Climate and agriculture: pests, pathogens, and pollinators

[00:00:28]

RICK WEISS: Hello, everyone, and welcome to SciLine’s media briefing on climate change impacts on plant pathogens, pests and pollinators. Definitely one of the more alliterative media briefings we’ve brought to you in the last few years, I will try not to pop my P’s, as we go through these pathogens, pests and pollinators today. I’m SciLine’s director, Rick Weiss. And for those of you who are not familiar with us at SciLine, we are a philanthropically-funded, editorially independent, free service, entirely free service, for reporters and scientists. Our mission is simply to make it as easy as possible for you to include scientist sources and scientific information in your news stories, whether those stories are about a topic in science, or are simply about things going on in your community, whether it’s something like homelessness, downtown development, immigration issues, transportation issues. It turns out that scientists study pretty much anything you can think of. And we can help get you in touch with a scientist source, who can strengthen your story, and tell you what the evidence and the research says, on almost any topic you’re writing about. To do that, you go to sciline.org, click on that blue button that says, “I need an expert”, and we will get working for you to do that outreach and find someone who will help your story. While you’re there, check out the other free services that we can offer you to help your reporting.

Couple of quick logistical details before we get started with today’s briefing. We have three panelists, who are going to speak to you first, for up to about seven minutes each, and then we’ll open it up for Q&A. If you have some questions, either during the presentations, or after they’re done, please go to the bottom of your Zoom screen, and hover over the Q&A icon. And go ahead and let us know your name, your news outlet and your question. And if you’d like that to be directed to anyone in particular, let us know that as well. The video that we will record today, during this briefing, will be posted on our website pretty soon after the briefing is over. And a transcript with timestamps will be added a day or so after that. If you need anything sooner than that, please get in touch through the Q&A box, and we will get you raw video as soon as this briefing ends.

I’m not going to take the time to do full introductions of all three of our guests. Their bios are on the website. But I will just tell you that we will hear first from Dr. Jan Leach, who is an associate dean for research at Colorado State University. And she’s going to cover the pathogens part of our alliterative briefing today. She’s going to talk about how pathogens affect plants, what we know about the impacts of climate change on that relationship, and the potential for all that to affect food security. And second, we’re going to hear from Dr. Hannah Burrack, who is department chair and professor in the department of entomology at Michigan State University. And she’s going to focus on agricultural pests and the impacts of climate change on those pests. And that’ll include some key pest management challenges, and some mitigation strategies. And then third, we’ll hear from Dr. Margarita López-Uribe, an associate professor of entomology at Penn State, who’s going to focus on pollinators, with a particular attention on bees. And with some practical advice, not just for farmers, but for gardeners, too, about how we all can help keep this important pollinator ecosystem healthy. And so with that, I think we should just get started. So I’m going to turn it over to you, Dr. Leach.

[00:04:09]

JAN LEACH: Okay. I will share my screen. And can you tell me if you’re seeing the screen?

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RICK WEISS: Looks good.

[00:04:21]

JAN LEACH: OK. So thank you for this opportunity to present a brief overview of plant pathogens, and how climate change is impacting plant diseases globally. To start off, I’m going to give you a few definitions. So just like humans, plants get sick, too, and they get they get diseases. And we define disease as the abnormal functioning of the plant. Infectious diseases, by plants, are caused by diverse pathogens, which include virus, fungi, bacteria, oomycetes and nematodes. Some of the major plant diseases caused by these pathogens are shown here. One of the most important viral pathogens is the wheat streak virus, which causes wheat streak mosaic disease. This reduces yields in wheat, and in 2017, caused up to about $77 million in wheat crop loss across the Midwest. Bacteria cause a disease called citrus greening, which is a major threat to the citrus industry in Florida. And if you’ve watched orange juice prices over the past few years, or if your gin and tonics are getting more expensive because of the limes, it’s because of this disease. It’s a major problem with over $1 billion per year in losses, and thousands of dollars, or thousands of jobs annually lost.

Another pathogen, that’s a big concern in the U.S., is the wheat blast pathogen. Currently, this pathogen is not found in the U.S., but it is in South America, and it’s moving north, and our wheat producers are hugely concerned about this problem. The next pathogen that I’ll show you is the potato late blight pathogen, which is an oomycete. Now, this is the pathogen that caused the Irish potato famine in the 1840s. And it still remains an important pathogen in the United States in all potato-producing areas. The last I’ll talk about are nematodes, which are the largest of the group. The soybean cyst nematode causes economically important diseases of soybean, and you cannot eradicate the pathogen once it’s in the soil, which is why it is a major concern, our soybean production in the U.S. So to cause a disease, a pathogen requires a susceptible host, and a conducive or a suitable environmental condition. We call this the disease triangle.

Now, environmental changes that are being—that climate change is tormenting us with our things like temperature stresses. So high temperatures are occurring in a lot of locations, or heat stress. Drought or flooding are two types of water stresses that we’re seeing. And nutrient stress is caused by carbon dioxide increases in the environment. Carbon dioxide, we think of as making the plants grow faster and producing more biomass. But the issue is, is that while they’re bigger plants, they’re less nutritious. There’s less protein, and less amino acids that are critical to our diets. So this is a big problem, and can impact not only the health of the plant, but the health of the people that consume the plants. So how does environment impact disease? Well, we’re seeing that under higher temperatures, or changes in the climate, we can see either increased or decreased virulence of different pathogens. This is because the virulence factors produced by the pathogen may either be more efficiently transported from the pathogens, or they may be increased.

