Erich Schoeller: Predators, which are, you know, preying on the pest; parasitoids or parasites, which kill the pests by laying their eggs inside them, and then their young eat the inside of the pest.
Erich Schoeller: And then things like entomopathogenic fungi and entomopathogenic nematodes are kind of a mix...
Erich Schoeller: between predator and parasite. So the banker plants are targeting the pests through the natural enemies.
Erich Schoeller: On the other hand, trap crops, so those are a crop or a plant that you're putting into the crop.
Erich Schoeller: It's not the same thing as the crop, but they're typically a plant that is more attractive to the pests than the actual crop is. The theory there is that they're going to prefer being on that plant instead of the crop.
Erich Schoeller: So that is a plant that's interacting with the pest directly.
Erich Schoeller: So you asked me whether or not I thought that was more of a cultural control tactic or a biological control tactic.
Erich Schoeller: I feel it depends on if it's the trap crop or a banker plant.
Erich Schoeller: Trap crop, I feel, is much more of a cultural control tactic.
Erich Schoeller: A banker plant is more of a biological control tactic.
Erich Schoeller: And an example of a trap crop we might use would be sweet alyssum.
Erich Schoeller: An example of a pest that likes thrips. So we have thrips in your impatiens, for example. They're going to want to be in your trap crop more than they are in your impatiens. And once they're in the trap crop, you can either spray that trap crop with insecticides so you're not spraying the crop itself, or you can physically take that trap crop out and destroy it.
Erich Schoeller: Either through burning it or mulching it.
Ping Yu: So if I understand it right, so I'm just giving a real live example of the trap plants.
Ping Yu: Basically, for instance, if you want to protect your other plants from deer in your front yard, and I know there are a lot of deer-loving plants out there, pansy is one of them. So for instance, let's say if you want to protect your eggplant from deer and you plant the outside circle of pansy plants so that the deer will chew on the pansy plants instead of the eggplant, so in that way you kind of protect your eggplant from being eaten by the deer. Am I understanding it right?
Erich Schoeller: That analogy is correct.
Ping Yu: Can you give us a little bit more information on that?
Ping Yu: In ornamentals, we're dealing with thousands of different plants.
Ping Yu: What are the challenges for ornamental crops and for growers to use IPM?
Erich Schoeller: Right. So I guess I'll start out with talking about specific challenges associated with ornamental IPM.
Erich Schoeller: At the same time, you know, I talked about the pros of IPM, but I'll also touch on some of the cons I didn't get to mention.
Erich Schoeller: So ornamental crop production, you can think of that as crops that are either grown in a nursery setting or...
Erich Schoeller: Or those that are grown in a greenhouse. They're mainly grown for aesthetic purposes, right?
Erich Schoeller: We're looking for something attractive for our landscape or our house that is pretty.
Erich Schoeller: So floriculture and nursery products are very susceptible to having their aesthetic value damaged by pests.
Erich Schoeller: So there's a very low tolerance for pests in ornamentals that we might not have such a low tolerance level in another crop.
Erich Schoeller: Where we don't care about how they look, right? So people that are growing ornamentals might have to use much stronger tactics to keep those pest levels down to such low levels that they're not damaging how that plant looks, right?
Erich Schoeller: The other thing is, so imagine you're going to your local nursery, right?
Erich Schoeller: As soon as you walk into the nursery center, you're bombarded with hundreds of different plants.
Erich Schoeller: Unlike field production, which might be a monoculture, meaning that there's just one crop grown over a huge amount of acreage, right?
Erich Schoeller: In ornamental or greenhouse production, you have a ton of different plants grown in a very small space.
Erich Schoeller: And that just creates complexity.
Erich Schoeller: And so you might have to use many different tactics in that very small space.
Erich Schoeller: And it can get complicated very fast.
Erich Schoeller: You can have a lot of different pests in a small area, which requires a lot of different management tactics in a small area.
Erich Schoeller: And finally, this isn't necessarily for nurseries, but for greenhouses. These are semi-closed facilities, right?
Erich Schoeller: They are structures that are more difficult for insects to pass through than they would be in an open environment.
Erich Schoeller: For biological control, we're typically releasing those organisms into the greenhouse, and they're feeding on that pest population.