Now, virulence factors are the proteins or compounds that allow a pathogen to cause disease or infect a host plant. We’re seeing increased prevalence and dispersal in the range of plant pathogens. And this is either by wind or by movement by humans. And as these pathogens move into new areas, the plants in those areas are naïve. They have never seen these pathogens, and therefore, they may be more susceptible to the diseases. Finally, another issue is that the plant immune system may become compromised. So plants have an immunity system or a disease resistance. It’s different than ours, but it’s very elegant and very functional. And under high temperatures, for example, or drought conditions, we’ve seen that these immune systems are rendered ineffective. Now the part of the—of our problem is that understanding what’s happened to plant diseases, as climate changes, requires a fundamental change in how we approach and study diseases. We typically study things one disease at a time, or one stress at a time, like heat stress, we look for heat tolerance, or disease pathogen attack, we look for disease resistance. But the problem is, is that when these two stresses occur at the same time, we can’t predict the outcome, because we don’t know. We’ve always studied things individually. And oftentimes, the outcome is different. We know already that the outcomes of combined stresses, for example, heat—pathogen attack stresses can vary under heat conditions.

And the sources of resistance to disease, in many cases, are rendered ineffective at high temperatures. Now, it takes us 10 to 20 years to identify a source of resistance, and move it into a new crop species through traditional breeding practices. So that makes this kind of a breakdown very alarming. We have a lot to learn about how plants and pathogens interact, and in these different scenarios with climate change conditions. But we need to think about this as a system, and not just one at a time. So in the last few seconds, I’d like to talk about mitigation strategies as we look to the future. Our mainstay for helping plants thrive under threats of disease, or under conditions of disease, is to improve their genetics through breeding or genome editing the newer approaches. But since we don’t understand much about how the disease and the environmental stresses interact, we don’t have a clear idea of what genes or traits to pursue.

So this is a very intense area of study. Over the past several years, we’ve made great progress in understanding more about how a plant’s microbiome can help a plant adapt to and tolerate stresses, such as climate stresses. And also, how this might help these, the microbiome might help to mitigate diseases. But we don’t know if we have combined stresses of high temperature and disease. Do we—are these—are the microbiomes able to help control the disease? We know that introduction of pathogens into pristine environments, where they’ve not occurred before, can sometimes lead to disasters. Thus, it’s important to always ensure that the plants, or the plant products that we move from country to country, meet phytosanitary require requirements before they cross the borders. Lastly, plant genetic diversity provides an important reservoir of traits that can help crop production systems better adapt to climate change, and reduce the need for external inputs, like pesticides or fertilizers. We need to protect and utilize the sources of diversity in our systems. And lastly, I’d say that I have included a slide at the end with some references that I hope you’ll find useful. And I want to thank you for your time today.

[00:13:12]

RICK WEISS: Thank you, Dr. Leach. Great introduction there, and a lot of interesting concepts. Microbiome, which is so big and human health these days, it’s super interesting to think about how altering the microbial communities around these plants might affect disease. And also the fact that climate change is happening so fast now, that traditional breeding doesn’t have time to keep up with that change. And yet, not everyone’s comfortable with a lot of genetic engineering of food crops. So we’ll see how that plays out as well. OK, let’s move on to our next speaker. And that’s Dr. Hannah Burrack.

[00:13:47]

HANNAH BURRACK: All right. Can you guys see my screen okay?

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RICK WEISS: Yeah.

[00:13:51]

HANNAH BURRACK: Excellent. I’m going to go ahead and get started. So I’m going to be talking about our arthropod pest. So arthropods are insects and their relatives. And first, again, I’m going to orient us to what we’re talking about when we talk about agricultural pest, or what those arthropods pests are. And so we’re talking about, again, insects and their relatives, that cause economic or aesthetic damage to plants in these contexts. And they are highly variable in their life history. So they can have one, a few, or many generations per year. And the impact of a changing climate on those different life histories is going to vary. They might be restricted to one single plant that they eat, or they might eat lots of different things. And we manage those arthropod pests through cultural, so non-chemical tools, biological tools, living organisms that help us control another living organism, or chemical control tools, things like insecticides. So I’ve got a lot of information on this slide. I’m going to bennet [phonetic] for you, but I really would encourage you to ask any questions about specific elements that are here as we enter our Q&A portion. I’ve got seven broad impacts of climate change that we expect to be particularly significant for our insect pests, but I’ve grouped them into three main categories.

The first are those which we anticipate to affect population size and activity time, meaning that we expect to have increasing insect populations, more generations per year, and less of a winter reset that allows us to kind of have a period of inactivity. Then there are impacts that are going to affect pest distribution. So the range of existing pests in a geographic area, and increasing introductions of invasive species, non-native organisms that cause problems in their introduced range. And then finally, our effects that we anticipate having impacts on our management toolbox. So the things that we use to manage insect pests. The tools that we use to model them may not be as effective because of this high variability that we experience in weather and climate. And we anticipate a greater likelihood of resistance to pesticides developing. I’ll talk a little bit more about that as I walk us through a case study.

So I’m going to talk about a particular insect pest that we know a fair amount about, and we’ve done some modeling work to understand what likely impacts of climate change might be. So this is the corn earworm, also known as “Heliocoverpa zea”. That’s the scientific name. I selected this pest, because it is very broad in its host range. It eats more than 100 different plant species. It’s present throughout North America, but it only overwinters in the Southern US, meaning that it recolonizes our Northern States every year after it goes locally extinct in the winter. In the Southern US, it has three to four annual generations. So the places where it lives all the time. It’s also incredibly significant. So when we estimate crop loss from corn earworm in the last year, there were over 76 million bushels of corn lost alone of one of those hundreds plus plant hosts. And then it’s also particularly good at developing resistance to insecticides. So corn earworm by itself has developed resistance to at least 23 active ingredients, and it’s very close relatives developed resistance to more than 120 active ingredients. And so it’s a challenging organism to manage, even under the best times. All right.

So what do we expect to happen for this particular insect? And so here’s just an illustration of some of the key host plants. Across the bottom here, we have tobacco, sorghum, corn, cotton, tomatoes, and industrial hemp over here. And so these are some of the impacted crops, and their susceptible periods shown in the bars next to the icon. And so what we see in our normal kind of status quo, assuming the Southern US here, is that any given crop has been impacted by one, maybe two generations per year. If we shift over two more to three generations per year, from our three to four generations a year, we see that our crops are likely to be impacted by multiple generations. So crops that might be only experience infestation or damage due to one generation, are experiencing two generations or more. And so there’s greater damage potential occurring. And the other thing that is more likely is as we implement our management tools for this pest, there’s a greater likelihood of resistance happening, because we have an additional population that we’re selecting for. And those no longer susceptible individuals, those resistant individuals, can continue to reproduce more frequently in that growing season. Another anticipated impact for this pest is range expansion. And so the purple line here illustrates the current overwintering zone for corn earworm in the United States. Based on soil temperature modeling data looking 50 years out, we anticipate that that insect is going to be able to successfully overwinter where that red line occurs, so places southern—south to have that red line. And so again, much more of the country is likely to be impacted for the entire growing season with this pest, as it’s able to overwinter and successfully live in new environments.

I’m going to pivot a little bit and talk about how we expect climate change to negatively impact our experience with invasive species. There’s a lot of content on this slide. But I just want to break it down for you very simply. When we have the ability to move more items around the world from different places, we tend to get our bugs with them. And so when we can use different shipping lanes, and move goods and supplies in places where we weren’t normally shipping them, and we can ship for longer periods of the year, new things are able to be introduced at a more frequent rate. When they’re introduced into an environment, that is increasingly warmer, and may look more like their native habitat, they’re more likely to survive, establish, develop and cause problems. And once they’re established in an area, they then experience those increases in range expansion, more numbers of annual generations per year, and higher overwintering survival than all of the organisms that are already found they’re experiencing.

So I did also just want to add a little bit about variability. And I really appreciated what Dr. Leach said, which is there’s a lot we don’t know about how insects and their relatives are going to be impacted by climate change. And a lot of this is due to the fact that we’re experiencing not only consistently warming temperatures, but we’re also experiencing periods of increased variability in weather, particularly in local regions. And so things like extreme rain events, or extreme drought conditions, or extreme temperature fluctuation, particularly in the spring and the fall, are going to have really unpredictable effects, depending on the time that they occur, the region that they occur in, and the intensity of those events. And so there’s a lot that we’re still going to have to learn here. And I also want to note that, particularly, due to these highly variable weather conditions on the local scale, we also expect to experience in some things that might be considered beneficial due to a change in climate. So for example, Japanese beetles, who overwinter as pupae and larvae in the soil, are generally less problematic following a drought year, because they experience high mortality when soil conditions are very dry.

Another example is that some of our beneficial insects, that are naturally occurring with some of our invasive species, are now starting to show up sooner than we would have anticipated them to in those introduced ranges. And so the example I’m showing here is our spotted wing drosophila on a raspberry. This is a pest of soft-skin fruit. And it was introduced and detected in the United States in 2008. In 2022, as most—as closely as we can tell, this little parasitoid wasp, leptopilina japonica, which is native to eastern Asia, where this fly calls home, showed up just on its own, and has started attacking and feeding on the flies in their introduced range. And this is sooner than we would have ever expected anything like this to happen. And so there might be some possible effects, that on the short-term, or on the local scale, are positive, as well as the negative and overall concerns that we have.

[00:22:15]

RICK WEISS: That is fascinating. And a great reminder of how quickly things can change when a generation time is short, as it is for so many insects. Things happen fast. And for any of you reporters whose audiences are still having troubles sort of swallowing the concept of evolution. It’s happening right before our eyes right here. So that’s really interesting. Okay. Let’s move on to our third speaker, Dr. Margarita López-Uribe.

[00:22:41]

MARGARITA LÓPEZ-URIBE: OK. So are you guys seeing the right screen? Okay, wonderful. So, well, I am going to talk about pollinators in agriculture. And I would like the audience to kind of like have a shift in their minds, right, like pollinators are things that generally we want as part of agricultural systems. We don’t want to suppress or control. Right? So just kind of like a shift in what we’re going to be talking about. So, well, insects—particularly insects are critical for agricultural systems at a global scale, about 70% of crops worldwide benefit from insect pollination. And this is primarily done by bees and flies. In about 30% of these crops absolutely rely on insects for the reproduction. And let’s keep in mind that these pollinators not are—not only associated with higher yields in these cropping systems, but also things like, for example, quality of fruit, sweetness and shelf life. Right?

So there are a lot of benefits of having pollinators in agricultural systems. This is just a reminder that even though we’re here to talk about pollinators in agriculture, they are also critical to the maintenance of natural ecosystems because the majority of flowering plants need animal pollination to achieve reproduction. But specifically for agricultural systems, what is kind of unique about the way that these pollination systems work is that we have these complementarity, we have this need to have wild pollinators, and we have managed pollinators as well. So the most important common managed pollinator are honey bees, and they are very easy to transport. Right? We can put them in boxes and transport them around for different pollination needs. We also have tens of thousands of individuals in one colony, which is ideal for some of the crops. But they tend to be less effective on a per visit basis. And so this is where the complementary with these wild pollinators becomes really, really critical. So this is important to keep in mind when thinking about stressors, drivers and impacts of climate change, because it is going to be different for managed pollinators and wild pollinators.