Erich Schoeller: If it's a good natural enemy, they're going to reduce that pest population to very low levels.
Erich Schoeller: What happens when a predator reduces their prey to low levels?
Erich Schoeller: They typically either have to migrate to find another place that has prey or they're going to starve.
Erich Schoeller: And inside a greenhouse facility, they don't really have the opportunity to go find more food.
Erich Schoeller: So oftentimes the natural enemies we're using in those facilities, their populations collapse, and the growers are going to have to buy those products over and over again every time that they wipe out the pests, which can be a little bit expensive.
Erich Schoeller: So, I mentioned I wanted to also talk about some of the cons of IPM.
Erich Schoeller: Yeah.
Erich Schoeller: So that's one of the things is it can be expensive.
Erich Schoeller: IPM versus chemical control measures.
Erich Schoeller: Some studies have found that it can cost as little as 20% more than traditional pest management.
Erich Schoeller: So, often IPM is more expensive than typical insecticide use.
Erich Schoeller: Yeah.
Erich Schoeller: The IPM pyramid.
Erich Schoeller: Okay.
Erich Schoeller: It is technically complex, right?
Erich Schoeller: And it's difficult to implement.
Erich Schoeller: And a grower is constantly going to have to learn and spend time learning about new methods that might be a better solution...
Erich Schoeller: tactic to use in their IPM program. So it's much more hands-on and involved than just spraying a broad spectrum insecticide. And the other thing we kind of touched on is for an IPM program you have to monitor it much more frequently to make sure it's working than you would have to if you're just spraying pesticides.
Ping Yu: Yeah, I agree with that.
Ping Yu: But one of the things that I want to put out there is, well, you would typically think about, oh, IPM might be a little bit more expensive, but it really depends on the lifespan or the time period that you're evaluating the program.
Ping Yu: So I think it's just a matter of time, especially with the challenges we're facing in terms of pesticide resistance development and then the increasing concern with environmental leaching and pesticide contamination and all that.
Ping Yu: That's another reason why we're trying to, hopefully people are going to adapt to IPM a little bit more.
Ping Yu: Again, you have to kind of do the math and say if you are going to buy a biocontrol agent and use it to manage three different hard-to-control pests for your operation.
Ping Yu: And you kind of have to do the math and say, "Okay, this is how much I put in to buy the biological control agent, and this is how much I can save" from the damage caused by the pest I'm going to control with that. And also do the math with if you're going to just spray the chemical and then just do a comparison, then make the decision of which one you would choose. And oftentimes, people, based on the conversations that I had with a lot of different growers, oftentimes they find the biological control agent will give them better control effects economically in the long run. So back to the biocontrol, I know that you have done a lot of research on biocontrol, especially here at UGA. In your lab, you are primarily working on biocontrol. Can you give us one or two examples of the biocontrol for specific pests that your lab has worked on?
Erich Schoeller: Sure. I'll use two pests as an example, just because they have a variety of different natural enemies available for them. And they're extremely important pests in ornamental production.
Erich Schoeller: The first is the sweet potato whitefly. The scientific name is *Bemisia tabaci*. It's a really devastating pest of both field production and ornamentals.
Erich Schoeller: It's an insect that damages plants by feeding on the sap of the plant.
Erich Schoeller: We have a lot of different options to control that pest with biological control.
Erich Schoeller: So the first things that were really developed for that pest were back in the early 1920s, and that was the parasitoid wasp called *Encarsia formosa*.
Erich Schoeller: Parasitoid wasps essentially function by walking across the leaf.
Erich Schoeller: They encounter the pest, and then they basically sting that pest and lay an egg inside of it, and then their young kills that individual pest as it grows into an adult, and then the adult emerges from the body of that pest when it's time.
Erich Schoeller: There's a variety of different parasitoid wasps that are available.
Erich Schoeller: I mentioned *Encarsia formosa*.
Erich Schoeller: Other ones that are really good are *Eretmocerus* species.
Erich Schoeller: Both of those are commercially available for growers to use.
Erich Schoeller: We typically recommend that they use both *Eretmocerus* and *Encarsia* because whenever whitefly is present in the greenhouse, you typically have a couple different species and those two parasitoids work better on some whiteflies and worse on the others.
Erich Schoeller: So most of the time the commercial suppliers give you a mix of those.