So what is the status of these wild pollinators and managed pollinators? I’m going to go over a figure that was published part of a study published in iScience a couple of years ago, where they did—they looked at the patterns of abundance and richness of bees at a global scale. So here in these first figure, we have in the horizontal axis time, so you can see data for the last century. And on the vertical axis, you can see number of records. So the bottom line here is that in the past two decades, we’ve had an increased number of observations of bees, which is likely related to the fact that people are paying more attention to bees, so there are greater efforts to collect them and report them. But when we look at the same time period, and we translate these observations into the number of species that are being detected, we see this very significant decline. So bottom line, what is happening is that we are detecting fewer species of these wild pollinators.

Now, when we look at the statistics for managed pollinators, this is very different. So this is a very similar figure on the x-axis, or horizontal axis, we have time started in 1950, and then we have number of colonies at a global scale. So what we can see is that, overall, at a global scale, we have an increase of honeybee colonies throughout the past century. Right? So honeybees are not really—the number of colonies are not really in decline. When we’re talking about managed pollinators. When we zoom into, like, what is happening in the U.S., here, we have data from the USDA, comparing the average number of colonies for the years 2000 to 2009, to the average number of colonies for the years 2000 to 2020. And so what we can see is that in the US, we have pretty much plateaued into about 2.5 million colonies. These numbers have slightly changed. So for example, here, we have a slight, slight lower number of colonies. This is likely associated with colony collapse disorder, which was something that happened in 2007. But we see pretty stable numbers overall. This does not mean that beekeepers are not having a really difficult time keeping these honey bees alive. Right? So these honey bees are stressed, and still, honeybees, beekeepers are losing about 40% of their colonies every year. Also, keep in mind that 90% of all of these colonies, in the United States, are trucked to California for almond pollination. Right? So basically, we need a lot of these honeybees for crop pollination, and we’re kind of like maxing out the system.

So what is happening with pollinators, and how are they responding to climate change? So this is going, this is going to be alluding to some of the mechanisms that were presented in the two previous talks, right, like these stressors are interacting with each other. And so the responses are really complex. And so we can think about, for example, how decrease in—decreasing nutrition, lower availability of flowers, because there is loss of habitat for bees, in combination with greater exposure to insecticides, due to the proximity to agriculture, can make bees, for example, more susceptible to pathogens and pests, and how all of these interactions can be exacerbated by changing climate. But if we want to zoom into impacts of climate change, and pollinators, I want to, I want you to think about two different kinds of mechanisms, right, so that are, that are direct effects on pollinators on individuals, right? These are generally tolerant to heat, compared to other insects. And so one of the things that is, that is showing, showing up in the literature is that the responses of these bees, for example, increases in temperature are nonlinear. If there is a little bit of an increase in temperature, right, like that may be beneficial for foraging or for reproduction. But then past a certain point, right, is when you start seeing significant declines. And these can be observed in things like foraging and reproduction. But also, there can be indirect effects for pollinators. So for example, there are already observed in mismatches between the phonology of pollinators in the phonology of plants. So when bees are emerging, and when the plants are emerging, particularly for spring, like, early season plants and bees, they seem to be queuing to different environmental conditions. And so the bees tend to, for example, emerge first, and there are no flowers yet. So there is a mismatch, which impacts the reproduction of the pollinator, but also impacts the reproduction of the plant. OK, so I wanted to leave, to leave these—with these slides, about recommendations, and what to do to help bees in the context of all of these different stressors and climate change. A very simple thing, and this is true for homeowners or people in the agricultural sector, is to plant flowers, right, that are two full benefits of this. You can provide food for pollinators, and you can help capture CO2 as well.

There is also a big problem with what I was mentioning before, these were kind of like maxing out our capacity to pollinate crops. We cannot seem to go beyond 2.5 million colonies in the US. And so our capacity to keep pollinating crops is going to be limited at some point. So the reduction of food waste seems to be more important now than ever. We still waste about one third of everything that is produced in the U.S. Goes to landfill. So that’s a second, easy—relatively easy thing to do. And for pollinators is very important to minimize the use of pesticides, right. We need pesticides, to control pests, to control pathogens in agriculture. But if they are needed, if they are in need, they should be used responsibly. And so learning to read labels and not mixing things. For pesticides, not applying more is not necessarily better. So that is kind of a take-home message for this. And I guess with that, I guess, I would let you, Rick, move onto the questions.

[00:31:37]

RICK WEISS: Fantastic. Thank you for that great overview of pollinators. And among many things, a great reminder of the importance of wild pollinators as well. We focus so much time, sometimes, on the hives. I seem to remember a story in The Times about laziness in the animal kingdom many years ago, that made the case that these are not as busy as they’re made out to be. And it’s interesting to hear you say they’re not maybe as efficient pollinators as some of their wild relatives. We won’t get into that today, I think. So let’s get started. And questions, I’ll remind reporters, this is a good time for you to put some of your questions into the Q&A icon at the bottom of your screen there. But while we load those up, I do like to start these briefings with just one question for each of our speakers first. Which is to ask them to talk to you not as just the scientists that they are, but as news consumers that they are, and what they see, and maybe like, or don’t like, so much about what they see in the news about their field of study, that we’ve just been talking about. And whether they have any either kudos or advice to the reporters who are attending today, as you all go forward with your stories. So let’s go around the room first, and just hear what these folks, as news consumers, have to say. And I’ll start with you, Dr. Leach.

[00:32:55]

JAN LEACH: Sure. I would like to suggest that we need help from the press. And we need help to educate the public about how fragile our agricultural system is in the face of climate change, and how we need to prepare for this challenge now. We can’t, we can’t keep putting this off. We need to understand that this is a system. And we need to work with it as a system, which is going to require that we collaborate across the sciences, but also with the public, and with the press to help educate folks on how to move this forward.

[00:33:37]

RICK WEISS: Great. Thank you. And Dr. Burrack?

[00:33:41]

HANNAH BURRACK: Yeah, so I have two things. The first is very simple. One is: not every bug is bad. And so oftentimes, the questions I’ll get from media are around, “How do I get rid of this?” Or even the general public, “How do I kill this,” or, “Is this a problem?” And the vast majority of insects you encounter in your daily life are perfectly happy to go about doing what they’re doing, and let you do what you’re doing. And so then the second one, I would say, is, pest management, in agriculture, is a really complicated principle, and it’s not undertaken lightly when growers are utilizing, say, pesticides. And so the communication around pesticides, particularly when you think about like the dirty dozen list that comes out, and other things that are communicated around conventional versus organic agriculture. In almost all cases, if a farmer is using a pesticide, it is their last option. They’re not—they have already exhausted all of the non-chemical tools that they have at their disposal that work in their operation. They’ve exhausted the biological tools that they have available to them. And it’s because something has broken along the way, that they need to go in and take corrective action. And they’re using the least amount possible, as efficiently as they can, in most cases, because it costs them money. It’s not a free, it’s not a free thing for them to use.

And so I think those—the whole communication around, like, how pesticides are utilized, it doesn’t do anybody any favors. It’s not helpful for consumers to understand how if they’re, if they’re scared of pesticides being used, and it’s not helpful for the practitioners, because then there’s a risk for them in kind of clearly communicating what the constraints on their production practice is, if the perception is going to be, oh, no, there’s more chemicals on there, and that’s bad for me.

[00:35:32]

RICK WEISS: Hmm. Very interesting. Appreciate that. And over to you, Dr. López-Uribe.

[00:35:40]

MARGARITA LÓPEZ-URIBE: Yeah, I think that I really struggle with the—and this is difficult, right? So I—it’s not like I have the solution to the problem that I’m going to bring up. But the science and the outputs of science have, in many cases, context dependency, right. So it depends on kind of, like, what is the best available data. And that is often difficult to convey to the public. Right? It’s not that we have absolute truths that are going to be like that forever. And so sometimes, there is that misconception that if there is a study concluding something, then that is the absolute truth. And we should do something for the rest of our lives. And the reality is that, now, everything is changing around us. Right? And so it is not—the fact that scientists may change recommendations for certain things, over time, doesn’t need the science is bogus or is wrong. Right? And so I think it is, I think it’s an important message that we need to convey as scientists, but also the media needs to kind of like help us translate. So I think that that would be my suggestion.

[00:36:54]

RICK WEISS: Great lesson learned. I think a lot during COVID, as well, that the science is going to change, and it doesn’t mean that scientists didn’t know what they were talking about in the first place. Great. Okay. Well, let’s get into some questions from reporters. And I’ll start with this one from Elizabeth Hilborn, who’s a freelancer, and raises the issue that we know that systemic insecticide use has two effects on crop pests; one, that they’ve been in use long enough that some crop pests have developed resistance, but that also they can kill some beneficial insects like predatory insects on pests that help control crop pests. “Is there evidence that crop pests have significantly increased in cropping systems that do not use systemic insecticides?” In other words, what do we know about the balance here of the value of some of these imperfect pesticides?

[00:37:49]

HANNAH BURRACK: Yeah, so I’ll tackle that one, at least relative to insects. It is a hard question to answer, because I can say definitively, that there have been increases in pest pressure in systems where systemics are not used. And that, largely, has been driven by things like range expansion, introduction of invasive species. So things that are independent of the insecticide use pattern in those crops, but have resulted in greater pests being there. To speak to the systems in which systemics are used, I think you’ve really hit the nail on the head, in that the risk of a systemic insecticide being utilized is more that the resistance to the—the resistance to that pesticide can develop in the target organism. And sometimes, I will say this is not a rule, but sometimes that resistance can develop a little bit faster because that material is present in the plant for a longer duration. And so there’s an exposure to a sublethal concentration, a concentration that’s no longer toxic to the organism at a sooner rate. And so that that can absolutely occur in those systems. I won’t say it’s unique to systemics, though. I think that same pattern occurs with a lot of our topically or our contact materials as well.

[00:39:05]

RICK WEISS: Hmm. Anyone else want to comment on that from the—other than a pest perspective?

[00:39:12]

MARGARITA LÓPEZ-URIBE: Yeah, I guess I’ll—I’ll comment from the pollinator perspective, or like for us, we’re always like trying to be not as pro-pesticide. But, I mean, I think there is very exciting science demonstrating that if you use the right, the right insecticides, and you use them following the label, and only using old-fashion IPM concept, threshold-based recommendations, that benefits—the pollinators benefits the crops, right. So, again, keeping—and going back to the question of the systemics. I think the answer to that is going to be very much crop-dependent. Right? Like, there are some crops where the systemics are being applied at the seed stage, and they kill a very particular crop. The pest study is not very significant, and still, we’re leaving kind of all of these pesticides in the environment. But are they all bad? No. And again, so this is the context dependency that I was trying to convey a minute ago.