Erich Schoeller: So in addition to parasitoids, we also have predators for those.
Erich Schoeller: And for whiteflies, we have predatory beetles in the family Coccinellidae.
Erich Schoeller: And the beetles that work really well for those are specialists, meaning that they really only feed on whiteflies and not other types of insects.
Erich Schoeller: That particular group of beetles is in the genus *Delphastus*.
Erich Schoeller: And the species that's commercially available for whiteflies is called *Delphastus catalinae*.
Erich Schoeller: Here in the South, we also have native species that work even better that might find their way into your greenhouse if they're around.
Erich Schoeller: And then we also have predatory bugs such as *Orius insidiosus* that will feed on the whiteflies. So parasitoids and predators are the two main groups we have for whiteflies. Now for thrips, a problem globally as well as in the U.S. is western flower thrips, *Frankliniella occidentalis*, and that is a really nasty thrips that devastates ornamentals. For that we have a large variety of natural enemies as well, but those all fall really within the predator category. There's not really parasitoids available for that, but we have, like I mentioned, the predatory bugs. *Orius* work really well on those. Unlike the whiteflies, we also have predatory mites, which are little mites that feed on other insects.
Erich Schoeller: The ones that work really well for that, for example, would be *Amblyseius swirskii*, an example of a species that's commercially available for thrips.
Ping Yu: Okay, thank you for the information just for those two pests.
Ping Yu: So there's one thing that I was thinking maybe some other people are also interested in.
Ping Yu: For chemical applications, a lot of people would go look for broad spectrum chemicals, which means one chemical can be effective to control many different pest issues, right?
Ping Yu: Are there any commercially available biocontrol agents that would be considered broad spectrum, which means one biocontrol agent can help protect or control many different pests in their production?
Erich Schoeller: Not in the sense that they're something that controls everything, but we have options that control a lot.
Erich Schoeller: And I mentioned some of those.
Erich Schoeller: *Swirskii*, for example, is going to feed on a variety of different thrips, a variety of different whiteflies, but it's also going to feed on spider mites, for example, which we didn't touch on.
Erich Schoeller: It's a generalist.
Ping Yu: Only this one?
Ping Yu: So it's different, like the chemical that we're using, where one chemical has...
Ping Yu: Well, I wouldn't say everything, but a big range of different pests, right?
Ping Yu: So basically, in the biocontrol world, we only have one of those that has potential to control various pests?
Erich Schoeller: No, I kind of touched on one I already mentioned.
Erich Schoeller: And another one would be *Orius*, which will feed on a whole bunch of things as well.
Erich Schoeller: But yeah, between the mites and the predatory bugs, those are our most generalist...
Erich Schoeller: natural enemies we have, but those will not really help us with mealybugs, for example. They won't help us with scales. They won't help us with fungus gnats. So there's a bunch of pests still that we have to have other options for that they won't take care of for us. So yeah, there's no magic bullet that deals with every single pest out there.
Ping Yu: Oh, okay.
Ping Yu: So I guess that's another reason why we need IPM, which involves a lot of different tactics to control those pests because only certain pests can be managed by one set of tactics. So as an IPM specialist or entomologist, can you give us some suggestions on how to develop a successful IPM program?
Erich Schoeller: Sure. Before I answer that question, I wanted to touch on the other end of the spectrum, which you asked about generalists. But on the specialist side, we have tons of options there. And often we use specialist biocontrol agents because specialists often are more effective than generalists for trying to control a very specific pest.
Erich Schoeller: So we might not have a natural enemy that controls everything, but we do have natural enemies that control one thing and they do it very well.
Erich Schoeller: I just wanted to say that before we move on.
Erich Schoeller: Now, you asked me about how would I recommend setting up an effective IPM strategy.
Erich Schoeller: Well, the first thing, as I mentioned, you know, one of the difficulties in IPM is it does require knowledge and it does require some technical expertise.
Erich Schoeller: So every grower, in order to really be successful in IPM, needs to take time to educate themselves on what the options are and how they work.
Erich Schoeller: That is really the basic first step is education, right?
Erich Schoeller: If you're educated on what's going on, you'll be successful in your pest management strategies.