[00:40:19]

RICK WEISS: Mm-hmm. Great. OK. So we have a question here that I think will apply for a lot of reporters, who are writing stories in agricultural areas, where their readers include people working in that sector. “As research emerges and evolves in these areas. How can farmers stay up to date on implications for managing their own crops?” I know back in the day, when I was in college, extension services were a big way that universities, maybe land grant universities, in particular, stayed in touch with farmers. I don’t know if that system is still active. I see some nodding heads. So yeah. Why don’t I start with you, Jan? Do you have anything to say about that?

[00:41:04]

JAN LEACH: Sure. And this is one of I think, one of our biggest crises is that we have lost a lot of our extension services across the, across the United States. We used to be the envy of the world for our extension services, because we could take the message of the researcher out to the field, but with funding losses, and also sometimes because industry has stepped in, and they’re—they’re making recommendations about applications of things. But I really feel the loss of having interactions with our extension researchers to carry what results we have out to the fields. And I think this—this is something that our, our agricultural system is really suffering from, is getting the message out, in an accurate and scientific way, to the farmers, getting the application of what we’re finding in science, it’s a big loss to us.

[00:42:12]

RICK WEISS: Hannah, Margarita, do you want to weigh in on how farmers can stay apprised of things?

[00:42:17]

HANNAH BURRACK: I mean, I would just say like extension, the extension system is still probably your best bet to receive that information in an unbiased fashion. And I think what Dr. Leach was really touching on here is while there are lots of different streams of information coming at growers, the real value from our extension systems are that they are science-based; they’re tied into universities, and their bottom line does not depend on the product that you purchase, or the ultimate decision that you make. They just want to give you the right information to make the right choice. And so I also echo the comment that, like, resources to the extension system have dwindled in the last, say, 40 years. And I think continuing that investment, and making sure that we have those boots on the ground personnel throughout our states, who have connections with their local communities, and understand what the driving forces are in those local areas is really important to continuing to have the stream of information delivered efficiently.

[00:43:15]

RICK WEISS: Hmm. Yeah, it sounds a lot like the advice we give to reporters when we train reporters in covering science in the first place. Just because someone has a conflict of interest, as some of these advertisers and producers of pesticides do, it doesn’t mean you can’t trust anything they say. But it is a signal. It’s worth noting and to find independent sources, like some of these university programs, is a great way to go. Here’s a question from Yvette Fernandez from Nevada Public Radio: Are there crops/vegetables that we are losing due to climate change? Anything clearly in decline that you can link to climate change at this point, or is it too complicated to make that causal?

[00:44:01]

HANNAH BURRACK: So I will tell you—I’ll tell you a story. It’s not necessarily that we’re losing an individual crop. But the varieties and cultivars that have been adapted to regional areas are no longer as well adapted for them. So for example, blueberries require chill hours in order to make a fruit. So they have to have a certain time, under a given temperature, in order to grow a berry. And then once they’ve hit those chill hours, it’s go time, so they start blooming. And so if spring happens earlier, or if dormancy breaks earlier, and we still experience these highly variable spring temperatures with periodic freeze/thaws, places like the Upper Midwest here, where it used to be pretty safe to grow blueberries, you didn’t have to do a whole lot of jumping through hurdles to protect them from frost, because once it got warm, it was warm, are now much more like the Southeastern US. Where they break dormancy or Earlier, and then they have an extended period of susceptibility to freeze and frost. And so they require a lot more production, a lot more babying a lot more sleepless nights for people who are trying to protect those plants, so they continue to have fruit on them.

So it’s not that you can’t grow blueberries here, it’s that the varieties, that have historically been adapted to grow here, aren’t quite as happy anymore. And they’re more intense and difficult to manage. So I think that’s more of what’s happening in a lot of systems, is that the things that have been regionally-adapted, are losing their adaptations, and maybe they’re better for somewhere to more northern latitude. And then when you retain some of those crops in an area, the things you have to do are more intense, and require more effort, and require more detail to manage. And so that just adds, yet, another thing to that farmers to-do list, and makes the whole process a lot more challenging.

[00:45:55]

RICK WEISS: Yeah, I could imagine for— a farmer, to have to move to an entirely new crop, because that’s where they live, is not an easy thing either. Go ahead. Sorry, Dr. Leach.

[00:46:03]

JAN LEACH: If I could—sorry, I was—I was going to say that was a great answer. And there may be a positive thing to this. So we have relied hugely on wheat, rice, corn, as crops. And these are important crops. They’re the mainstays of our food sources in our economy. But this may be an opportunity to bring some of the orphan crops, the crops that we’ve kind of ignored, that are highly-nutritious. And they may be able to fill some of these gaps. And so I’ve seen a lot of work, internationally, of people thinking about what kind of crops that could we be growing, like quinoa, or things like that, that are tolerant to the conditions. So it may be an opportunity that we need to think about bringing to the table as well.

[00:46:56]

HANNAH BURRACK: Yeah, and I will just add those are super exciting, and I think that is absolutely an opportunity. I think the other thing to keep in mind is that as we expand into new crops, particularly things like millet, quinoa, the crops that have greater drought tolerance, along with that has to come a marketing and infrastructure pipeline to efficiently utilize those crops. So it’s not, you can’t just tell a farmer, “Hey, I’m going to plant a field of quinoa this year.” You need to have someone who’s going to process it, someone who’s going to purchase it, an end user market, that’s going to utilize it. So that’s the other thing that people have to keep in mind, right, is like people—there are the opportunities for growers to adapt to climate change through new crop production, but that also involves an infrastructure shift to support those crops once they’re in the ground. And so there needs to be a greater investment than just the farmer saying, okay, well, I’m going to grow this drought tolerant plant, and that’ll solve my problems.

[00:47:52]

RICK WEISS: That’s a really—

[00:47:54]

JAN LEACH: Oops, sorry! And understanding the pests and pathogens that are going to come along with those new crops.

[00:48:01]

RICK WEISS: Yeah. Yeah. That’s super complicated. Here’s a question that we’ve got for Dr. López-Uribe: “What’s the current thinking about the cause of colony collapse disorder? As farmers change their practices to adapt to a changing climate, are there things they need to avoid to prevent colony collapse?”

[00:48:24]

MARGARITA LÓPEZ-URIBE: Yeah, well, so colony collapse was kind of a syndrome that was reported back in 2007. So the symptoms that we observed were, basically, beekeepers would go to their bee yards, and all the bees would be gone from the from the hives, right. So no bodies, no nothing, they would just leave. What was the single cause of colony collapse started? I don’t think we were able to nail exactly what was the driver, it is, it was likely the epitome of a lot of different stressors impacting colonies in certain areas. So, it is not something that is commonly reported among beekeepers, especially commercial beekeepers, but still, beekeepers have a really difficult time keeping their colonies alive. And so that was part of this statistic that I shared, between 40 and 50% of the colonies every year die. And I mean, that are—all of the factors are playing a role right, like, we have lots of pests, the bees are having a hard time finding enough food. And there is a lot of exposure to pesticides that poor honeybees that do agricultural pollination contracts, they leave those contracts very weak because of all the exposure to pesticides and fungicides. So I mean, again, what can farmers do? I think that the best is to try to incorporate IPM practices, and minimize a plan to protect pollinators when you’re developing your pesticide application regime for the year. Again, the science says – supports if you’re just applying pesticides on the clock, that is not going to solve the pest problems. It’s going to increase resistance. It’s going to bring secondary pests to your crops. It’s going to kill pollinators. Right? So I think this is a message that we need to continue to convey to growers.

[00:50:35]

RICK WEISS: Hmm. OK. Here’s a question that I can relate to from some of my past: “Are there modern success stories, or recent examples you can share, of crops being developed or modified to be more resistant to pathogens or pests?” I will tell you that back in the 70s, I was on a research project to develop potatoes that were resistant to aphids. And it was a 20-year project because it was just breeding. I know there are much better techniques available today. Not everyone loves them, but they are faster. Are they working? Are there some food crops now that are nicely-resistant to pests or pathogens, thanks to genetic alteration, or editing, or other techniques?

[00:51:26]

JAN LEACH: I can speak to that. There’s an example that has recently been published, and they’re working to get the approvals to release these crops out into the world. So it happens to be a rice disease that’s a major pathogen throughout the world. And using knowledge of how the pathogen causes disease in the plants, they were able to use genome editing, where they changed a few nucleotides. So it’s like if you’re reading a dictionary, and you change how you how you spell one word by two letters. They were able to change this rice—these rice plants to be resistant to multiple strains of this particular pathogen. And this is work that’s been supported by the Bill and Melinda Gates Foundation, and has been published, and they’re working on getting it released. So it hasn’t been put out to the fields to be tested, which is a critical step, obviously. But it has, it is effective.

[00:52:36]

RICK WEISS: Interesting. Are there other examples, anyone wants to highlight?

[00:52:44]

JAN LEACH: Well, of course, there’s the bacillus thuringiensis toxin that it—that we’ve introduced into plants to control, like BT toxin, helps the plants to be resistant to insects that ingest the protein. And it’s completely safe for us. So those are genetically modified plants. But those are genetic, the difference between genetic engineering and genome editing is a little bit different. Those are much, much bigger differences, but still have been used for many, many years.

[00:53:18]

RICK WEISS: Mm-hmm. Yeah. Yeah, I think for reporters, gene editing is—does seem to be the future, or at least just changing with the plants already were endowed with, as opposed to putting something completely foreign. And I’m seeing that we have a follow-up question from Yvette Fernandez at Nevada Public Radio. Can you discuss further, the issue of reducing food waste? How important is this to the overall picture? That was an interesting, I think, unexpected element in there.

[00:53:48]

MARGARITA LÓPEZ-URIBE: Yeah, and maybe this is—I think having discussions in in a class that I’m giving right now about the importance of food waste. And I’m going to—I’m not an expert on that topic, by any means, but there’s extensive literature on the impact of food waste, when we look at systems kind of as an energy flow, like connection of where things are produced and where they end up. And again, it’s a huge proportion of the food that is, that is being produced. So I think that the challenge from the pollination, or pollinator perspective, right, is that, for pollinators, for the optimizing pollination of agricultural systems, we have this need to support wild pollinators. Right? Like, so you need to do conservation, and you need to have agriculture. Right? And you have to integrate those two things to really be able to optimize both functions. And so there is this challenge, this tension between we cannot really cut, like, we cannot cut all the forest. We cannot destroy all the natural habitat, because then we’re not going to have these biodiversity that we need for agriculture. And so this is really, in my head, it really is really challenging this idea that we just need to keep expanding agriculture to feed people in the world, because we really are forgetting a huge portion of the food that is produced and not being utilized. Right? So I think, I think I am trying to come up, and this is totally new for me, too, but I think the framework, the arguments, that we use for why we’re doing the things that we’re doing, need to shift, and incorporate this paradigm that a lot of the food that we’re producing is wasted.