Erich Schoeller: So that being said, you should have employees that are also knowledgeable, and they're the ones that are going to be out on the front lines, working in your crop, looking at it all the time.
Erich Schoeller: If they don't know what they're looking for and don't know how to properly document the problems, your whole IPM pyramid is going to basically collapse. You need educated yourself and your skilled workers. So that's your first basic step to being successful in IPM.
Erich Schoeller: Know your production and where the risks are.
Erich Schoeller: So when I say risks, where are the parts of the facility where insects can enter, or where are the crops that are most susceptible to pests located.
Erich Schoeller: If you know where you have the most risks, you should be spending the majority of your time monitoring those areas that are high risk because that's the most efficient use of your time.
Erich Schoeller: Know your risks and know your operation is the second step of being successful.
Erich Schoeller: And the third step is diligence.
Erich Schoeller: Don't just scout once during a crop cycle.
Erich Schoeller: For pests, be out there weekly looking for pests or bi-weekly, whatever you have the labor for. The more detection and prevention that you're doing, the greater the likelihood is that you're going to find something before it becomes a problem. And then finally, yeah, I think the last component to be successful in IPM is patience, right? One of the cons of IPM is it's going to take longer to work typically than chemical pesticides.
Erich Schoeller: And a grower has to be patient enough to let IPM work.
Ping Yu: Yeah, it's not just for the IPM to work, basically for a lot of things in life.
Ping Yu: You kind of have to wait and see if this works, if not, and then make the decision if you're going this route or just change your journey to another different direction.
Ping Yu: What are some of your next steps that you are excited about for IPM in your lab in general, and that can help with our industry, with our growers and in their production.
Erich Schoeller: My lab, we have a big focus on biological control, but that's not all we do.
Erich Schoeller: Part of my program is trying to understand what works and what doesn't work from our standard playbook that we have for pest control from what we've researched on ornamental production.
Erich Schoeller: So I focus a lot on the new technologies that we use in these facilities such as LED lighting, sole-source LED lighting production, nanobubble technology, which is creating higher oxygen level environments for enhanced crop growth. One of the things we didn't talk about much was entomopathogenic nematodes, which we're typically applying through irrigation or drenching our crops.
Erich Schoeller: How do they interact with higher oxygen level environments?
Erich Schoeller: Does that increase their efficacy?
Erich Schoeller: I mentioned lighting.
Erich Schoeller: Very interested in how that interacts with pests since insects' behavior is so driven by different lighting quality, spectrum, intensity.
Erich Schoeller: Et cetera, understanding the barriers to some of the more advanced production, hydroponic...
Erich Schoeller: growing facilities, vertical farm growing facilities.
Erich Schoeller: How does that impact the movement of insects and ultimately how we manage them in those really complex growing situations?
Erich Schoeller: Yeah.
Ping Yu: Yeah. So with that in mind, if people want to look for more of what you do and some of your work, where do you recommend they go to look for?
Erich Schoeller: Sure. So I'm on LinkedIn. You can find me, Erich Schoeller. I also have a website, which is schoellerlab.caes.uga.edu.
Erich Schoeller: Where I post what I'm doing and I've got my contact information on there as well.
Erich Schoeller: You can go to the Department of Entomology and see my faculty profile.
Erich Schoeller: My email is available there as well.
Ping Yu: All right. Thank you so much for sharing your experience and stories with us today.
Ping Yu: And again, you're always welcome back to talk more about your research.
Ping Yu: Thank you again for this wonderful episode on IPM.
Ping Yu: Thank you.
Erich Schoeller: Thanks for having me.
Ping Yu: If you're looking for more information on IPM, AFE provides additional resources.
Ping Yu: First, go to sustainablebloom.org/industryguide/ipm.
Ping Yu: Second, you can go to endowment.org/ipm.
Ping Yu: This website also provides you guidance on building an IPM program, as well as resources for SREPs and biorationals.
Ping Yu: To save you time, I will place all those links in the show notes.
Ping Yu: This episode in our first season is made possible through an educational grant from the American Floral Endowment, whose research priorities helped shape the topics that are featured.
Ping Yu: To learn more about AFE and access their research and educational resources, visit their website at endowment.org.
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Ping Yu: Thank you for listening. Till the next time, stay healthy and go plants!
Ping Yu: [music]