[00:55:38]

RICK WEISS: Yeah, thank you. I think we, at SciLine, have done some work in the wasted food arena, and maybe someone will put something in the chat for reporters who want to follow-up on that topic. I think we have time for just one more question.

And this is an interesting one, a little bit out of the box, but I want to throw it out there from Ana Bueno at KXLN Univision 45 in Houston. This year World Migratory Bird Day Campaign will highlight concerns relating to decreasing populations of insects, and implications for migratory birds. I think as you, Hannah, mentioned, not all bugs are bad, and that’s especially true if you’re a bird when you need them for food. Can people on the team here talk about the effects of pollinator declines, or declines, I think, more generally, of insects, and how this might affect migratory birds. Margarita, do you want to—or okay, Hannah, do you want to start with that?

[00:56:33]

MARGARITA LÓPEZ-URIBE: I don’t know, Hannah. The one thing that I can, that I can say is that there is science supporting that when we look at bird communities, the insect feeders seem to be declining faster than other types of feeding habits in birds. Right? So there seems to be an association between insect decline, and declines in birds. So I guess that’s—

[00:57:00]

HANNAH BURRACK: Yeah, and just to add to that. Like, so global insect decline is a really hot topic among entomologists right now. There’s a group of scientists led by Jessica Ware, who was the past president of the Anthropological Society of America, who had some grant funding, some National—some National Science Foundation grant funding to explore drivers of global insect decline and biodiversity. And so that’s interrelated with all of these other things that we expect. And so it’s not just a negative concern for migratory bird populations. And as Margarita said, there is evidence that suggests that insect-feeding birds are at particular risk. But it’s also a concern for agricultural systems in that that is the reservoir for our beneficial insects, who keep our pest insects in check under normal and ideal conditions. And so when we have declines in biodiversity, we also see an increased risk of pest population explosion, because the beneficial predators and parasites, that normally would be feeding on them, are no longer found in areas. And so—and there’s been a lot of studies of this, particularly in areas—going back to the systemic insecticide question. When you have these multi-level interactions with systemic insecticides, they can decrease predator diversity in some, in some cropping systems, and then result in pest populations emerging or exploding, that weren’t typically going to be a concern.

[00:58:33]

RICK WEISS: That’s really interesting. And again, evidence of the complexity of that ecology here that we are tinkering with, or messing with. So we’re just about at the end of the hour, and I’m going to ask each of you to just give us—give the reporters a nice take home nugget for them—from them from each of you. But before we do that, I want to remind reporters on the call today, that as you do log out—log out at the end of this briefing, you will be asked to fill out a very short four-question survey. I know nobody loves getting surveys after everything we do, but it really does help us design these briefings in a way that can keep you interested, that can keep you—keep us helping you as reporters covering science. So please take the half a minute or so it’ll take to fill out that survey. And do check us out  at sciline.org, and on social media. But let me go quickly around the horn, and just at a half a minute each, if you could each tell us one take-home message that you want reporters to really walk away with here, if there’s one thing you want them to remember, what is that going to be? And Jan Leach, I’ll ask you first.

[00:59:40]

JAN LEACH: Yeah. We need to approach climate and disease, and climate and insect pests interactions as a complex system that includes combinations of stresses. We can’t think about that simplistically anymore. And that’s where we’re headed, and that’s the challenge that we face.

[01:00:01]

RICK WEISS: All right. And Hannah Burrack?

[01:00:06]

HANNAH BURRACK: Yes, I would echo that. The actual outcomes of climate change for insect populations are going to be really variable. And in some ways, they’re going to be really hard for us to predict, because they are interacting with so many different things We can make general predictions about some individual species that we know a fair amount about. But there’s a whole lot of organisms that we don’t know much of anything about. That fly that I showed you, that was introduced from Asia into North America, in 2008, nobody thought it was a pest, until it showed up here. And then it caused upwards of $700 million in crop loss, annually, once it was introduced here. And so little changes in a system can have these cascading consequences. And so just because we can’t tell you exactly what’s going to happen, doesn’t mean there’s going to be—not going to be significant changes, and then we’re going to have to come and unpack them as they evolve.

[01:01:05]

RICK WEISS: Hmm. All right. And Margarita López-Uribe? Oh, sorry, you’re on mute.

[01:01:15]

MARGARITA LÓPEZ-URIBE: Okay, it happened to me. Yes. So following up on Hannah’s comment, I think that climate change is really posing a strong, stronger limitations on our ability to, like, continue to grow exponentially, like food energy, right? Like it is, it is already hard with the number of people that we have on the planet, but I think climate change is making all of these even harder. Right? So I think encouraging people to reduce, and recycle, and have these shifts in mindset, that we cannot continue to just grow, grow, grow, and expect like the systems to continue to feed that that paradigm. I think it’s something that we’re going to have to start adapting to, and understanding.

[01:02:09]

RICK WEISS: That’s a great closing point, and great points from all of you. Thank you three, all three of you, for some really rich presentations in Q&A today. I’ve learned so much, and I know everyone else on the line has as well. Thank you, reporters, for your inclusion of science in your reporting, for your interest in this topic. And I encourage you to, again, check us out at sciline.org. And come to us for help when you need a scientist, or some scientific resources, to strengthen your stories. Thanks, all of you, for attending. And we’ll see you at the next SciLine media briefing. So long!